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  • Building The Right SharePoint Team For Your Organization

    - by Mark Rackley
    I see the question posted fairly often asking what kind SharePoint team an organization should have. How many people do I need? What roles do I need to fill? What is best for my organization? Well, just like every other answer in SharePoint, the correct answer is “it depends”. Do you ever get sick of hearing that??? I know I do… So, let me give you my thoughts and opinions based upon my experience and what I’ve seen and let you come to your own conclusions. What are the possible SharePoint roles? I guess the first thing you need to understand are the different roles that exist in SharePoint (and their are LOTS). Remember, SharePoint is a massive beast and you will NOT find one person who can do it all. If you are hoping to find that person you will be sorely disappointed. For the most part this is true in SharePoint 2007 and 2010. However, generally things are improved in 2010 and easier for junior individuals to grasp. SharePoint Administrator The absolutely positively only role that you should not be without no matter the size of your organization or SharePoint deployment is a SharePoint administrator. These guys are essential to keeping things running and figuring out what’s wrong when things aren’t running well. These unsung heroes do more before 10 am than I do all day. The bad thing is, when these guys are awesome, you don’t even know they exist because everything is running so smoothly. You should definitely invest some time and money here to make sure you have some competent if not rockstar help. You need an admin who truly loves SharePoint and will go that extra mile when necessary. Let me give you a real world example of what I’m talking about: We have a rockstar admin… and I’m sure she’s sick of my throwing her name around so she’ll just have to live with remaining anonymous in this post… sorry Lori… Anyway! A couple of weeks ago our Server teams came to us and said Hi Lori, I’m finalizing the MOSS servers and doing updates that require a restart; can I restart them? Seems like a harmless request from your server team does it not? Sure, go ahead and apply the patches and reboot during our scheduled maintenance window. No problem? right? Sounded fair to me… but no…. not to our fearless SharePoint admin… I need a complete list of patches that will be applied. There is an update that is out there that will break SharePoint… KB973917 is the patch that has been shown to cause issues. What? You mean Microsoft released a patch that would actually adversely affect SharePoint? If we did NOT have a rockstar admin, our server team would have applied these patches and then when some problem occurred in SharePoint we’d have to go through the fun task of tracking down exactly what caused the issue and resolve it. How much time would that have taken? If you have a junior SharePoint admin or an admin who’s not out there staying on top of what’s going on you could have spent days tracking down something so simple as applying a patch you should not have applied. I will even go as far to say the only SharePoint rockstar you NEED in your organization is a SharePoint admin. You can always outsource really complicated development projects or bring in a rockstar contractor every now and then to make sure you aren’t way off track in other areas. For your day-to-day sanity and to keep SharePoint running smoothly, you need an awesome Admin. Some rockstars in this category are: Ben Curry, Mike Watson, Joel Oleson, Todd Klindt, Shane Young, John Ferringer, Sean McDonough, and of course Lori Gowin. SharePoint Developer Another essential role for your SharePoint deployment is a SharePoint developer. Things do start to get a little hazy here and there are many flavors of “developers”. Are you writing custom code? using SharePoint Designer? What about SharePoint Branding?  Are all of these considered developers? I would say yes. Are they interchangeable? I’d say no. Development in SharePoint is such a large beast in itself. I would say that it’s not so large that you can’t know it all well, but it is so large that there are many people who specialize in one particular category. If you are lucky enough to have someone on staff who knows it all well, you better make sure they are well taken care of because those guys are ready-made to move over to a consulting role and charge you 3 times what you are probably paying them. :) Some of the all-around rockstars are Eric Shupps, Andrew Connell (go Razorbacks), Rob Foster, Paul Schaeflein, and Todd Bleeker SharePoint Power User/No-Code Solutions Developer These SharePoint Swiss Army Knives are essential for quick wins in your organization. These people can twist the out-of-the-box functionality to make it do things you would not even imagine. Give these guys SharePoint Designer, jQuery, InfoPath, and a little time and they will create views, dashboards, and KPI’s that will blow your mind away and give your execs the “wow” they are looking for. Not only can they deliver that wow factor, but they can mashup, merge, and really help make your SharePoint application usable and deliver an overall better user experience. Before you hand off a project to your SharePoint Custom Code developer, let one of these rockstars look at it and show you what they can do (in probably less time). I would say the second most important role you can fill in your organization is one of these guys. Rockstars in this category are Christina Wheeler, Laura Rogers, Jennifer Mason, and Mark Miller SharePoint Developer – Custom Code If you want to really integrate SharePoint into your legacy systems, or really twist it and make it bend to your will, you are going to have to open up Visual Studio and write some custom code.  Remember, SharePoint is essentially just a big, huge, ginormous .NET application, so you CAN write code to make it do ANYTHING, but do you really want to spend the time and effort to do so? At some point with every other form of SharePoint development you are going to run into SOME limitation (SPD Workflows is the big one that comes to mind). If you truly want to knock down all the walls then custom development is the way to go. PLEASE keep in mind when you are looking for a custom code developer that a .NET developer does NOT equal a SharePoint developer. Just SOME of the things these guys write are: Custom Workflows Custom Web Parts Web Service functionality Import data from legacy systems Export data to legacy systems Custom Actions Event Receivers Service Applications (2010) These guys are also the ones generally responsible for packaging everything up into solution packages (you are doing that, right?). Rockstars in this category are Phil Wicklund, Christina Wheeler, Geoff Varosky, and Brian Jackett. SharePoint Branding “But it LOOKS like SharePoint!” Somebody call the WAAAAAAAAAAAAHMbulance…   Themes, Master Pages, Page Layouts, Zones, and over 2000 styles in CSS.. these guys not only have to be comfortable with all of SharePoint’s quirks and pain points when branding, but they have to know it TWICE for publishing and non-publishing sites.  Not only that, but these guys really need to have an eye for graphic design and be able to translate the ramblings of business into something visually stunning. They also have to be comfortable with XSLT, XML, and be able to hand off what they do to your custom developers for them to package as solutions (which you are doing, right?). These rockstars include Heater Waterman, Cathy Dew, and Marcy Kellar SharePoint Architect SharePoint Architects are generally SharePoint Admins or Developers who have moved into more of a BA role? Is that fair to say? These guys really have a grasp and understanding for what SharePoint IS and what it can do. These guys help you structure your farms to meet your needs and help you design your applications the correct way. It’s always a good idea to bring in a rockstar SharePoint Architect to do a sanity check and make sure you aren’t doing anything stupid.  Most organizations probably do not have a rockstar architect on staff. These guys are generally brought in at the deployment of a farm, upgrade of a farm, or for large development projects. I personally also find architects very useful for sitting down with the business to translate their needs into what SharePoint can do. A good architect will be able to pick out what can be done out-of-the-box and what has to be custom built and hand those requirements to the development Staff. Architects can generally fill in as an admin or a developer when needed. Some rockstar architects are Rick Taylor, Dan Usher, Bill English, Spence Harbar, Neil Hodgkins, Eric Harlan, and Bjørn Furuknap. Other Roles / Specialties On top of all these other roles you also get these people who specialize in things like Reporting, BDC (BCS in 2010), Search, Performance, Security, Project Management, etc... etc... etc... Again, most organizations will not have one of these gurus on staff, they’ll just pay out the nose for them when they need them. :) SharePoint End User Everyone else in your organization that touches SharePoint falls into this category. What they actually DO in SharePoint is determined by your governance and what permissions you give these guys. Hopefully you have these guys on a fairly short leash and are NOT giving them access to tools like SharePoint Designer. Sadly end users are the ones who truly make your deployment a success by using it, but are also your biggest enemy in breaking it.  :)  We love you guys… really!!! Okay, all that’s fine and dandy, but what should MY SharePoint team look like? It depends! Okay… Are you just doing out of the box team sites with no custom development? Then you are probably fine with a great Admin team and a great No-Code Solution Development team. How many people do you need? Depends on how busy you can keep them. Sorry, can’t answer the question about numbers without knowing your specific needs. I can just tell you who you MIGHT need and what they will do for you. I’ll leave you with what my ideal SharePoint Team would look like for a particular scenario: Farm / Organization Structure Dev, QA, and 2 Production Farms. 5000 – 10000 Users Custom Development and Integration with legacy systems Team Sites, My Sites, Intranet, Document libraries and overall company collaboration Team Rockstar SharePoint Administrator 2-3 junior SharePoint Administrators SharePoint Architect / Lead Developer 2 Power User / No-Code Solution Developers 2-3 Custom Code developers Branding expert With a team of that size and skill set, they should be able to keep a substantial SharePoint deployment running smoothly and meet your business needs. This does NOT mean that you would not need to bring in contract help from time to time when you need an uber specialist in one area. Also, this team assumes there will be ongoing development for the life of your SharePoint farm. If you are just going to be doing sporadic custom development, it might make sense to partner with an awesome firm that specializes in that sort of work (I can give you the name of a couple if you are interested).  Again though, the size of your team depends on the number of requests you are receiving and how much active deployment you are doing. So, don’t bring in a team that looks like this and then yell at me because they are sitting around with nothing to do or are so overwhelmed that nothing is getting done. I do URGE you to take the proper time to asses your needs and determine what team is BEST for your organization. Also, PLEASE PLEASE PLEASE do not skimp on the talent. When it comes to SharePoint you really do get what you pay for when it comes to employees, contractors, and software.  SharePoint can become absolutely critical to your business and because you skimped on hiring a developer he created a web part that brings down the farm because he doesn’t know what he’s doing, or you hire an admin who thinks it’s fine to stick everything in the same Content Database and then can’t figure out why people are complaining. SharePoint can be an enormous blessing to an organization or it’s biggest curse. Spend the time and money to do it right, or be prepared to spending even more time and money later to fix it.

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  • Beware Sneaky Reads with Unique Indexes

    - by Paul White NZ
    A few days ago, Sandra Mueller (twitter | blog) asked a question using twitter’s #sqlhelp hash tag: “Might SQL Server retrieve (out-of-row) LOB data from a table, even if the column isn’t referenced in the query?” Leaving aside trivial cases (like selecting a computed column that does reference the LOB data), one might be tempted to say that no, SQL Server does not read data you haven’t asked for.  In general, that’s quite correct; however there are cases where SQL Server might sneakily retrieve a LOB column… Example Table Here’s a T-SQL script to create that table and populate it with 1,000 rows: CREATE TABLE dbo.LOBtest ( pk INTEGER IDENTITY NOT NULL, some_value INTEGER NULL, lob_data VARCHAR(MAX) NULL, another_column CHAR(5) NULL, CONSTRAINT [PK dbo.LOBtest pk] PRIMARY KEY CLUSTERED (pk ASC) ); GO DECLARE @Data VARCHAR(MAX); SET @Data = REPLICATE(CONVERT(VARCHAR(MAX), 'x'), 65540);   WITH Numbers (n) AS ( SELECT ROW_NUMBER() OVER (ORDER BY (SELECT 0)) FROM master.sys.columns C1, master.sys.columns C2 ) INSERT LOBtest WITH (TABLOCKX) ( some_value, lob_data ) SELECT TOP (1000) N.n, @Data FROM Numbers N WHERE N.n <= 1000; Test 1: A Simple Update Let’s run a query to subtract one from every value in the some_value column: UPDATE dbo.LOBtest WITH (TABLOCKX) SET some_value = some_value - 1; As you might expect, modifying this integer column in 1,000 rows doesn’t take very long, or use many resources.  The STATITICS IO and TIME output shows a total of 9 logical reads, and 25ms elapsed time.  The query plan is also very simple: Looking at the Clustered Index Scan, we can see that SQL Server only retrieves the pk and some_value columns during the scan: The pk column is needed by the Clustered Index Update operator to uniquely identify the row that is being changed.  The some_value column is used by the Compute Scalar to calculate the new value.  (In case you are wondering what the Top operator is for, it is used to enforce SET ROWCOUNT). Test 2: Simple Update with an Index Now let’s create a nonclustered index keyed on the some_value column, with lob_data as an included column: CREATE NONCLUSTERED INDEX [IX dbo.LOBtest some_value (lob_data)] ON dbo.LOBtest (some_value) INCLUDE ( lob_data ) WITH ( FILLFACTOR = 100, MAXDOP = 1, SORT_IN_TEMPDB = ON ); This is not a useful index for our simple update query; imagine that someone else created it for a different purpose.  Let’s run our update query again: UPDATE dbo.LOBtest WITH (TABLOCKX) SET some_value = some_value - 1; We find that it now requires 4,014 logical reads and the elapsed query time has increased to around 100ms.  The extra logical reads (4 per row) are an expected consequence of maintaining the nonclustered index. The query plan is very similar to before (click to enlarge): The Clustered Index Update operator picks up the extra work of maintaining the nonclustered index. The new Compute Scalar operators detect whether the value in the some_value column has actually been changed by the update.  SQL Server may be able to skip maintaining the nonclustered index if the value hasn’t changed (see my previous post on non-updating updates for details).  Our simple query does change the value of some_data in every row, so this optimization doesn’t add any value in this specific case. The output list of columns from the Clustered Index Scan hasn’t changed from the one shown previously: SQL Server still just reads the pk and some_data columns.  Cool. Overall then, adding the nonclustered index hasn’t had any startling effects, and the LOB column data still isn’t being read from the table.  Let’s see what happens if we make the nonclustered index unique. Test 3: Simple Update with a Unique Index Here’s the script to create a new unique index, and drop the old one: CREATE UNIQUE NONCLUSTERED INDEX [UQ dbo.LOBtest some_value (lob_data)] ON dbo.LOBtest (some_value) INCLUDE ( lob_data ) WITH ( FILLFACTOR = 100, MAXDOP = 1, SORT_IN_TEMPDB = ON ); GO DROP INDEX [IX dbo.LOBtest some_value (lob_data)] ON dbo.LOBtest; Remember that SQL Server only enforces uniqueness on index keys (the some_data column).  The lob_data column is simply stored at the leaf-level of the non-clustered index.  With that in mind, we might expect this change to make very little difference.  Let’s see: UPDATE dbo.LOBtest WITH (TABLOCKX) SET some_value = some_value - 1; Whoa!  Now look at the elapsed time and logical reads: Scan count 1, logical reads 2016, physical reads 0, read-ahead reads 0, lob logical reads 36015, lob physical reads 0, lob read-ahead reads 15992.   CPU time = 172 ms, elapsed time = 16172 ms. Even with all the data and index pages in memory, the query took over 16 seconds to update just 1,000 rows, performing over 52,000 LOB logical reads (nearly 16,000 of those using read-ahead). Why on earth is SQL Server reading LOB data in a query that only updates a single integer column? The Query Plan The query plan for test 3 looks a bit more complex than before: In fact, the bottom level is exactly the same as we saw with the non-unique index.  The top level has heaps of new stuff though, which I’ll come to in a moment. You might be expecting to find that the Clustered Index Scan is now reading the lob_data column (for some reason).  After all, we need to explain where all the LOB logical reads are coming from.  Sadly, when we look at the properties of the Clustered Index Scan, we see exactly the same as before: SQL Server is still only reading the pk and some_value columns – so what’s doing the LOB reads? Updates that Sneakily Read Data We have to go as far as the Clustered Index Update operator before we see LOB data in the output list: [Expr1020] is a bit flag added by an earlier Compute Scalar.  It is set true if the some_value column has not been changed (part of the non-updating updates optimization I mentioned earlier). The Clustered Index Update operator adds two new columns: the lob_data column, and some_value_OLD.  The some_value_OLD column, as the name suggests, is the pre-update value of the some_value column.  At this point, the clustered index has already been updated with the new value, but we haven’t touched the nonclustered index yet. An interesting observation here is that the Clustered Index Update operator can read a column into the data flow as part of its update operation.  SQL Server could have read the LOB data as part of the initial Clustered Index Scan, but that would mean carrying the data through all the operations that occur prior to the Clustered Index Update.  The server knows it will have to go back to the clustered index row to update it, so it delays reading the LOB data until then.  Sneaky! Why the LOB Data Is Needed This is all very interesting (I hope), but why is SQL Server reading the LOB data?  For that matter, why does it need to pass the pre-update value of the some_value column out of the Clustered Index Update? The answer relates to the top row of the query plan for test 3.  I’ll reproduce it here for convenience: Notice that this is a wide (per-index) update plan.  SQL Server used a narrow (per-row) update plan in test 2, where the Clustered Index Update took care of maintaining the nonclustered index too.  I’ll talk more about this difference shortly. The Split/Sort/Collapse combination is an optimization, which aims to make per-index update plans more efficient.  It does this by breaking each update into a delete/insert pair, reordering the operations, removing any redundant operations, and finally applying the net effect of all the changes to the nonclustered index. Imagine we had a unique index which currently holds three rows with the values 1, 2, and 3.  If we run a query that adds 1 to each row value, we would end up with values 2, 3, and 4.  The net effect of all the changes is the same as if we simply deleted the value 1, and added a new value 4. By applying net changes, SQL Server can also avoid false unique-key violations.  If we tried to immediately update the value 1 to a 2, it would conflict with the existing value 2 (which would soon be updated to 3 of course) and the query would fail.  You might argue that SQL Server could avoid the uniqueness violation by starting with the highest value (3) and working down.  That’s fine, but it’s not possible to generalize this logic to work with every possible update query. SQL Server has to use a wide update plan if it sees any risk of false uniqueness violations.  It’s worth noting that the logic SQL Server uses to detect whether these violations are possible has definite limits.  As a result, you will often receive a wide update plan, even when you can see that no violations are possible. Another benefit of this optimization is that it includes a sort on the index key as part of its work.  Processing the index changes in index key order promotes sequential I/O against the nonclustered index. A side-effect of all this is that the net changes might include one or more inserts.  In order to insert a new row in the index, SQL Server obviously needs all the columns – the key column and the included LOB column.  This is the reason SQL Server reads the LOB data as part of the Clustered Index Update. In addition, the some_value_OLD column is required by the Split operator (it turns updates into delete/insert pairs).  In order to generate the correct index key delete operation, it needs the old key value. The irony is that in this case the Split/Sort/Collapse optimization is anything but.  Reading all that LOB data is extremely expensive, so it is sad that the current version of SQL Server has no way to avoid it. Finally, for completeness, I should mention that the Filter operator is there to filter out the non-updating updates. Beating the Set-Based Update with a Cursor One situation where SQL Server can see that false unique-key violations aren’t possible is where it can guarantee that only one row is being updated.  Armed with this knowledge, we can write a cursor (or the WHILE-loop equivalent) that updates one row at a time, and so avoids reading the LOB data: SET NOCOUNT ON; SET STATISTICS XML, IO, TIME OFF;   DECLARE @PK INTEGER, @StartTime DATETIME; SET @StartTime = GETUTCDATE();   DECLARE curUpdate CURSOR LOCAL FORWARD_ONLY KEYSET SCROLL_LOCKS FOR SELECT L.pk FROM LOBtest L ORDER BY L.pk ASC;   OPEN curUpdate;   WHILE (1 = 1) BEGIN FETCH NEXT FROM curUpdate INTO @PK;   IF @@FETCH_STATUS = -1 BREAK; IF @@FETCH_STATUS = -2 CONTINUE;   UPDATE dbo.LOBtest SET some_value = some_value - 1 WHERE CURRENT OF curUpdate; END;   CLOSE curUpdate; DEALLOCATE curUpdate;   SELECT DATEDIFF(MILLISECOND, @StartTime, GETUTCDATE()); That completes the update in 1280 milliseconds (remember test 3 took over 16 seconds!) I used the WHERE CURRENT OF syntax there and a KEYSET cursor, just for the fun of it.  One could just as well use a WHERE clause that specified the primary key value instead. Clustered Indexes A clustered index is the ultimate index with included columns: all non-key columns are included columns in a clustered index.  Let’s re-create the test table and data with an updatable primary key, and without any non-clustered indexes: IF OBJECT_ID(N'dbo.LOBtest', N'U') IS NOT NULL DROP TABLE dbo.LOBtest; GO CREATE TABLE dbo.LOBtest ( pk INTEGER NOT NULL, some_value INTEGER NULL, lob_data VARCHAR(MAX) NULL, another_column CHAR(5) NULL, CONSTRAINT [PK dbo.LOBtest pk] PRIMARY KEY CLUSTERED (pk ASC) ); GO DECLARE @Data VARCHAR(MAX); SET @Data = REPLICATE(CONVERT(VARCHAR(MAX), 'x'), 65540);   WITH Numbers (n) AS ( SELECT ROW_NUMBER() OVER (ORDER BY (SELECT 0)) FROM master.sys.columns C1, master.sys.columns C2 ) INSERT LOBtest WITH (TABLOCKX) ( pk, some_value, lob_data ) SELECT TOP (1000) N.n, N.n, @Data FROM Numbers N WHERE N.n <= 1000; Now here’s a query to modify the cluster keys: UPDATE dbo.LOBtest SET pk = pk + 1; The query plan is: As you can see, the Split/Sort/Collapse optimization is present, and we also gain an Eager Table Spool, for Halloween protection.  In addition, SQL Server now has no choice but to read the LOB data in the Clustered Index Scan: The performance is not great, as you might expect (even though there is no non-clustered index to maintain): Table 'LOBtest'. Scan count 1, logical reads 2011, physical reads 0, read-ahead reads 0, lob logical reads 36015, lob physical reads 0, lob read-ahead reads 15992.   Table 'Worktable'. Scan count 1, logical reads 2040, physical reads 0, read-ahead reads 0, lob logical reads 34000, lob physical reads 0, lob read-ahead reads 8000.   SQL Server Execution Times: CPU time = 483 ms, elapsed time = 17884 ms. Notice how the LOB data is read twice: once from the Clustered Index Scan, and again from the work table in tempdb used by the Eager Spool. If you try the same test with a non-unique clustered index (rather than a primary key), you’ll get a much more efficient plan that just passes the cluster key (including uniqueifier) around (no LOB data or other non-key columns): A unique non-clustered index (on a heap) works well too: Both those queries complete in a few tens of milliseconds, with no LOB reads, and just a few thousand logical reads.  (In fact the heap is rather more efficient). There are lots more fun combinations to try that I don’t have space for here. Final Thoughts The behaviour shown in this post is not limited to LOB data by any means.  If the conditions are met, any unique index that has included columns can produce similar behaviour – something to bear in mind when adding large INCLUDE columns to achieve covering queries, perhaps. Paul White Email: [email protected] Twitter: @PaulWhiteNZ

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  • guvcview recording video and audio out of synchronisation in Ubuntu 10.10

    - by SIJAR
    I finally got Guvcview, a great software for Logitech webcam and it does all the stuff that one wants out of it. But I'm not satisfy with the video recording, video and audio out of synchronisation also video seems to be in slow motion. Please help so that I can tweak in and get a good video recording with the webcam. Below is the log of Guvcview ------------------------------------------------------------------------------- guvcview 1.4.1 video_device: /dev/video0 vid_sleep: 0 cap_meth: 1 resolution: 640 x 480 windowsize: 1024 x 715 vert pane: 578 spin behavior: 0 mode: mjpg fps: 1/25 Display Fps: 0 bpp: 0 hwaccel: 1 avi_format: 4 sound: 1 sound Device: 4 sound samp rate: 0 sound Channels: 0 Sound delay: 0 nanosec Sound Format: 85 Pan Step: 2 degrees Tilt Step: 2 degrees Video Filter Flags: 0 image inc: 0 profile(default):/home/sijar/default.gpfl starting portaudio... bt_audio_service_open: connect() failed: Connection refused (111) bt_audio_service_open: connect() failed: Connection refused (111) bt_audio_service_open: connect() failed: Connection refused (111) bt_audio_service_open: connect() failed: Connection refused (111) Cannot connect to server socket err = No such file or directory Cannot connect to server socket jack server is not running or cannot be started language catalog= dir:/usr/share/locale type:UTF-8 lang:en_US.utf8 cat:guvcview.mo mjpg: setting format to 1196444237 capture method = 1 video device: /dev/video0 libv4lconvert: warning more framesizes then I can handle! libv4lconvert: warning more framesizes then I can handle! /dev/video0 - device 1 libv4lconvert: warning more framesizes then I can handle! libv4lconvert: warning more framesizes then I can handle! Init. UVC Camera (046d:0825) (location: usb-0000:00:1d.7-5) { pixelformat = 'YUYV', description = 'YUV 4:2:2 (YUYV)' } { discrete: width = 640, height = 480 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 160, height = 120 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 176, height = 144 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 320, height = 176 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 320, height = 240 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 352, height = 288 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 432, height = 240 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 544, height = 288 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 640, height = 360 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, ... repeats a couple of times ... vid:046d pid:0825 driver:uvcvideo Adding control for Pan (relative) UVCIOC_CTRL_ADD - Error: Operation not permitted checking format: 1196444237 VIDIOC_G_COMP:: Invalid argument compression control not supported fps is set to 1/25 drawing controls control[0]: 0x980900 Brightness, 0:255:1, default 128 control[0]: 0x980901 Contrast, 0:255:1, default 32 control[0]: 0x980902 Saturation, 0:255:1, default 32 control[0]: 0x98090c White Balance Temperature, Auto, 0:1:1, default 1 control[0]: 0x980913 Gain, 0:255:1, default 0 control[0]: 0x980918 Power Line Frequency, 0:2:1, default 2 control[0]: 0x98091a White Balance Temperature, 0:10000:10, default 4000 control[0]: 0x98091b Sharpness, 0:255:1, default 24 control[0]: 0x98091c Backlight Compensation, 0:1:1, default 1 control[0]: 0x9a0901 Exposure, Auto, 0:3:1, default 3 control[0]: 0x9a0902 Exposure (Absolute), 1:10000:1, default 166 control[0]: 0x9a0903 Exposure, Auto Priority, 0:1:1, default 0 resolutions of format(2) = 19 frame rates of 1º resolution=6 Def. Res: 0 numb. fps:6 --------------------------------------- device #0 Name = Intel 82801DB-ICH4: Intel 82801DB-ICH4 (hw:0,0) Host API = ALSA Max inputs = 2, Max outputs = 2 Def. low input latency = 0.012 Def. low output latency = 0.012 Def. high input latency = 0.046 Def. high output latency = 0.046 Def. sample rate = 44100.00 --------------------------------------- device #1 Name = Intel 82801DB-ICH4: Intel 82801DB-ICH4 - MIC ADC (hw:0,1) Host API = ALSA Max inputs = 2, Max outputs = 0 Def. low input latency = 0.011 Def. low output latency = -1.000 Def. high input latency = 0.043 Def. high output latency = -1.000 Def. sample rate = 48000.00 --------------------------------------- device #2 Name = Intel 82801DB-ICH4: Intel 82801DB-ICH4 - MIC2 ADC (hw:0,2) Host API = ALSA Max inputs = 2, Max outputs = 0 Def. low input latency = 0.011 Def. low output latency = -1.000 Def. high input latency = 0.043 Def. high output latency = -1.000 Def. sample rate = 48000.00 --------------------------------------- device #3 Name = Intel 82801DB-ICH4: Intel 82801DB-ICH4 - ADC2 (hw:0,3) Host API = ALSA Max inputs = 2, Max outputs = 0 Def. low input latency = 0.011 Def. low output latency = -1.000 Def. high input latency = 0.043 Def. high output latency = -1.000 Def. sample rate = 48000.00 --------------------------------------- device #4 Name = Intel 82801DB-ICH4: Intel 82801DB-ICH4 - IEC958 (hw:0,4) Host API = ALSA Max inputs = 0, Max outputs = 2 Def. low input latency = -1.000 Def. low output latency = 0.011 Def. high input latency = -1.000 Def. high output latency = 0.043 Def. sample rate = 48000.00 --------------------------------------- device #5 Name = USB Device 0x46d:0x825: USB Audio (hw:1,0) Host API = ALSA Max inputs = 1, Max outputs = 0 Def. low input latency = 0.011 Def. low output latency = -1.000 Def. high input latency = 0.043 Def. high output latency = -1.000 Def. sample rate = 48000.00 --------------------------------------- device #6 Name = front Host API = ALSA Max inputs = 0, Max outputs = 2 Def. low input latency = -1.000 Def. low output latency = 0.012 Def. high input latency = -1.000 Def. high output latency = 0.046 Def. sample rate = 44100.00 --------------------------------------- device #7 Name = iec958 Host API = ALSA Max inputs = 0, Max outputs = 2 Def. low input latency = -1.000 Def. low output latency = 0.011 Def. high input latency = -1.000 Def. high output latency = 0.043 Def. sample rate = 48000.00 --------------------------------------- device #8 Name = spdif Host API = ALSA Max inputs = 0, Max outputs = 2 Def. low input latency = -1.000 Def. low output latency = 0.011 Def. high input latency = -1.000 Def. high output latency = 0.043 Def. sample rate = 48000.00 --------------------------------------- device #9 Name = pulse Host API = ALSA Max inputs = 32, Max outputs = 32 Def. low input latency = 0.012 Def. low output latency = 0.012 Def. high input latency = 0.046 Def. high output latency = 0.046 Def. sample rate = 44100.00 --------------------------------------- device #10 Name = dmix Host API = ALSA Max inputs = 0, Max outputs = 2 Def. low input latency = -1.000 Def. low output latency = 0.043 Def. high input latency = -1.000 Def. high output latency = 0.043 Def. sample rate = 48000.00 --------------------------------------- device #11 [ Default Input, Default Output ] Name = default Host API = ALSA Max inputs = 32, Max outputs = 32 Def. low input latency = 0.012 Def. low output latency = 0.012 Def. high input latency = 0.046 Def. high output latency = 0.046 Def. sample rate = 44100.00 ---------------------------------------------- SampleRate:0 Channels:0 Video driver: x11 A window manager is available VIDIOC_S_EXT_CTRLS for multiple controls failed (error -1) using VIDIOC_S_CTRL for user class controls control(0x0098091a) "White Balance Temperature" failed to set (error -1) VIDIOC_S_EXT_CTRLS for multiple controls failed (error -1) using VIDIOC_S_EXT_CTRLS on single controls for class: 0x009a0000 control(0x009a0902) "Exposure (Absolute)" failed to set (error -1) VIDIOC_S_EXT_CTRLS for multiple controls failed (error -1) using VIDIOC_S_CTRL for user class controls control(0x0098091a) "White Balance Temperature" failed to set (error -1) VIDIOC_S_EXT_CTRLS for multiple controls failed (error -1) using VIDIOC_S_EXT_CTRLS on single controls for class: 0x009a0000 control(0x009a0902) "Exposure (Absolute)" failed to set (error -1) Cap Video toggled: 1 (/home/sijar/Videos/Webcam) 25371756K bytes free on a total of 39908968K (used: 36 %) treshold=51200K using audio codec: 0x0055 Audio frame size is 1152 samples for selected codec IO thread started...OK [libx264 @ 0x8cbd8b0]using cpu capabilities: MMX2 SSE2 Cache64 [libx264 @ 0x8cbd8b0]profile Baseline, level 3.0 [libx264 @ 0x8cbd8b0]non-strictly-monotonic PTS shift sound by -9 ms shift sound by -9 ms shift sound by -9 ms AUDIO: droping audio data AUDIO: droping audio data AUDIO: droping audio data AUDIO: droping audio data AUDIO: droping audio data ... repeats a couple of times ... AUDIO: droping audio data (/home/sijar/Videos/Webcam) 25371748K bytes free on a total of 39908968K (used: 36 %) treshold=51200K AUDIO: droping audio data AUDIO: droping audio data ... repeats a couple of times ... Cap Video toggled: 0 Shuting Down IO Thread AUDIO: droping audio data stop= 4426644744000 start=4416533023000 VIDEO: 146 frames in 10111.000000 ms = 14.439719 fps Stoping audio stream Closing audio stream... close avi Last message repeated 145 times [libx264 @ 0x8cbd8b0]frame I:2 Avg QP:14.10 size: 24492 [libx264 @ 0x8cbd8b0]frame P:103 Avg QP:16.06 size: 20715 [libx264 @ 0x8cbd8b0]mb I I16..4: 48.4% 0.0% 51.6% [libx264 @ 0x8cbd8b0]mb P I16..4: 57.5% 0.0% 0.0% P16..4: 40.2% 0.0% 0.0% 0.0% 0.0% skip: 2.3% [libx264 @ 0x8cbd8b0]final ratefactor: 62.05 [libx264 @ 0x8cbd8b0]coded y,uvDC,uvAC intra: 79.7% 92.2% 68.4% inter: 62.4% 87.5% 48.0% [libx264 @ 0x8cbd8b0]i16 v,h,dc,p: 23% 17% 41% 19% [libx264 @ 0x8cbd8b0]i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 30% 24% 26% 2% 5% 3% 3% 3% 4% [libx264 @ 0x8cbd8b0]i8c dc,h,v,p: 53% 20% 23% 4% [libx264 @ 0x8cbd8b0]ref P L0: 63.0% 37.0% [libx264 @ 0x8cbd8b0]kb/s:-0.00 total frames encoded: 0 total audio frames encoded: 0 IO thread finished...OK IO Thread finished enabling controls Cap Video toggled: 1 (/home/sijar/Videos/Webcam) 25379744K bytes free on a total of 39908968K (used: 36 %) treshold=51200K using audio codec: 0x0055 Audio frame size is 1152 samples for selected codec IO thread started...OK [libx264 @ 0x8cfba20]using cpu capabilities: MMX2 SSE2 Cache64 [libx264 @ 0x8cfba20]profile Baseline, level 3.0 [libx264 @ 0x8cfba20]non-strictly-monotonic PTS shift sound by -236 ms shift sound by -236 ms shift sound by -236 ms (/home/sijar/Videos/Webcam) 25377044K bytes free on a total of 39908968K (used: 36 %) treshold=51200K (/home/sijar/Videos/Webcam) 25373408K bytes free on a total of 39908968K (used: 36 %) treshold=51200K AUDIO: droping audio data AUDIO: droping audio data AUDIO: droping audio data AUDIO: droping audio data AUDIO: droping audio data AUDIO: droping audio data ... repeats a couple of times ... (/home/sijar/Videos/Webcam) 25370696K bytes free on a total of 39908968K (used: 36 %) treshold=51200K AUDIO: droping audio data AUDIO: droping audio data AUDIO: droping audio data ... repeats a couple of times ... (/home/sijar/Videos/Webcam) 25367680K bytes free on a total of 39908968K (used: 36 %) treshold=51200K (/home/sijar/Videos/Webcam) 25364052K bytes free on a total of 39908968K (used: 36 %) treshold=51200K (/home/sijar/Videos/Webcam) 25360312K bytes free on a total of 39908968K (used: 36 %) treshold=51200K (/home/sijar/Videos/Webcam) 25356628K bytes free on a total of 39908968K (used: 36 %) treshold=51200K (/home/sijar/Videos/Webcam) 25352908K bytes free on a total of 39908968K (used: 36 %) treshold=51200K (/home/sijar/Videos/Webcam) 25349316K bytes free on a total of 39908968K (used: 36 %) treshold=51200K (/home/sijar/Videos/Webcam) 25345552K bytes free on a total of 39908968K (used: 36 %) treshold=51200K (/home/sijar/Videos/Webcam) 25341828K bytes free on a total of 39908968K (used: 36 %) treshold=51200K (/home/sijar/Videos/Webcam) 25338092K bytes free on a total of 39908968K (used: 36 %) treshold=51200K (/home/sijar/Videos/Webcam) 25334412K bytes free on a total of 39908968K (used: 36 %) treshold=51200K Cap Video toggled: 0 Shuting Down IO Thread stop= 4708817235000 start=4578624714000 VIDEO: 1604 frames in 130192.000000 ms = 12.320265 fps Stoping audio stream Closing audio stream... close avi Last message repeated 1603 times [libx264 @ 0x8cfba20]frame I:16 Avg QP:14.78 size: 42627 [libx264 @ 0x8cfba20]frame P:1547 Avg QP:16.44 size: 28599 [libx264 @ 0x8cfba20]mb I I16..4: 21.6% 0.0% 78.4% [libx264 @ 0x8cfba20]mb P I16..4: 28.1% 0.0% 0.0% P16..4: 70.5% 0.0% 0.0% 0.0% 0.0% skip: 1.4% [libx264 @ 0x8cfba20]final ratefactor: 88.17 [libx264 @ 0x8cfba20]coded y,uvDC,uvAC intra: 74.4% 95.8% 83.2% inter: 75.2% 94.6% 69.2% [libx264 @ 0x8cfba20]i16 v,h,dc,p: 27% 17% 40% 16% [libx264 @ 0x8cfba20]i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 25% 25% 21% 3% 6% 4% 5% 4% 7% [libx264 @ 0x8cfba20]i8c dc,h,v,p: 61% 18% 18% 4% [libx264 @ 0x8cfba20]ref P L0: 64.0% 36.0% [libx264 @ 0x8cfba20]kb/s:-0.00 total frames encoded: 0 total audio frames encoded: 0 IO thread finished...OK IO Thread finished enabling controls Shuting Down Thread Thread terminated... cleaning Thread allocations: 100% SDL Quit Video Thread finished write /home/sijar/.guvcviewrc OK free audio mutex closed v4l2 strutures free controls free controls - vidState cleaned allocations - 100% Closing portaudio ...OK Closing GTK... OK

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  • How to Run Low-Cost Minecraft on a Raspberry Pi for Block Building on the Cheap

    - by Jason Fitzpatrick
    We’ve shown you how to run your own blocktastic personal Minecraft server on a Windows/OSX box, but what if you crave something lighter weight, more energy efficient, and always ready for your friends? Read on as we turn a tiny Raspberry Pi machine into a low-cost Minecraft server you can leave on 24/7 for around a penny a day. Why Do I Want to Do This? There’s two aspects to this tutorial, running your own Minecraft server and specifically running that Minecraft server on a Raspberry Pi. Why would you want to run your own Minecraft server? It’s a really great way to extend and build upon the Minecraft play experience. You can leave the server running when you’re not playing so friends and family can join and continue building your world. You can mess around with game variables and introduce mods in a way that isn’t possible when you’re playing the stand-alone game. It also gives you the kind of control over your multiplayer experience that using public servers doesn’t, without incurring the cost of hosting a private server on a remote host. While running a Minecraft server on its own is appealing enough to a dedicated Minecraft fan, running it on the Raspberry Pi is even more appealing. The tiny little Pi uses so little resources that you can leave your Minecraft server running 24/7 for a couple bucks a year. Aside from the initial cost outlay of the Pi, an SD card, and a little bit of time setting it up, you’ll have an always-on Minecraft server at a monthly cost of around one gumball. What Do I Need? For this tutorial you’ll need a mix of hardware and software tools; aside from the actual Raspberry Pi and SD card, everything is free. 1 Raspberry Pi (preferably a 512MB model) 1 4GB+ SD card This tutorial assumes that you have already familiarized yourself with the Raspberry Pi and have installed a copy of the Debian-derivative Raspbian on the device. If you have not got your Pi up and running yet, don’t worry! Check out our guide, The HTG Guide to Getting Started with Raspberry Pi, to get up to speed. Optimizing Raspbian for the Minecraft Server Unlike other builds we’ve shared where you can layer multiple projects over one another (e.g. the Pi is more than powerful enough to serve as a weather/email indicator and a Google Cloud Print server at the same time) running a Minecraft server is a pretty intense operation for the little Pi and we’d strongly recommend dedicating the entire Pi to the process. Minecraft seems like a simple game, with all its blocky-ness and what not, but it’s actually a pretty complex game beneath the simple skin and required a lot of processing power. As such, we’re going to tweak the configuration file and other settings to optimize Rasbian for the job. The first thing you’ll need to do is dig into the Raspi-Config application to make a few minor changes. If you’re installing Raspbian fresh, wait for the last step (which is the Raspi-Config), if you already installed it, head to the terminal and type in “sudo raspi-config” to launch it again. One of the first and most important things we need to attend to is cranking up the overclock setting. We need all the power we can get to make our Minecraft experience enjoyable. In Raspi-Config, select option number 7 “Overclock”. Be prepared for some stern warnings about overclocking, but rest easy knowing that overclocking is directly supported by the Raspberry Pi foundation and has been included in the configuration options since late 2012. Once you’re in the actual selection screen, select “Turbo 1000MhHz”. Again, you’ll be warned that the degree of overclocking you’ve selected carries risks (specifically, potential corruption of the SD card, but no risk of actual hardware damage). Click OK and wait for the device to reset. Next, make sure you’re set to boot to the command prompt, not the desktop. Select number 3 “Enable Boot to Desktop/Scratch”  and make sure “Console Text console” is selected. Back at the Raspi-Config menu, select number 8 “Advanced Options’. There are two critical changes we need to make in here and one option change. First, the critical changes. Select A3 “Memory Split”: Change the amount of memory available to the GPU to 16MB (down from the default 64MB). Our Minecraft server is going to ruin in a GUI-less environment; there’s no reason to allocate any more than the bare minimum to the GPU. After selecting the GPU memory, you’ll be returned to the main menu. Select “Advanced Options” again and then select A4 “SSH”. Within the sub-menu, enable SSH. There is very little reason to keep this Pi connected to a monitor and keyboard, by enabling SSH we can remotely access the machine from anywhere on the network. Finally (and optionally) return again to the “Advanced Options” menu and select A2 “Hostname”. Here you can change your hostname from “raspberrypi” to a more fitting Minecraft name. We opted for the highly creative hostname “minecraft”, but feel free to spice it up a bit with whatever you feel like: creepertown, minecraft4life, or miner-box are all great minecraft server names. That’s it for the Raspbian configuration tab down to the bottom of the main screen and select “Finish” to reboot. After rebooting you can now SSH into your terminal, or continue working from the keyboard hooked up to your Pi (we strongly recommend switching over to SSH as it allows you to easily cut and paste the commands). If you’ve never used SSH before, check out how to use PuTTY with your Pi here. Installing Java on the Pi The Minecraft server runs on Java, so the first thing we need to do on our freshly configured Pi is install it. Log into your Pi via SSH and then, at the command prompt, enter the following command to make a directory for the installation: sudo mkdir /java/ Now we need to download the newest version of Java. At the time of this publication the newest release is the OCT 2013 update and the link/filename we use will reflect that. Please check for a more current version of the Linux ARMv6/7 Java release on the Java download page and update the link/filename accordingly when following our instructions. At the command prompt, enter the following command: sudo wget --no-check-certificate http://www.java.net/download/jdk8/archive/b111/binaries/jdk-8-ea-b111-linux-arm-vfp-hflt-09_oct_2013.tar.gz Once the download has finished successfully, enter the following command: sudo tar zxvf jdk-8-ea-b111-linux-arm-vfp-hflt-09_oct_2013.tar.gz -C /opt/ Fun fact: the /opt/ directory name scheme is a remnant of early Unix design wherein the /opt/ directory was for “optional” software installed after the main operating system; it was the /Program Files/ of the Unix world. After the file has finished extracting, enter: sudo /opt/jdk1.8.0/bin/java -version This command will return the version number of your new Java installation like so: java version "1.8.0-ea" Java(TM) SE Runtime Environment (build 1.8.0-ea-b111) Java HotSpot(TM) Client VM (build 25.0-b53, mixed mode) If you don’t see the above printout (or a variation thereof if you’re using a newer version of Java), try to extract the archive again. If you do see the readout, enter the following command to tidy up after yourself: sudo rm jdk-8-ea-b111-linux-arm-vfp-hflt-09_oct_2013.tar.gz At this point Java is installed and we’re ready to move onto installing our Minecraft server! Installing and Configuring the Minecraft Server Now that we have a foundation for our Minecraft server, it’s time to install the part that matter. We’ll be using SpigotMC a lightweight and stable Minecraft server build that works wonderfully on the Pi. First, grab a copy of the the code with the following command: sudo wget http://ci.md-5.net/job/Spigot/lastSuccessfulBuild/artifact/Spigot-Server/target/spigot.jar This link should remain stable over time, as it points directly to the most current stable release of Spigot, but if you have any issues you can always reference the SpigotMC download page here. After the download finishes successfully, enter the following command: sudo /opt/jdk1.8.0/bin/java -Xms256M -Xmx496M -jar /home/pi/spigot.jar nogui Note: if you’re running the command on a 256MB Pi change the 256 and 496 in the above command to 128 and 256, respectively. Your server will launch and a flurry of on-screen activity will follow. Be prepared to wait around 3-6 minutes or so for the process of setting up the server and generating the map to finish. Future startups will take much less time, around 20-30 seconds. Note: If at any point during the configuration or play process things get really weird (e.g. your new Minecraft server freaks out and starts spawning you in the Nether and killing you instantly), use the “stop” command at the command prompt to gracefully shutdown the server and let you restart and troubleshoot it. After the process has finished, head over to the computer you normally play Minecraft on, fire it up, and click on Multiplayer. You should see your server: If your world doesn’t popup immediately during the network scan, hit the Add button and manually enter the address of your Pi. Once you connect to the server, you’ll see the status change in the server status window: According to the server, we’re in game. According to the actual Minecraft app, we’re also in game but it’s the middle of the night in survival mode: Boo! Spawning in the dead of night, weaponless and without shelter is no way to start things. No worries though, we need to do some more configuration; no time to sit around and get shot at by skeletons. Besides, if you try and play it without some configuration tweaks first, you’ll likely find it quite unstable. We’re just here to confirm the server is up, running, and accepting incoming connections. Once we’ve confirmed the server is running and connectable (albeit not very playable yet), it’s time to shut down the server. Via the server console, enter the command “stop” to shut everything down. When you’re returned to the command prompt, enter the following command: sudo nano server.properties When the configuration file opens up, make the following changes (or just cut and paste our config file minus the first two lines with the name and date stamp): #Minecraft server properties #Thu Oct 17 22:53:51 UTC 2013 generator-settings= #Default is true, toggle to false allow-nether=false level-name=world enable-query=false allow-flight=false server-port=25565 level-type=DEFAULT enable-rcon=false force-gamemode=false level-seed= server-ip= max-build-height=256 spawn-npcs=true white-list=false spawn-animals=true texture-pack= snooper-enabled=true hardcore=false online-mode=true pvp=true difficulty=1 player-idle-timeout=0 gamemode=0 #Default 20; you only need to lower this if you're running #a public server and worried about loads. max-players=20 spawn-monsters=true #Default is 10, 3-5 ideal for Pi view-distance=5 generate-structures=true spawn-protection=16 motd=A Minecraft Server In the server status window, seen through your SSH connection to the pi, enter the following command to give yourself operator status on your Minecraft server (so that you can use more powerful commands in game, without always returning to the server status window). op [your minecraft nickname] At this point things are looking better but we still have a little tweaking to do before the server is really enjoyable. To that end, let’s install some plugins. The first plugin, and the one you should install above all others, is NoSpawnChunks. To install the plugin, first visit the NoSpawnChunks webpage and grab the download link for the most current version. As of this writing the current release is v0.3. Back at the command prompt (the command prompt of your Pi, not the server console–if your server is still active shut it down) enter the following commands: cd /home/pi/plugins sudo wget http://dev.bukkit.org/media/files/586/974/NoSpawnChunks.jar Next, visit the ClearLag plugin page, and grab the latest link (as of this tutorial, it’s v2.6.0). Enter the following at the command prompt: sudo wget http://dev.bukkit.org/media/files/743/213/Clearlag.jar Because the files aren’t compressed in a .ZIP or similar container, that’s all there is to it: the plugins are parked in the plugin directory. (Remember this for future plugin downloads, the file needs to be whateverplugin.jar, so if it’s compressed you need to uncompress it in the plugin directory.) Resart the server: sudo /opt/jdk1.8.0/bin/java -Xms256M -Xmx496M -jar /home/pi/spigot.jar nogui Be prepared for a slightly longer startup time (closer to the 3-6 minutes and much longer than the 30 seconds you just experienced) as the plugins affect the world map and need a minute to massage everything. After the spawn process finishes, type the following at the server console: plugins This lists all the plugins currently active on the server. You should see something like this: If the plugins aren’t loaded, you may need to stop and restart the server. After confirming your plugins are loaded, go ahead and join the game. You should notice significantly snappier play. In addition, you’ll get occasional messages from the plugins indicating they are active, as seen below: At this point Java is installed, the server is installed, and we’ve tweaked our settings for for the Pi.  It’s time to start building with friends!     

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  • SQL SERVER – Weekly Series – Memory Lane – #003

    - by pinaldave
    Here is the list of curetted articles of SQLAuthority.com across all these years. Instead of just listing all the articles I have selected a few of my most favorite articles and have listed them here with additional notes below it. Let me know which one of the following is your favorite article from memory lane. 2006 This was the first year of my blogging and lots of new things I was learning as I go. I was indeed an infant in blogging a few years ago. However, as time passed by I have learned a lot. This year was year of experiments and new learning. 2007 Working as a full time DBA I often encoutered various errors and I started to learn how to avoid those error and document the same. ERROR Msg 5174 Each file size must be greater than or equal to 512 KB Whenever I see this error I wonder why someone is trying to attempt a database which is extremely small. Anyway, it does not matter what I think I keep on seeing this error often in industries. Anyway the solution of the error is equally interesting – just created larger database. Dilbert Humor This was very first encounter with database humor and I started to love it. It does not matter how many time we read this cartoon it does not get old. Generate Script with Data from Database – Database Publishing Wizard Generating schema script with data is one of the most frequently performed tasks among SQL Server Data Professionals. There are many ways to do the same. In the above article I demonstrated that how we can use the Database Publishing Wizard to accomplish the same. It was new to me at that time but I have not seen much of the adoption of the same still in the industry. Here is one of my videos where I demonstrate how we can generate data with schema. 2008 Delete Backup History – Cleanup Backup History Deleting backup history is important too but should be done carefully. If this is not carried out at regular interval there is good chance that MSDB will be filled up with all the old history. Every organization is different. Some would like to keep the history for 30 days and some for a year but there should be some limit. One should regularly archive the database backup history. South Asia MVP Open Days 2008 This was my very first year Microsoft MVP. I had Indeed big blast at the event and the fun was incredible. After this event I have attended many different MVP events but the fun and learning this particular event presented was amazing and just like me many others are not able to forget the same. Here are other links related to the event: South Asia MVP Open Day 2008 – Goa South Asia MVP Open Day 2008 – Goa – Day 1 South Asia MVP Open Day 2008 – Goa – Day 2 South Asia MVP Open Day 2008 – Goa – Day 3 2009 Enable or Disable Constraint  This is very simple script but I personally keep on forgetting it so I had blogged it. Till today, I keep on referencing this again and again as sometime a very little thing is hard to remember. Policy Based Management – Create, Evaluate and Fix Policies This article will cover the most spectacular feature of SQL 2008 – Policy-based management and how the configuration of SQL Server with policy-based management architecture can make a powerful difference. Policy based management is loaded with several advantages. It can help you implement various policies for reliable configuration of the system. It also provides additional administrative assistance to DBAs and helps them effortlessly manage various tasks of SQL Server across the enterprise. SQLPASS 2009 – My Very First SQPASS Experience Just Brilliant! I never had an experience such a thing in my life. SQL SQL and SQL – all around SQL! I am listing my own reasons here in order of importance to me. Networking with SQL fellows and experts Putting face to the name or avatar Learning and improving my SQL skills Understanding the structure of the largest SQL Server Professional Association Attending my favorite training sessions Since last time I have never missed a single time this event. This event is my favorite event and something keeps me going. Here are additional post related SQLPASS 2009. SQL PASS Summit, Seattle 2009 – Day 1 SQL PASS Summit, Seattle 2009 – Day 2 SQL PASS Summit, Seattle 2009 – Day 3 SQL PASS Summit, Seattle 2009 – Day 4 2010 Get All the Information of Database using sys.databases Even though we believe that we know everything about our database, we do not know a lot of things about our database. This little script enables us to know so many details about databases which we may not be familiar with. Run this on your server today and see how much you know your database. Reducing CXPACKET Wait Stats for High Transactional Database While engaging in a performance tuning consultation for a client, a situation occurred where they were facing a lot of CXPACKET Waits Stats. The client asked me if I could help them reduce this huge number of wait stats. I usually receive this kind of request from other client as well, but the important thing to understand is whether this question has any merits or benefits, or not. I discusses the same in this article – a bit long but insightful for sure. Error related to Database in Use There are so many database management operations in SQL Server which requires exclusive access to the database and it is not always possible to get it. When any database is online in SQL Server it either applications or system thread often accesses them. This means database can’t have exclusive access and the operations which required this access throws an error. There is very easy method to overcome this minor issue – a single line script can give you exclusive access to the database. Difference between DATETIME and DATETIME2 Developers have found the root reason of the problem when dealing with Date Functions – when data time values are converted (implicit or explicit) between different data types, which would lose some precision, so the result cannot match each other as expected. In this blog post I go over very interesting details and difference between DATETIME and DATETIME2 History of SQL Server Database Encryption I recently met Michael Coles and Rodeney Landrum the author of one of the kind book Expert SQL Server 2008 Encryption at SQLPASS in Seattle. During the conversation we ended up how Microsoft is evolving encryption technology. The same discussion lead to talking about history of encryption tools in SQL Server. Michale pointed me to page 18 of his book of encryption. He explicitly gave me permission to re-produce relevant part of history from his book. 2011 Functions FIRST_VALUE and LAST_VALUE with OVER clause and ORDER BY Some time an interesting feature and smart audience make a total difference in places. From last two days, I have been writing on SQL Server 2012 feature FIRST_VALUE and LAST_VALUE. I created a puzzle which was very interesting and got many people attempt to resolve it. It was based on following two articles: Introduction to FIRST_VALUE and LAST_VALUE Introduction to FIRST_VALUE and LAST_VALUE with OVER clause I even provided the hint about how one can solve this problem. The best part was many people solved the problem without using hints! Try your luck!  A Real Story of Book Getting ‘Out of Stock’ to A 25% Discount Story Available This is a great problem and everybody would love to have it. We had it and we loved it. Our book got out of stock in 48 hours of releasing and stocks were empty. We faced many issues and learned many valuable lessons. Some we were able to avoid in the future and some we are still facing it as those problems have no solutions. However, since that day – our books never gone out of stock. This inspiring learning story for us and I am confident that you will love to read it as well. Introduction to LEAD and LAG – Analytic Functions Introduced in SQL Server 2012 SQL Server 2012 introduces new analytical function LEAD() and LAG(). This function accesses data from a subsequent row (for lead) and previous row (for lag) in the same result set without the use of a self-join . It will be very difficult to explain this in words so I will attempt small example to explain you this function. I had a fantastic time writing this blog post and I am very confident when you read it, you will like the same. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Memory Lane, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • SQL Cruise Alaska 2011

    - by Grant Fritchey
    I had the extreme good fortune to get sent on the last SQL Cruise to Alaska. I love my job. In case you don't what this is, SQL Cruise is a trip on a cruise ship during which you get to attend classes while on the boat, learning all about SQL Server and related topics as well as network with the instructors and the other Cruisers. Frankly, it's amazing. Classes ran from Monday, 5/30, to Saturday, 6/4. The networking was constant, between classes, at night on cruise ship, out on excursions in Alaskan rainforests and while snorkeling in ocean waters. Here's a run down of the experience from my point of view. Because I couldn't travel out 2 days early, I missed the BBQ that occurred the day before the cruise when many of the Cruisers received their swag bags. Some of that swag came from Red Gate. I researched what was useful on a cruise like this and purchased small flashlights and binoculars for all the Cruisers. The flashlights were because, depending on your cabin, ships can be very dark. The binoculars were so that the cruisers could watch all the beautiful landscape as it flowed by. I would have liked to have been there when the bags were opened, but I heard from several people that they appreciated the gifts. Cruisers "In" the hot tub. Pictured: Marjory Woody, Michele Grondin, Kyle Brandt, Grant Fritchey, John Halunen Sunday I went to board the ship with my wife. We had a bit of an adventure because I messed up our documents. It all worked out and we got on board to meet up at the back of the boat at one of the outdoor bars with the other Cruisers, thanks to tweets letting everyone know where to go. That was the end of electronic coordination on the trip (connectivity in Alaska was horrible for everyone except AT&T). The Cruisers were a great bunch of people and it was a real honor to meet them and get to spend time with them. After everyone settled into their cabins, our very first activity was a contest, sponsored by Red Gate. The Cruisers, in an effort to get to know each other and the ship, were required to go all over taking various photographs, some of them hilarious. The winning team of three would all win prizes. Some of the significant others helped out and I tagged along with a team that tied for first but lost the coin toss. The winning team consisted of Christina Leo (blog|twitter), Ryan Malcom (twitter), Neil Hambly (blog|twitter). They then had to do math and identify the cabin with the lowest prime number, oh, and get a picture of it and be the first to get back up to the bar where we were waiting. Christina came in first and very happily carried home an Ipad2. Ryan won a 1TB portable hard drive and Neil won a wireless mouse (picture below, note my special SQL Server Central Friday Shirt. Thanks Steve (blog|twitter)). Winners: Christina Leo, Neil Hambly, Ryan Malcolm. Just Lucky: Grant Fritchey Monday morning classes started. Buck Woody (blog|twitter) was a special guest speaker on this cruise. His theme was "Three C's on the High Seas: Career, Communication and Cloud." The first session was all on Career. I'm not going to type out all my notes from the session, but let's just say, if you get the chance to hear Buck talk about how to manage your career, I suggest you attend. I have a ton of blog posts that I'll be putting together over the next several months (yes, months) both here and over on ScaryDBA. I also have a bunch of work I'm going to be doing to get my career performance bumped up a notch or two (and let's face it, that won't be easy). Later on Monday, Tim Ford (blog|twitter) did a session on DMOs. Specifically the session was on Tim's Period Table of DMOs that he has put together, and how to use some of the more interesting DMOs in your day to day job. It was a great session, packed with good information. Next, Brent Ozar (blog|twitter) did a session on how to monitor and guide SAN configuration for the DBA that doesn't have access to the SAN. That was some seriously useful information. Tuesday morning we only had a single class. Kendra Little (blog|twitter) taught us all about "No Lock for Yes Fun".  It was all about the different transaction isolation levels and how they work. There is so often confusion in this area and Kendra does a great job in clarifying the information. Also, she tosses in her excellent drawings to liven up the presentation. Then it was excursion time in Juneau. My wife and I, along with several other Cruisers, took a hike up around the Mendenhall Glacier. It was absolutely beautiful weather and walking through the Alaskan rain forest was a treat. Our guide, Jason, was a great guy and it was a good day of hiking. Wednesday was an all day excursion in Skagway. My wife and I took the "Ghost and Good Time Girls" walking tour that ended up at a bar that used to be a brothel, the Red Onion. It was a great history of the town. We went back out and hit a few museums and exhibits. We also hiked up the side of the mountain to see the Dewey Lake and some great views of the town. Finally we hiked out to the far side of town to see the Gold Rush cemetery. Hiking done we went back to the boat and had a quiet dinner on our own. Thursday we cruised through Glacier Bay and saw at least four different glaciers including sitting next to the Marjory Glacier for  about an hour. It was amazing. Then it got better. We went into class with Buck again, this time to talk about Communication. Again, I've got pages of notes that I'm going to be referring back to for some time to come. This was an excellent opportunity to learn. Snorkelers: Nicole Bertrand, Aaron Bertrand, Grant Fritchey, Neil Hambly, Christina Leo, John Robel, Yanni Robel, Tim Ford Friday we pulled into Ketchikan. A bunch of us went snorkeling. Yes, snorkeling. Yes, in Alaska. Yes, snorkeling in the ocean in Alaska. It was fantastic. They had us put on 7mm thick wet suits (an adventure all by itself) so it was basically warm the entire time we were in the water (except for the occasional squirt of cold water down my back). Before we got in the water a bald eagle flew up and landed about 15 feet in front of us, which was just an incredible event. Then our guide pointed out about 14 other eagles in the area, hanging out in the trees. Wow! The water was pretty clear and there was a ton of things to see. That was absolutely a blast. Back on the boat I presented a session called Execution Plans: The Deep Dive (note the nautical theme). It seemed to go over well and I had several good questions come out of the session that will lead to new blog posts. After I presented, it was Aaron Bertrand's (blog|twitter) turn. He did a session on "What's New in Denali" that provided a lot of great information. He was able to incorporate new things straight out of Tech-Ed, so this was expanded beyond his usual presentation. The man really knows what he's talking about and communicates it well. Saturday we were travelling so there was time for a bunch of classes. Jeremiah Peschka (blog|twitter) did a great overview of some of the NoSQL databases and what they should be used for. The session was called "The Database is Dead" but it was really about how there are specific uses for these databases that SQL Server doesn't fill, but also that these databases can't replace SQL Server in other areas. Again, good material. Brent Ozar presented again with a session on Defensive Indexing. It was an overview of how indexes work and a deep dive into how to apply them appropriately in your databases to better support access. A good session, as you would expect. Then we pulled into Victoria, BC, in Canada and had a nice dinner with several of the Cruisers, including Denny Cherry (blog|twitter). After that it was back to Seattle on Sunday. By the way, the Science Fiction Museum in Seattle isn't a Science Fiction Museum any more. I was very disappointed to discover this. Overall, it was a great experience. I'm extremely appreciative of Red Gate for sending me and for Tim, Brent, Kendra and Jeremiah for having me. The other Cruisers were all amazing people and it was an honor & privilege to meet them and spend time with them. While this was a seriously fun time, it was also a very serious training opportunity with solid information coming from seasoned industry pros.

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  • XNA 3D model collision is inaccurate

    - by Daniel Lopez
    I am creating a classic game in 3d that deals with asteriods and you have to shoot them and avoid being hit from them. I can generate the asteroids just fine and the ship can shoot bullets just fine. But the asteroids always hit the ship even it doesn't look they are even close. I know 2D collision very well but not 3D so can someone please shed some light to my problem. Thanks in advance. Code For ModelRenderer: using System; using System.Collections.Generic; using System.Linq; using Microsoft.Xna.Framework; using Microsoft.Xna.Framework.Audio; using Microsoft.Xna.Framework.Content; using Microsoft.Xna.Framework.GamerServices; using Microsoft.Xna.Framework.Graphics; using Microsoft.Xna.Framework.Input; using Microsoft.Xna.Framework.Media; namespace _3D_Asteroids { class ModelRenderer { private float aspectratio; private Model model; private Vector3 camerapos; private Vector3 modelpos; private Matrix rotationy; float radiansy = 0; private bool isalive; public ModelRenderer(Model m, float AspectRatio, Vector3 initial_pos, Vector3 initialcamerapos) { isalive = true; model = m; if (model.Meshes.Count == 0) { throw new Exception("Invalid model because it contains zero meshes!"); } modelpos = initial_pos; camerapos = initialcamerapos; aspectratio = AspectRatio; return; } public float RadiusOfSphere { get { return model.Meshes[0].BoundingSphere.Radius; } } public BoundingBox BoxBounds { get { return BoundingBox.CreateFromSphere(model.Meshes[0].BoundingSphere); } } public BoundingSphere SphereBounds { get { return model.Meshes[0].BoundingSphere; } } public Vector3 CameraPosition { set { camerapos = value; } get { return camerapos; } } public bool IsAlive { get { return isalive; } } public Vector3 ModelPosition { set { modelpos = value; } get { return modelpos; } } public void RotateY(float radians) { radiansy += radians; rotationy = Matrix.CreateRotationY(radiansy); } public Matrix RotationY { set { rotationy = value; } get { return rotationy; } } public float AspectRatio { set { aspectratio = value; } get { return aspectratio; } } public void Kill() { isalive = false; } public void Draw(float scale) { Matrix world; if (rotationy == new Matrix(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)) { world = Matrix.CreateScale(scale) * Matrix.CreateTranslation(modelpos); } else { world = rotationy * Matrix.CreateScale(scale) * Matrix.CreateTranslation(modelpos); } Matrix view = Matrix.CreateLookAt(camerapos, Vector3.Zero, Vector3.Up); Matrix projection = Matrix.CreatePerspectiveFieldOfView(MathHelper.ToRadians(45.0f), this.AspectRatio, 1f, 100000f); foreach (ModelMesh mesh in model.Meshes) { foreach (BasicEffect effect in mesh.Effects) { effect.World = world; effect.View = view; effect.Projection = projection; } mesh.Draw(); } } public void Draw() { Matrix world; if (rotationy == new Matrix(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)) { world = Matrix.CreateTranslation(modelpos); } else { world = rotationy * Matrix.CreateTranslation(modelpos); } Matrix view = Matrix.CreateLookAt(camerapos, Vector3.Zero, Vector3.Up); Matrix projection = Matrix.CreatePerspectiveFieldOfView(MathHelper.ToRadians(45.0f), this.AspectRatio, 1f, 100000f); foreach (ModelMesh mesh in model.Meshes) { foreach (BasicEffect effect in mesh.Effects) { effect.World = world; effect.View = view; effect.Projection = projection; } mesh.Draw(); } } } Code For Game1: using System; using System.Collections.Generic; using System.Linq; using Microsoft.Xna.Framework; using Microsoft.Xna.Framework.Audio; using Microsoft.Xna.Framework.Content; using Microsoft.Xna.Framework.GamerServices; using Microsoft.Xna.Framework.Graphics; using Microsoft.Xna.Framework.Input; using Microsoft.Xna.Framework.Media; namespace _3D_Asteroids { /// <summary> /// This is the main type for your game /// </summary> public class Game1 : Microsoft.Xna.Framework.Game { GraphicsDeviceManager graphics; int score = 0, lives = 5; SpriteBatch spriteBatch; GameState gstate = GameState.OnMenuScreen; Menu menu = new Menu(Color.Yellow, Color.White); SpriteFont font; Texture2D background; ModelRenderer ship; Model b, a; List<ModelRenderer> bullets = new List<ModelRenderer>(); List<ModelRenderer> asteriods = new List<ModelRenderer>(); float time = 0.0f; int framecount = 0; SoundEffect effect; public Game1() { graphics = new GraphicsDeviceManager(this); graphics.PreferredBackBufferWidth = 1280; graphics.PreferredBackBufferHeight = 796; graphics.ApplyChanges(); Content.RootDirectory = "Content"; } /// <summary> /// Allows the game to perform any initialization it needs to before starting to run. /// This is where it can query for any required services and load any non-graphic /// related content. Calling base.Initialize will enumerate through any components /// and initialize them as well. /// </summary> protected override void Initialize() { // TODO: Add your initialization logic here base.Initialize(); } /// <summary> /// LoadContent will be called once per game and is the place to load /// all of your content. /// </summary> protected override void LoadContent() { // Create a new SpriteBatch, which can be used to draw textures. spriteBatch = new SpriteBatch(GraphicsDevice); font = Content.Load<SpriteFont>("Fonts\\Lucida Console"); background = Content.Load<Texture2D>("Textures\\B1_stars"); Model p1 = Content.Load<Model>("Models\\p1_wedge"); b = Content.Load<Model>("Models\\pea_proj"); a = Content.Load<Model>("Models\\asteroid1"); effect = Content.Load<SoundEffect>("Audio\\tx0_fire1"); ship = new ModelRenderer(p1, GraphicsDevice.Viewport.AspectRatio, new Vector3(0, 0, 0), new Vector3(0, 0, 9000)); } /// <summary> /// UnloadContent will be called once per game and is the place to unload /// all content. /// </summary> protected override void UnloadContent() { } /// <summary> /// Allows the game to run logic such as updating the world, /// checking for collisions, gathering input, and playing audio. /// </summary> /// <param name="gameTime">Provides a snapshot of timing values.</param> protected override void Update(GameTime gameTime) { KeyboardState state = Keyboard.GetState(PlayerIndex.One); switch (gstate) { case GameState.OnMenuScreen: { if (state.IsKeyDown(Keys.Enter)) { switch (menu.SelectedChoice) { case MenuChoices.Play: { gstate = GameState.GameStarted; break; } case MenuChoices.Exit: { this.Exit(); break; } } } if (state.IsKeyDown(Keys.Down)) { menu.MoveSelectedMenuChoiceDown(gameTime); } else if(state.IsKeyDown(Keys.Up)) { menu.MoveSelectedMenuChoiceUp(gameTime); } else { menu.KeysReleased(); } break; } case GameState.GameStarted: { foreach (ModelRenderer bullet in bullets) { if (bullet.ModelPosition.X < (ship.ModelPosition.X + 4000) && bullet.ModelPosition.Z < (ship.ModelPosition.X + 4000) && bullet.ModelPosition.X > (ship.ModelPosition.Z - 4000) && bullet.ModelPosition.Z > (ship.ModelPosition.Z - 4000)) { bullet.ModelPosition += (bullet.RotationY.Forward * 120); } else if (collidedwithasteriod(bullet)) { bullet.Kill(); } else { bullet.Kill(); } } foreach (ModelRenderer asteroid in asteriods) { if (ship.SphereBounds.Intersects(asteroid.BoxBounds)) { lives -= 1; asteroid.Kill(); // This always hits no matter where the ship goes. } else { asteroid.ModelPosition -= (asteroid.RotationY.Forward * 50); } } for (int index = 0; index < asteriods.Count; index++) { if (asteriods[index].IsAlive == false) { asteriods.RemoveAt(index); } } for (int index = 0; index < bullets.Count; index++) { if (bullets[index].IsAlive == false) { bullets.RemoveAt(index); } } if (state.IsKeyDown(Keys.Left)) { ship.RotateY(0.1f); if (state.IsKeyDown(Keys.Space)) { if (time < 17) { firebullet(); //effect.Play(); } } else { time = 0; } } else if (state.IsKeyDown(Keys.Right)) { ship.RotateY(-0.1f); if (state.IsKeyDown(Keys.Space)) { if (time < 17) { firebullet(); //effect.Play(); } } else { time = 0; } } else if (state.IsKeyDown(Keys.Up)) { ship.ModelPosition += (ship.RotationY.Forward * 50); if (state.IsKeyDown(Keys.Space)) { if (time < 17) { firebullet(); //effect.Play(); } } else { time = 0; } } else if (state.IsKeyDown(Keys.Space)) { time += gameTime.ElapsedGameTime.Milliseconds; if (time < 17) { firebullet(); //effect.Play(); } } else { time = 0.0f; } if ((framecount % 60) == 0) { createasteroid(); framecount = 0; } framecount++; break; } } base.Update(gameTime); } void firebullet() { if (bullets.Count < 3) { ModelRenderer bullet = new ModelRenderer(b, GraphicsDevice.Viewport.AspectRatio, ship.ModelPosition, new Vector3(0, 0, 9000)); bullet.RotationY = ship.RotationY; bullets.Add(bullet); } } void createasteroid() { if (asteriods.Count < 2) { Random random = new Random(); float z = random.Next(-13000, -11000); float x = random.Next(-9000, -8000); Random random2 = new Random(); int degrees = random.Next(0, 45); float radians = MathHelper.ToRadians(degrees); ModelRenderer asteroid = new ModelRenderer(a, GraphicsDevice.Viewport.AspectRatio, new Vector3(x, 0, z), new Vector3(0,0, 9000)); asteroid.RotateY(radians); asteriods.Add(asteroid); } } /// <summary> /// This is called when the game should draw itself. /// </summary> /// <param name="gameTime">Provides a snapshot of timing values.</param> protected override void Draw(GameTime gameTime) { GraphicsDevice.Clear(Color.CornflowerBlue); switch (gstate) { case GameState.OnMenuScreen: { spriteBatch.Begin(); spriteBatch.Draw(background, Vector2.Zero, Color.White); menu.DrawMenu(ref spriteBatch, font, new Vector2(GraphicsDevice.Viewport.Width / 2, GraphicsDevice.Viewport.Height / 2) - new Vector2(50f), 100f); spriteBatch.End(); break; } case GameState.GameStarted: { spriteBatch.Begin(); spriteBatch.Draw(background, Vector2.Zero, Color.White); spriteBatch.DrawString(font, "Score: " + score.ToString() + "\nLives: " + lives.ToString(), Vector2.Zero, Color.White); spriteBatch.End(); ship.Draw(); foreach (ModelRenderer bullet in bullets) { bullet.Draw(); } foreach (ModelRenderer asteroid in asteriods) { asteroid.Draw(0.1f); } break; } } base.Draw(gameTime); } bool collidedwithasteriod(ModelRenderer bullet) { foreach (ModelRenderer asteroid in asteriods) { if (bullet.SphereBounds.Intersects(asteroid.BoxBounds)) { score += 10; asteroid.Kill(); return true; } } return false; } } } }

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  • Pain Comes Instantly

    - by user701213
    When I look back at recent blog entries – many of which are not all that current (more on where my available writing time is going later) – I am struck by how many of them focus on public policy or legislative issues instead of, say, the latest nefarious cyberattack or exploit (or everyone’s favorite new pastime: coining terms for the Coming Cyberpocalypse: “digital Pearl Harbor” is so 1941). Speaking of which, I personally hope evil hackers from Malefactoria will someday hack into my bathroom scale – which in a future time will be connected to the Internet because, gosh, wouldn’t it be great to have absolutely everything in your life Internet-enabled? – and recalibrate it so I’m 10 pounds thinner. The horror. In part, my focus on public policy is due to an admitted limitation of my skill set. I enjoy reading technical articles about exploits and cybersecurity trends, but writing a blog entry on those topics would take more research than I have time for and, quite honestly, doesn’t play to my strengths. The first rule of writing is “write what you know.” The bigger contributing factor to my recent paucity of blog entries is that more and more of my waking hours are spent engaging in “thrust and parry” activity involving emerging regulations of some sort or other. I’ve opined in earlier blogs about what constitutes good and reasonable public policy so nobody can accuse me of being reflexively anti-regulation. That said, you have so many cycles in the day, and most of us would rather spend it slaying actual dragons than participating in focus groups on whether dragons are really a problem, whether lassoing them (with organic, sustainable and recyclable lassos) is preferable to slaying them – after all, dragons are people, too - and whether we need lasso compliance auditors to make sure lassos are being used correctly and humanely. (A point that seems to evade many rule makers: slaying dragons actually accomplishes something, whereas talking about “approved dragon slaying procedures and requirements” wastes the time of those who are competent to dispatch actual dragons and who were doing so very well without the input of “dragon-slaying theorists.”) Unfortunately for so many of us who would just get on with doing our day jobs, cybersecurity is rapidly devolving into the “focus groups on dragon dispatching” realm, which actual dragons slayers have little choice but to participate in. The general trend in cybersecurity is that powers-that-be – which encompasses groups other than just legislators – are often increasingly concerned and therefore feel they need to Do Something About Cybersecurity. Many seem to believe that if only we had the right amount of regulation and oversight, there would be no data breaches: a breach simply must mean Someone Is At Fault and Needs Supervision. (Leaving aside the fact that we have lots of home invasions despite a) guard dogs b) liberal carry permits c) alarm systems d) etc.) Also note that many well-managed and security-aware organizations, like the US Department of Defense, still get hacked. More specifically, many powers-that-be feel they must direct industry in a multiplicity of ways, up to and including how we actually build and deploy information technology systems. The more prescriptive the requirement, the more regulators or overseers a) can be seen to be doing something b) feel as if they are doing something regardless of whether they are actually doing something useful or cost effective. Note: an unfortunate concomitant of Doing Something is that often the cure is worse than the ailment. That is, doing what overseers want creates unfortunate byproducts that they either didn’t foresee or worse, don’t care about. After all, the logic goes, we Did Something. Prescriptive practice in the IT industry is problematic for a number of reasons. For a start, prescriptive guidance is really only appropriate if: • It is cost effective• It is “current” (meaning, the guidance doesn’t require the use of the technical equivalent of buggy whips long after horse-drawn transportation has become passé)*• It is practical (that is, pragmatic, proven and effective in the real world, not theoretical and unproven)• It solves the right problem With the above in mind, heading up the list of “you must be joking” regulations are recent disturbing developments in the Payment Card Industry (PCI) world. I’d like to give PCI kahunas the benefit of the doubt about their intentions, except that efforts by Oracle among others to make them aware of “unfortunate side effects of your requirements” – which is as tactful I can be for reasons that I believe will become obvious below - have gone, to-date, unanswered and more importantly, unchanged. A little background on PCI before I get too wound up. In 2008, the Payment Card Industry (PCI) Security Standards Council (SSC) introduced the Payment Application Data Security Standard (PA-DSS). That standard requires vendors of payment applications to ensure that their products implement specific requirements and undergo security assessment procedures. In order to have an application listed as a Validated Payment Application (VPA) and available for use by merchants, software vendors are required to execute the PCI Payment Application Vendor Release Agreement (VRA). (Are you still with me through all the acronyms?) Beginning in August 2010, the VRA imposed new obligations on vendors that are extraordinary and extraordinarily bad, short-sighted and unworkable. Specifically, PCI requires vendors to disclose (dare we say “tell all?”) to PCI any known security vulnerabilities and associated security breaches involving VPAs. ASAP. Think about the impact of that. PCI is asking a vendor to disclose to them: • Specific details of security vulnerabilities • Including exploit information or technical details of the vulnerability • Whether or not there is any mitigation available (as in a patch) PCI, in turn, has the right to blab about any and all of the above – specifically, to distribute all the gory details of what is disclosed - to the PCI SSC, qualified security assessors (QSAs), and any affiliate or agent or adviser of those entities, who are in turn permitted to share it with their respective affiliates, agents, employees, contractors, merchants, processors, service providers and other business partners. This assorted crew can’t be more than, oh, hundreds of thousands of entities. Does anybody believe that several hundred thousand people can keep a secret? Or that several hundred thousand people are all equally trustworthy? Or that not one of the people getting all that information would blab vulnerability details to a bad guy, even by accident? Or be a bad guy who uses the information to break into systems? (Wait, was that the Easter Bunny that just hopped by? Bringing world peace, no doubt.) Sarcasm aside, common sense tells us that telling lots of people a secret is guaranteed to “unsecret” the secret. Notably, being provided details of a vulnerability (without a patch) is of little or no use to companies running the affected application. Few users have the technological sophistication to create a workaround, and even if they do, most workarounds break some other functionality in the application or surrounding environment. Also, given the differences among corporate implementations of any application, it is highly unlikely that a single workaround is going to work for all corporate users. So until a patch is developed by the vendor, users remain at risk of exploit: even more so if the details of vulnerability have been widely shared. Sharing that information widely before a patch is available therefore does not help users, and instead helps only those wanting to exploit known security bugs. There’s a shocker for you. Furthermore, we already know that insider information about security vulnerabilities inevitably leaks, which is why most vendors closely hold such information and limit dissemination until a patch is available (and frequently limit dissemination of technical details even with the release of a patch). That’s the industry norm, not that PCI seems to realize or acknowledge that. Why would anybody release a bunch of highly technical exploit information to a cast of thousands, whose only “vetting” is that they are members of a PCI consortium? Oracle has had personal experience with this problem, which is one reason why information on security vulnerabilities at Oracle is “need to know” (we use our own row level access control to limit access to security bugs in our bug database, and thus less than 1% of development has access to this information), and we don’t provide some customers with more information than others or with vulnerability information and/or patches earlier than others. Failure to remember “insider information always leaks” creates problems in the general case, and has created problems for us specifically. A number of years ago, one of the UK intelligence agencies had information about a non-public security vulnerability in an Oracle product that they circulated among other UK and Commonwealth defense and intelligence entities. Nobody, it should be pointed out, bothered to report the problem to Oracle, even though only Oracle could produce a patch. The vulnerability was finally reported to Oracle by (drum roll) a US-based commercial company, to whom the information had leaked. (Note: every time I tell this story, the MI-whatever agency that created the problem gets a bit shirty with us. I know they meant well and have improved their vulnerability handling/sharing processes but, dudes, next time you find an Oracle vulnerability, try reporting it to us first before blabbing to lots of people who can’t actually fix the problem. Thank you!) Getting back to PCI: clearly, these new disclosure obligations increase the risk of exploitation of a vulnerability in a VPA and thus, of misappropriation of payment card data and customer information that a VPA processes, stores or transmits. It stands to reason that VRA’s current requirement for the widespread distribution of security vulnerability exploit details -- at any time, but particularly before a vendor can issue a patch or a workaround -- is very poor public policy. It effectively publicizes information of great value to potential attackers while not providing compensating benefits - actually, any benefits - to payment card merchants or consumers. In fact, it magnifies the risk to payment card merchants and consumers. The risk is most prominent in the time before a patch has been released, since customers often have little option but to continue using an application or system despite the risks. However, the risk is not limited to the time before a patch is issued: customers often need days, or weeks, to apply patches to systems, based upon the complexity of the issue and dependence on surrounding programs. Rather than decreasing the available window of exploit, this requirement increases the available window of exploit, both as to time available to exploit a vulnerability and the ease with which it can be exploited. Also, why would hackers focus on finding new vulnerabilities to exploit if they can get “EZHack” handed to them in such a manner: a) a vulnerability b) in a payment application c) with exploit code: the “Hacking Trifecta!“ It’s fair to say that this is probably the exact opposite of what PCI – or any of us – would want. Established industry practice concerning vulnerability handling avoids the risks created by the VRA’s vulnerability disclosure requirements. Specifically, the norm is not to release information about a security bug until the associated patch (or a pretty darn good workaround) has been issued. Once a patch is available, the notice to the user community is a high-level communication discussing the product at issue, the level of risk associated with the vulnerability, and how to apply the patch. The notices do not include either the specific customers affected by the vulnerability or forensic reports with maps of the exploit (both of which are required by the current VRA). In this way, customers have the tools they need to prioritize patching and to help prevent an attack, and the information released does not increase the risk of exploit. Furthermore, many vendors already use industry standards for vulnerability description: Common Vulnerability Enumeration (CVE) and Common Vulnerability Scoring System (CVSS). CVE helps ensure that customers know which particular issues a patch addresses and CVSS helps customers determine how severe a vulnerability is on a relative scale. Industry already provides the tools customers need to know what the patch contains and how bad the problem is that the patch remediates. So, what’s a poor vendor to do? Oracle is reaching out to other vendors subject to PCI and attempting to enlist then in a broad effort to engage PCI in rethinking (that is, eradicating) these requirements. I would therefore urge all who care about this issue, but especially those in the vendor community whose applications are subject to PCI and who may not have know they were being asked to tell-all to PCI and put their customers at risk, to do one of the following: • Contact PCI with your concerns• Contact Oracle (we are looking for vendors to sign our statement of concern)• And make sure you tell your customers that you have to rat them out to PCI if there is a breach involving the payment application I like to be charitable and say “PCI meant well” but in as important a public policy issue as what you disclose about vulnerabilities, to whom and when, meaning well isn’t enough. We need to do well. PCI, as regards this particular issue, has not done well, and has compounded the error by thus far being nonresponsive to those of us who have labored mightily to try to explain why they might want to rethink telling the entire planet about security problems with no solutions. By Way of Explanation… Non-related to PCI whatsoever, and the explanation for why I have not been blogging a lot recently, I have been working on Other Writing Venues with my sister Diane (who has also worked in the tech sector, inflicting upgrades on unsuspecting and largely ungrateful end users). I am pleased to note that we have recently (self-)published the first in the Miss Information Technology Murder Mystery series, Outsourcing Murder. The genre might best be described as “chick lit meets geek scene.” Our sisterly nom de plume is Maddi Davidson and (shameless plug follows): you can order the paper version of the book on Amazon, or the Kindle or Nook versions on www.amazon.com or www.bn.com, respectively. From our book jacket: Emma Jones, a 20-something IT consultant, is working on an outsourcing project at Tahiti Tacos, a restaurant chain offering Polynexican cuisine: refried poi, anyone? Emma despises her boss Padmanabh, a brilliant but arrogant partner in GD Consulting. When Emma discovers His-Royal-Padness’s body (verdict: death by cricket bat), she becomes a suspect.With her overprotective family and her best friend Stacey providing endless support and advice, Emma stumbles her way through an investigation of Padmanabh’s murder, bolstered by fusion food feeding frenzies, endless cups of frou-frou coffee and serious surfing sessions. While Stacey knows a PI who owes her a favor, landlady Magda urges Emma to tart up her underwear drawer before the next cute cop with a search warrant arrives. Emma’s mother offers to fix her up with a PhD student at Berkeley and showers her with self-defense gizmos while her old lover Keoni beckons from Hawai’i. And everyone, even Shaun the barista, knows a good lawyer. Book 2, Denial of Service, is coming out this summer. * Given the rate of change in technology, today’s “thou shalts” are easily next year’s “buggy whip guidance.”

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  • Clean Code Developer & Certification in IT - MSCC 21.09.2013

    It was a very busy weekend this time, and quite some hectic to organise the second meetup on a Saturday for the Mauritius Software Craftsmanship Community (MSCC) but it was absolutely fun. Following, I'm writing a brief summary about the topics we spoke about and the new impulses I got. "What a meetup... I was positively impressed. At the beginning I thought that noone would actually show up but then by the time the room got filled. Lots of conversation, great dialogues and fantastic networking between fresh students, experienced students, experienced employees, and self-employed attendees. That's what community is all about!" Above quote was my first reaction shortly after the gathering. And despite being busy during the weekend and yesterday, I took my time to reflect a little bit on things happened and statements made before writing it here on my blog. Additionally, I was also very curious about possible reactions and blogs from other attendees. Reactions from other craftsmen Let me quickly give you some links and quotes from others first... "Like Jochen posted on facebook, that was indeed a 5+ hours marathon (maybe 4 hours for me but still) … Wohoo! We’re indeed a bunch of crazy geeks who did not realise how time flew as we dived into the myriad discussions that sprouted. Yet in the end everyone was happy (:" -- Ish on MSCC meetup - The marathon (: "And the 4hours spent @ Talking drums bore its fruit..I was doing something I never did before....reading the borrowed book while walking....and though I was not that familiar with things mentionned in the book...I was skimming,scanning & flipping...reading titles...short paragraphs...and I skipped pages till I reached home." -- Yannick on Mauritius Software Craftsmanship 1st Meet-up "Hi Developers, Just wanted to share with you the meetups i attended last Saturday - [...] - The second meetup is the one hosted by Jochen Kirstätter, the MSCC, where the attendees were Craftsman, no woman, this time - all sharing the same passion of being a developer - even though it is on different platforms(Windows - Windows Phone - Linux - Adobe(yes a designer) - .Net) - but we manage to sit at the same table - sharing developer views and experience in the corporate world - also talking about good practice when coding( where Jochen initiated a discussion on Clean Coding ) i could not stay till the end - but from what i have heard - the longer you stay the more fun you have till 1600. Developers in the Facebook grouping i invite you to stay tuned about the various developer communities popping up - where you can come to share and learn good practices, develop the entrepreneurial spirit, and learn and share your passion about technologies" -- Arnaud on Facebook More feedback has been posted on the event directly. So, should I really write more? Wouldn't that spoil the impressions? Starting the day with a surprise Indeed, I was very pleased to stumble over the existence of Mobile Monday Mauritius on LinkedIn, an association about any kind of mobile app development, mobile gadgets and latest smartphones on the market. Despite the Monday in their name they had scheduled their recent meeting on Saturday between 10:00 and 12:00hrs. Wow, what a coincidence! Let's grap the bull by its horns and pay them an introductory visit. As they chose the Ebene Accelerator at the Orange Tower in Ebene it was a no-brainer to leave home a bit earlier and stop by. It was quite an experience and fun to talk to the geeks over there. Really looking forward to organise something together.... Arriving at the venue As the children got a bit uneasy at the MoMo gathering and I didn't want to disturb them too much, we arrived early at Bagatelle. Well, no problems as we went for a decent breakfast at Food Lover's Market. Shortly afterwards we went to our venue location, Talking Drums, and prepared the room for the meeting. We only had to take off a repro-painting of the wall in order to have a decent area for the projector. All went very smooth and my two little ones were of great help. Just in time, our first craftsman Avinash arrived on the spot. And then the waiting started... Luckily, not too long. Bit by bit more and more IT people came to join our meeting. Meanwhile, I used the time to give a brief introduction about the MSCC in general, what we are (hm, maybe I am) trying to achieve and that the recent phase is completely focused on creating more awareness that a community like the MSCC is active here in Mauritius. As soon as we reached some 'critical mass' of about ten people I asked everyone for a short introduction and bio, just in case... Conversation between participants started to kick in and we were actually more networking than having a focus on our topics of the day. Quick updates on latest news and development around the MSCC Finally, Clean Code Developer No matter how the position is actually called, whether it is Software Engineer, Software Developer, Programmer, Architect, or Craftsman, anyone working in IT is facing almost the same obstacles. As for the process of writing software applications there are re-occurring patterns and principles combined with some common exercise and best practices on how to resolve them. Initiated by the must-read book 'Clean Code' by Robert C. Martin (aka Uncle Bob) the concept of the Clean Code Developer (CCD) was born already some years ago. CCD is much likely to traditional martial arts where you create awareness of certain principles and learn how to apply practices to improve your style. The CCD initiative recommends to indicate your level of knowledge and experience with coloured wrist bands - equivalent to the belt colours - for various reasons. Frankly speaking, I think that the biggest advantage here is provided by the obvious recognition of conceptual understanding. For example, take the situation of a team meeting... A member with a higher grade in CCD, say Green grade, sees that there are mainly Red grades to talk to, and adjusts her way of communication to their level of understanding. The choice of words might change as certain elements of CCD are not yet familiar to all team members. So instead of talking in an abstract way which only Green grades could follow the whole scenario comes down to Red grade level. Different story, better results... Similar to learning martial arts, we only covered two grades during this occasion - black and red. Most interestingly, there was quite some positive feedback and lots of questions about the principles and practices of the red grade. And we gathered real-world examples from various craftsman and discussed them. Following the Clean Code Developer Red Grade and some annotations from our meetup: CCD Red Grade - Principles Don't Repeat Yourself - DRY Keep It Simple, Stupid (and Short) - KISS Beware of Optimisations! Favour Composition over Inheritance - FCoI Interestingly most of the attendees already heard about those key words but couldn't really classify or categorize them. It's very similar to a situation in which you do not the particular for a thing and have to describe it to others... until someone tells you the actual name and suddenly all is very simple. CCD Red Grade - Practices Follow the Boy Scouts Rule Root Cause Analysis - RCA Use a Version Control System Apply Simple Refactoring Pattern Reflect Daily Introduction to the principles and practices of Clean Code Developer - here: Red Grade As for the various ToDo's we commonly agreed that the Boy Scout Rule clearly is not limited to software development or IT administration but applies to daily life in general. Same for the root cause analysis, btw. We really had good stories with surprisingly endings and conclusions. A quick check about who is using a version control system brought more drive into the conversation. Not only that we had people that aren't using any VCS at all, we also had the 'classic' approach of backup folders and naming conventions as well as the VCS 'junkie' that has to use multiple systems at a time. Just for the records: Git and GitHub seem to be in favour of some of the attendees. Regarding the daily reflection at the end of the day we came up with an easy solution: Wrap it up as a blog entry! Certifications in IT This is kind of a controversy in IT in general. Is it interesting to go for certifications or are they completely obsolete? What are the possibilities to get certified? What are the options we have in Mauritius? How would certificates stand compared to other educational tracks like Computer Science or Web Design. The ratio between craftsmen with certifications like MCP, MSTS, CCNA or LPI versus the ones without wasn't in favour for the first group but there was a high interest in the topic itself and some were really surprised to hear that exam preparations are completely free available online including temporarily voucher codes for either discounts or completely free exams. Furthermore, we discussed possible options on forming so-called study groups on a specific certificates and organising more frequent meetups in order to learn together. Taking into consideration that we have sponsored access to the video course material of Pluralsight (and now PeepCode as well as TrainSignal), we might give it a try by the end of the year. Current favourites are LPIC Level 1 and one of the Microsoft exams 40-78x. Feedback and ideas for the MSCC The closing conversations and discussions about how the MSCC is recently doing, what are the possibilities and what's (hopefully) going to happen in the future were really fertile and I made a couple of mental bullet points which I'm looking forward to tackle down together with orher craftsmen. Eventually, it might be a good option to elaborate on some issues during our weekly Code & Coffee sessions one Wednesday morning. Active discussion on various IT topics like certifications (LPI, MCP, CCNA, etc) and sharing experience Finally, we made it till the end of the planned time. Well, actually the talk was still on and we continued even after 16:00hrs. Unfortunately, we (the children and I) had to leave for evening activities. My resume of the day... It was great to have 15 craftsmen in one room. There are hundreds of IT geeks out there in Mauritius, and as Mauritius Software Craftsmanship Community we still have a lot of work to do to pass on the message to some more key players and companies. Currently, it seems that we are able to attract a good number of students in Computer Science... but we have a lot more to offer, even or especially for IT people on the job. I'm already looking forward to our next Saturday meetup in the near future. PS: Meetup pictures are courtesy of Nirvan Pagooah. Thanks for sharing...

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  • Code Reuse is (Damn) Hard

    - by James Michael Hare
    Being a development team lead, the task of interviewing new candidates was part of my job.  Like any typical interview, we started with some easy questions to get them warmed up and help calm their nerves before hitting the hard stuff. One of those easier questions was almost always: “Name some benefits of object-oriented development.”  Nearly every time, the candidate would chime in with a plethora of canned answers which typically included: “it helps ease code reuse.”  Of course, this is a gross oversimplification.  Tools only ease reuse, its developers that ultimately can cause code to be reusable or not, regardless of the language or methodology. But it did get me thinking…  we always used to say that as part of our mantra as to why Object-Oriented Programming was so great.  With polymorphism, inheritance, encapsulation, etc. we in essence set up the concepts to help facilitate reuse as much as possible.  And yes, as a developer now of many years, I unquestionably held that belief for ages before it really struck me how my views on reuse have jaded over the years.  In fact, in many ways Agile rightly eschews reuse as taking a backseat to developing what's needed for the here and now.  It used to be I was in complete opposition to that view, but more and more I've come to see the logic in it.  Too many times I've seen developers (myself included) get lost in design paralysis trying to come up with the perfect abstraction that would stand all time.  Nearly without fail, all of these pieces of code become obsolete in a matter of months or years. It’s not that I don’t like reuse – it’s just that reuse is hard.  In fact, reuse is DAMN hard.  Many times it is just a distraction that eats up architect and developer time, and worse yet can be counter-productive and force wrong decisions.  Now don’t get me wrong, I love the idea of reusable code when it makes sense.  These are in the few cases where you are designing something that is inherently reusable.  The problem is, most business-class code is inherently unfit for reuse! Furthermore, the code that is reusable will often fail to be reused if you don’t have the proper framework in place for effective reuse that includes standardized versioning, building, releasing, and documenting the components.  That should always be standard across the board when promoting reusable code.  All of this is hard, and it should only be done when you have code that is truly reusable or you will be exerting a large amount of development effort for very little bang for your buck. But my goal here is not to get into how to reuse (that is a topic unto itself) but what should be reused.  First, let’s look at an extension method.  There’s many times where I want to kick off a thread to handle a task, then when I want to reign that thread in of course I want to do a Join on it.  But what if I only want to wait a limited amount of time and then Abort?  Well, I could of course write that logic out by hand each time, but it seemed like a great extension method: 1: public static class ThreadExtensions 2: { 3: public static bool JoinOrAbort(this Thread thread, TimeSpan timeToWait) 4: { 5: bool isJoined = false; 6:  7: if (thread != null) 8: { 9: isJoined = thread.Join(timeToWait); 10:  11: if (!isJoined) 12: { 13: thread.Abort(); 14: } 15: } 16: return isJoined; 17: } 18: } 19:  When I look at this code, I can immediately see things that jump out at me as reasons why this code is very reusable.  Some of them are standard OO principles, and some are kind-of home grown litmus tests: Single Responsibility Principle (SRP) – The only reason this extension method need change is if the Thread class itself changes (one responsibility). Stable Dependencies Principle (SDP) – This method only depends on classes that are more stable than it is (System.Threading.Thread), and in itself is very stable, hence other classes may safely depend on it. It is also not dependent on any business domain, and thus isn't subject to changes as the business itself changes. Open-Closed Principle (OCP) – This class is inherently closed to change. Small and Stable Problem Domain – This method only cares about System.Threading.Thread. All-or-None Usage – A user of a reusable class should want the functionality of that class, not parts of that functionality.  That’s not to say they most use every method, but they shouldn’t be using a method just to get half of its result. Cost of Reuse vs. Cost to Recreate – since this class is highly stable and minimally complex, we can offer it up for reuse very cheaply by promoting it as “ready-to-go” and already unit tested (important!) and available through a standard release cycle (very important!). Okay, all seems good there, now lets look at an entity and DAO.  I don’t know about you all, but there have been times I’ve been in organizations that get the grand idea that all DAOs and entities should be standardized and shared.  While this may work for small or static organizations, it’s near ludicrous for anything large or volatile. 1: namespace Shared.Entities 2: { 3: public class Account 4: { 5: public int Id { get; set; } 6:  7: public string Name { get; set; } 8:  9: public Address HomeAddress { get; set; } 10:  11: public int Age { get; set;} 12:  13: public DateTime LastUsed { get; set; } 14:  15: // etc, etc, etc... 16: } 17: } 18:  19: ... 20:  21: namespace Shared.DataAccess 22: { 23: public class AccountDao 24: { 25: public Account FindAccount(int id) 26: { 27: // dao logic to query and return account 28: } 29:  30: ... 31:  32: } 33: } Now to be fair, I’m not saying there doesn’t exist an organization where some entites may be extremely static and unchanging.  But at best such entities and DAOs will be problematic cases of reuse.  Let’s examine those same tests: Single Responsibility Principle (SRP) – The reasons to change for these classes will be strongly dependent on what the definition of the account is which can change over time and may have multiple influences depending on the number of systems an account can cover. Stable Dependencies Principle (SDP) – This method depends on the data model beneath itself which also is largely dependent on the business definition of an account which can be very inherently unstable. Open-Closed Principle (OCP) – This class is not really closed for modification.  Every time the account definition may change, you’d need to modify this class. Small and Stable Problem Domain – The definition of an account is inherently unstable and in fact may be very large.  What if you are designing a system that aggregates account information from several sources? All-or-None Usage – What if your view of the account encompasses data from 3 different sources but you only care about one of those sources or one piece of data?  Should you have to take the hit of looking up all the other data?  On the other hand, should you have ten different methods returning portions of data in chunks people tend to ask for?  Neither is really a great solution. Cost of Reuse vs. Cost to Recreate – DAOs are really trivial to rewrite, and unless your definition of an account is EXTREMELY stable, the cost to promote, support, and release a reusable account entity and DAO are usually far higher than the cost to recreate as needed. It’s no accident that my case for reuse was a utility class and my case for non-reuse was an entity/DAO.  In general, the smaller and more stable an abstraction is, the higher its level of reuse.  When I became the lead of the Shared Components Committee at my workplace, one of the original goals we looked at satisfying was to find (or create), version, release, and promote a shared library of common utility classes, frameworks, and data access objects.  Now, of course, many of you will point to nHibernate and Entity for the latter, but we were looking at larger, macro collections of data that span multiple data sources of varying types (databases, web services, etc). As we got deeper and deeper in the details of how to manage and release these items, it quickly became apparent that while the case for reuse was typically a slam dunk for utilities and frameworks, the data access objects just didn’t “smell” right.  We ended up having session after session of design meetings to try and find the right way to share these data access components. When someone asked me why it was taking so long to iron out the shared entities, my response was quite simple, “Reuse is hard...”  And that’s when I realized, that while reuse is an awesome goal and we should strive to make code maintainable, often times you end up creating far more work for yourself than necessary by trying to force code to be reusable that inherently isn’t. Think about classes the times you’ve worked in a company where in the design session people fight over the best way to implement a class to make it maximally reusable, extensible, and any other buzzwordable.  Then think about how quickly that design became obsolete.  Many times I set out to do a project and think, “yes, this is the best design, I can extend it easily!” only to find out the business requirements change COMPLETELY in such a way that the design is rendered invalid.  Code, in general, tends to rust and age over time.  As such, writing reusable code can often be difficult and many times ends up being a futile exercise and worse yet, sometimes makes the code harder to maintain because it obfuscates the design in the name of extensibility or reusability. So what do I think are reusable components? Generic Utility classes – these tend to be small classes that assist in a task and have no business context whatsoever. Implementation Abstraction Frameworks – home-grown frameworks that try to isolate changes to third party products you may be depending on (like writing a messaging abstraction layer for publishing/subscribing that is independent of whether you use JMS, MSMQ, etc). Simplification and Uniformity Frameworks – To some extent this is similar to an abstraction framework, but there may be one chosen provider but a development shop mandate to perform certain complex items in a certain way.  Or, perhaps to simplify and dumb-down a complex task for the average developer (such as implementing a particular development-shop’s method of encryption). And what are less reusable? Application and Business Layers – tend to fluctuate a lot as requirements change and new features are added, so tend to be an unstable dependency.  May be reused across applications but also very volatile. Entities and Data Access Layers – these tend to be tuned to the scope of the application, so reusing them can be hard unless the abstract is very stable. So what’s the big lesson?  Reuse is hard.  In fact it’s damn hard.  And much of the time I’m not convinced we should focus too hard on it. If you’re designing a utility or framework, then by all means design it for reuse.  But you most also really set down a good versioning, release, and documentation process to maximize your chances.  For anything else, design it to be maintainable and extendable, but don’t waste the effort on reusability for something that most likely will be obsolete in a year or two anyway.

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  • The Return Of __FILE__ And __LINE__ In .NET 4.5

    - by Alois Kraus
    Good things are hard to kill. One of the most useful predefined compiler macros in C/C++ were __FILE__ and __LINE__ which do expand to the compilation units file name and line number where this value is encountered by the compiler. After 4.5 versions of .NET we are on par with C/C++ again. It is of course not a simple compiler expandable macro it is an attribute but it does serve exactly the same purpose. Now we do get CallerLineNumberAttribute  == __LINE__ CallerFilePathAttribute        == __FILE__ CallerMemberNameAttribute  == __FUNCTION__ (MSVC Extension)   The most important one is CallerMemberNameAttribute which is very useful to implement the INotifyPropertyChanged interface without the need to hard code the name of the property anymore. Now you can simply decorate your change method with the new CallerMemberName attribute and you get the property name as string directly inserted by the C# compiler at compile time.   public string UserName { get { return _userName; } set { _userName=value; RaisePropertyChanged(); // no more RaisePropertyChanged(“UserName”)! } } protected void RaisePropertyChanged([CallerMemberName] string member = "") { var copy = PropertyChanged; if(copy != null) { copy(new PropertyChangedEventArgs(this, member)); } } Nice and handy. This was obviously the prime reason to implement this feature in the C# 5.0 compiler. You can repurpose this feature for tracing to get your hands on the method name of your caller along other stuff very fast now. All infos are added during compile time which is much faster than other approaches like walking the stack. The example on MSDN shows the usage of this attribute with an example public static void TraceMessage(string message, [CallerMemberName] string memberName = "", [CallerFilePath] string sourceFilePath = "", [CallerLineNumber] int sourceLineNumber = 0) { Console.WriteLine("Hi {0} {1} {2}({3})", message, memberName, sourceFilePath, sourceLineNumber); }   When I do think of tracing I do usually want to have a API which allows me to Trace method enter and leave Trace messages with a severity like Info, Warning, Error When I do print a trace message it is very useful to print out method and type name as well. So your API must either be able to pass the method and type name as strings or extract it automatically via walking back one Stackframe and fetch the infos from there. The first glaring deficiency is that there is no CallerTypeAttribute yet because the C# compiler team was not satisfied with its performance.   A usable Trace Api might therefore look like   enum TraceTypes { None = 0, EnterLeave = 1 << 0, Info = 1 << 1, Warn = 1 << 2, Error = 1 << 3 } class Tracer : IDisposable { string Type; string Method; public Tracer(string type, string method) { Type = type; Method = method; if (IsEnabled(TraceTypes.EnterLeave,Type, Method)) { } } private bool IsEnabled(TraceTypes traceTypes, string Type, string Method) { // Do checking here if tracing is enabled return false; } public void Info(string fmt, params object[] args) { } public void Warn(string fmt, params object[] args) { } public void Error(string fmt, params object[] args) { } public static void Info(string type, string method, string fmt, params object[] args) { } public static void Warn(string type, string method, string fmt, params object[] args) { } public static void Error(string type, string method, string fmt, params object[] args) { } public void Dispose() { // trace method leave } } This minimal trace API is very fast but hard to maintain since you need to pass in the type and method name as hard coded strings which can change from time to time. But now we have at least CallerMemberName to rid of the explicit method parameter right? Not really. Since any acceptable usable trace Api should have a method signature like Tracexxx(… string fmt, params [] object args) we not able to add additional optional parameters after the args array. If we would put it before the format string we would need to make it optional as well which would mean the compiler would need to figure out what our trace message and arguments are (not likely) or we would need to specify everything explicitly just like before . There are ways around this by providing a myriad of overloads which in the end are routed to the very same method but that is ugly. I am not sure if nobody inside MS agrees that the above API is reasonable to have or (more likely) that the whole talk about you can use this feature for diagnostic purposes was not a core feature at all but a simple byproduct of making the life of INotifyPropertyChanged implementers easier. A way around this would be to allow for variable argument arrays after the params keyword another set of optional arguments which are always filled by the compiler but I do not know if this is an easy one. The thing I am missing much more is the not provided CallerType attribute. But not in the way you would think of. In the API above I did add some filtering based on method and type to stay as fast as possible for types where tracing is not enabled at all. It should be no more expensive than an additional method call and a bool variable check if tracing for this type is enabled at all. The data is tightly bound to the calling type and method and should therefore become part of the static type instance. Since extending the CLR type system for tracing is not something I do expect to happen I have come up with an alternative approach which allows me basically to attach run time data to any existing type object in super fast way. The key to success is the usage of generics.   class Tracer<T> : IDisposable { string Method; public Tracer(string method) { if (TraceData<T>.Instance.Enabled.HasFlag(TraceTypes.EnterLeave)) { } } public void Dispose() { if (TraceData<T>.Instance.Enabled.HasFlag(TraceTypes.EnterLeave)) { } } public static void Info(string fmt, params object[] args) { } /// <summary> /// Every type gets its own instance with a fresh set of variables to describe the /// current filter status. /// </summary> /// <typeparam name="T"></typeparam> internal class TraceData<UsingType> { internal static TraceData<UsingType> Instance = new TraceData<UsingType>(); public bool IsInitialized = false; // flag if we need to reinit the trace data in case of reconfigured trace settings at runtime public TraceTypes Enabled = TraceTypes.None; // Enabled trace levels for this type } } We do not need to pass the type as string or Type object to the trace Api. Instead we define a generic Api that accepts the using type as generic parameter. Then we can create a TraceData static instance which is due to the nature of generics a fresh instance for every new type parameter. My tests on my home machine have shown that this approach is as fast as a simple bool flag check. If you have an application with many types using tracing you do not want to bring the app down by simply enabling tracing for one special rarely used type. The trace filter performance for the types which are not enabled must be therefore the fasted code path. This approach has the nice side effect that if you store the TraceData instances in one global list you can reconfigure tracing at runtime safely by simply setting the IsInitialized flag to false. A similar effect can be achieved with a global static Dictionary<Type,TraceData> object but big hash tables have random memory access semantics which is bad for cache locality and you always need to pay for the lookup which involves hash code generation, equality check and an indexed array access. The generic version is wicked fast and allows you to add more features to your tracing Api with minimal perf overhead. But it is cumbersome to write the generic type argument always explicitly and worse if you do refactor code and move parts of it to other classes it might be that you cannot configure tracing correctly. I would like therefore to decorate my type with an attribute [CallerType] class Tracer<T> : IDisposable to tell the compiler to fill in the generic type argument automatically. class Program { static void Main(string[] args) { using (var t = new Tracer()) // equivalent to new Tracer<Program>() { That would be really useful and super fast since you do not need to pass any type object around but you do have full type infos at hand. This change would be breaking if another non generic type exists in the same namespace where now the generic counterpart would be preferred. But this is an acceptable risk in my opinion since you can today already get conflicts if two generic types of the same name are defined in different namespaces. This would be only a variation of this issue. When you do think about this further you can add more features like to trace the exception in your Dispose method if the method is left with an exception with that little trick I did write some time ago. You can think of tracing as a super fast and configurable switch to write data to an output destination or to execute alternative actions. With such an infrastructure you can e.g. Reconfigure tracing at run time. Take a memory dump when a specific method is left with a specific exception. Throw an exception when a specific trace statement is hit (useful for testing error conditions). Execute a passed delegate which e.g. dumps additional state when enabled. Write data to an in memory ring buffer and dump it when specific events do occur (e.g. method is left with an exception, triggered from outside). Write data to an output device. …. This stuff is really useful to have when your code is in production on a mission critical server and you need to find the root cause of sporadic crashes of your application. It could be a buggy graphics card driver which throws access violations into your application (ok with .NET 4 not anymore except if you enable a compatibility flag) where you would like to have a minidump or you have reached after two weeks of operation a state where you need a full memory dump at a specific point in time in the middle of an transaction. At my older machine I do get with this super fast approach 50 million traces/s when tracing is disabled. When I do know that tracing is enabled for this type I can walk the stack by using StackFrameHelper.GetStackFramesInternal to check further if a specific action or output device is configured for this method which is about 2-3 times faster than the regular StackTrace class. Even with one String.Format I am down to 3 million traces/s so performance is not so important anymore since I do want to do something now. The CallerMemberName feature of the C# 5 compiler is nice but I would have preferred to get direct access to the MethodHandle and not to the stringified version of it. But I really would like to see a CallerType attribute implemented to fill in the generic type argument of the call site to augment the static CLR type data with run time data.

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  • Filtering List Data with a jQuery-searchFilter Plugin

    - by Rick Strahl
    When dealing with list based data on HTML forms, filtering that data down based on a search text expression is an extremely useful feature. We’re used to search boxes on just about anything these days and HTML forms should be no different. In this post I’ll describe how you can easily filter a list down to just the elements that match text typed into a search box. It’s a pretty simple task and it’s super easy to do, but I get a surprising number of comments from developers I work with who are surprised how easy it is to hook up this sort of behavior, that I thought it’s worth a blog post. But Angular does that out of the Box, right? These days it seems everybody is raving about Angular and the rich SPA features it provides. One of the cool features of Angular is the ability to do drop dead simple filters where you can specify a filter expression as part of a looping construct and automatically have that filter applied so that only items that match the filter show. I think Angular has single handedly elevated search filters to first rate, front-row status because it’s so easy. I love using Angular myself, but Angular is not a generic solution to problems like this. For one thing, using Angular requires you to render the list data with Angular – if you have data that is server rendered or static, then Angular doesn’t work. Not all applications are client side rendered SPAs – not by a long shot, and nor do all applications need to become SPAs. Long story short, it’s pretty easy to achieve text filtering effects using jQuery (or plain JavaScript for that matter) with just a little bit of work. Let’s take a look at an example. Why Filter? Client side filtering is a very useful tool that can make it drastically easier to sift through data displayed in client side lists. In my applications I like to display scrollable lists that contain a reasonably large amount of data, rather than the classic paging style displays which tend to be painful to use. So I often display 50 or so items per ‘page’ and it’s extremely useful to be able to filter this list down. Here’s an example in my Time Trakker application where I can quickly glance at various common views of my time entries. I can see Recent Entries, Unbilled Entries, Open Entries etc and filter those down by individual customers and so forth. Each of these lists results tends to be a few pages worth of scrollable content. The following screen shot shows a filtered view of Recent Entries that match the search keyword of CellPage: As you can see in this animated GIF, the filter is applied as you type, displaying only entries that match the text anywhere inside of the text of each of the list items. This is an immediately useful feature for just about any list display and adds significant value. A few lines of jQuery The good news is that this is trivially simple using jQuery. To get an idea what this looks like, here’s the relevant page layout showing only the search box and the list layout:<div id="divItemWrapper"> <div class="time-entry"> <div class="time-entry-right"> May 11, 2014 - 7:20pm<br /> <span style='color:steelblue'>0h:40min</span><br /> <a id="btnDeleteButton" href="#" class="hoverbutton" data-id="16825"> <img src="images/remove.gif" /> </a> </div> <div class="punchedoutimg"></div> <b><a href='/TimeTrakkerWeb/punchout/16825'>Project Housekeeping</a></b><br /> <small><i>Sawgrass</i></small> </div> ... more items here </div> So we have a searchbox txtSearchPage and a bunch of DIV elements with a .time-entry CSS class attached that makes up the list of items displayed. To hook up the search filter with jQuery is merely a matter of a few lines of jQuery code hooked to the .keyup() event handler: <script type="text/javascript"> $("#txtSearchPage").keyup(function() { var search = $(this).val(); $(".time-entry").show(); if (search) $(".time-entry").not(":contains(" + search + ")").hide(); }); </script> The idea here is pretty simple: You capture the keystroke in the search box and capture the search text. Using that search text you first make all items visible and then hide all the items that don’t match. Since DOM changes are applied after a method finishes execution in JavaScript, the show and hide operations are effectively batched up and so the view changes only to the final list rather than flashing the whole list and then removing items on a slow machine. You get the desired effect of the list showing the items in question. Case Insensitive Filtering But there is one problem with the solution above: The jQuery :contains filter is case sensitive, so your search text has to match expressions explicitly which is a bit cumbersome when typing. In the screen capture above I actually cheated – I used a custom filter that provides case insensitive contains behavior. jQuery makes it really easy to create custom query filters, and so I created one called containsNoCase. Here’s the implementation of this custom filter:$.expr[":"].containsNoCase = function(el, i, m) { var search = m[3]; if (!search) return false; return new RegExp(search, "i").test($(el).text()); }; This filter can be added anywhere where page level JavaScript runs – in page script or a seperately loaded .js file.  The filter basically extends jQuery with a : expression. Filters get passed a tokenized array that contains the expression. In this case the m[3] contains the search text from inside of the brackets. A filter basically looks at the active element that is passed in and then can return true or false to determine whether the item should be matched. Here I check a regular expression that looks for the search text in the element’s text. So the code for the filter now changes to:$(".time-entry").not(":containsNoCase(" + search + ")").hide(); And voila – you now have a case insensitive search.You can play around with another simpler example using this Plunkr:http://plnkr.co/edit/hDprZ3IlC6uzwFJtgHJh?p=preview Wrapping it up in a jQuery Plug-in To make this even easier to use and so that you can more easily remember how to use this search type filter, we can wrap this logic into a small jQuery plug-in:(function($, undefined) { $.expr[":"].containsNoCase = function(el, i, m) { var search = m[3]; if (!search) return false; return new RegExp(search, "i").test($(el).text()); }; $.fn.searchFilter = function(options) { var opt = $.extend({ // target selector targetSelector: "", // number of characters before search is applied charCount: 1 }, options); return this.each(function() { var $el = $(this); $el.keyup(function() { var search = $(this).val(); var $target = $(opt.targetSelector); $target.show(); if (search && search.length >= opt.charCount) $target.not(":containsNoCase(" + search + ")").hide(); }); }); }; })(jQuery); To use this plug-in now becomes a one liner:$("#txtSearchPagePlugin").searchFilter({ targetSelector: ".time-entry", charCount: 2}) You attach the .searchFilter() plug-in to the text box you are searching and specify a targetSelector that is to be filtered. Optionally you can specify a character count at which the filter kicks in since it’s kind of useless to filter at a single character typically. Summary This is s a very easy solution to a cool user interface feature your users will thank you for. Search filtering is a simple but highly effective user interface feature, and as you’ve seen in this post it’s very simple to create this behavior with just a few lines of jQuery code. While all the cool kids are doing Angular these days, jQuery is still useful in many applications that don’t embrace the ‘everything generated in JavaScript’ paradigm. I hope this jQuery plug-in or just the raw jQuery will be useful to some of you… Resources Example on Plunker© Rick Strahl, West Wind Technologies, 2005-2014Posted in jQuery  HTML5  JavaScript   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • When was sys.dm_os_wait_stats last cleared?

    - by SQLOS Team
    The sys.dm_os_wait_stats DMV provides essential metrics for diagnosing SQL Server performance problems. Returning incrementally accumulating information about all the completed waits encountered by executing threads it is a useful way to identify bottlenecks such as IO latency issues or waits on locks. The counters are reset each time SQL server is restarted, or when the following command is run: DBCC SQLPERF ('sys.dm_os_wait_stats', CLEAR); To make sense out of these wait values you need to know how they change over time. Suppose you are asked to troubleshoot a system and you don't know when the wait stats were last zeroed. Is there any way to find the elapsed time since this happened? If the wait stats were not cleared using the DBCC SQLPERF command then you can simply correlate the stats with the time SQL Server was started using the sqlserver_start_time column introduced in SQL Server 2008 R2: SELECT sqlserver_start_time from sys.dm_os_sys_info However how do you tell if someone has run DBCC SQLPERF ('sys.dm_os_wait_stats', CLEAR) since the server was started, and if they did, when? Without this information the initial, or historical, wait_stats have less value until you can measure deltas over time. There is a way to at least estimate when the stats were last cleared, by using the wait stats themselves and choosing a thread that spends most of its time sleeping. A good candidate is the SQL Trace incremental flush task, which mostly sleeps (in 4 second intervals) and in between it attempts to flush (if there are new events – which is rare when only default trace is running) – so it pretty much sleeps all the time. Hence the time it has spent waiting is very close to the elapsed time since the counter was reset. Credit goes to Ivan Penkov in the SQLOS dev team for suggesting this. Here's an example (excuse formatting): 144 seconds after the server was started: select top 10 wait_type, wait_time_ms from sys.dm_os_wait_stats order by wait_time_ms desc wait_type                                                               wait_time_ms--------------------------------------------------------------------------------------------------------------- XE_DISPATCHER_WAIT                                      242273LAZYWRITER_SLEEP                                          146010LOGMGR_QUEUE                                                145412DIRTY_PAGE_POLL                                             145411XE_TIMER_EVENT                                               145216REQUEST_FOR_DEADLOCK_SEARCH             145194SQLTRACE_INCREMENTAL_FLUSH_SLEEP    144325SLEEP_TASK                                                        73359BROKER_TO_FLUSH                                           73113PREEMPTIVE_OS_AUTHENTICATIONOPS       143 (10 rows affected) Reset: DBCC SQLPERF('sys.dm_os_wait_stats', CLEAR)" DBCC execution completed. If DBCC printed error messages, contact your system administrator. After 8 seconds: select top 10 wait_type, wait_time_ms from sys.dm_os_wait_stats order by wait_time_ms desc wait_type                                                                 wait_time_ms--------------------------------------------------------------------------------------------------------------------- REQUEST_FOR_DEADLOCK_SEARCH              10013LAZYWRITER_SLEEP                                           8124SQLTRACE_INCREMENTAL_FLUSH_SLEEP     8017LOGMGR_QUEUE                                                 7579DIRTY_PAGE_POLL                                              7532XE_TIMER_EVENT                                                5007BROKER_TO_FLUSH                                            4118SLEEP_TASK                                                         3089PREEMPTIVE_OS_AUTHENTICATIONOPS        28SOS_SCHEDULER_YIELD                                   27 (10 rows affected)   After 12 seconds: select top 10 wait_type, wait_time_ms from sys.dm_os_wait_stats order by wait_time_ms desc wait_type                                                                  wait_time_ms------------------------------------------------------------------------------------------------------ REQUEST_FOR_DEADLOCK_SEARCH               15020LAZYWRITER_SLEEP                                            14206LOGMGR_QUEUE                                                  14036DIRTY_PAGE_POLL                                               13973SQLTRACE_INCREMENTAL_FLUSH_SLEEP      12026XE_TIMER_EVENT                                                 10014SLEEP_TASK                                                          7207BROKER_TO_FLUSH                                             7207PREEMPTIVE_OS_AUTHENTICATIONOPS         57SOS_SCHEDULER_YIELD                                     28 (10 rows affected) It may not be accurate to the millisecond, but it can provide a useful data point, and give an indication whether the wait stats were manually cleared after startup, and if so approximately when. - Guy     Originally posted at http://blogs.msdn.com/b/sqlosteam/

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  • Segmentation. strcmp [C]

    - by FILIaS
    Hello, I have a file with format: [name][number][amount] number is taken as a string. and im using it in a strcmp. Problem is that i get a segmentation fault. I know that on most cases when strcmp signs segmentation fault it means that one of the parameters is null or cant find its "end" ('\0'). I checked with gdb and i cant say if this is the problem.Take a look: > (gdb) bt full > #0 0x08048729 in lookup (hashtable=0x804b008, hashval=27, > number=0x804b740 "6900101001") > list = 0xffffffff > #1 0x080487ac in add (hashtable=0x804b008, > number=0x804b740 "9900101001", name=0x804b730 "Smithpolow", > time=6943) > new_elem = 0xffffffff > hashval = 27 > #2 0x08048b25 in main (argc=1, argv=0xbffff4b4) > number = 0x804b740 "9900101001" > name = 0x804b730 "Smithpolow" > time = 6943 > i = 2 Code: clientsList *lookup_on_Clients(clientsHashTable *hashtable,int hashval,char number[10]) { printf("NUMBER:%s\n",number); clientsList *list=hashtable[hashval].head; for(list; list!=NULL; list=list->next){ if (strcmp(number,list->number)==0) //SEGMENTATION! return list; } return NULL; } int add ( HashTable* hashtable,char number[10],char* name,int time) { List *new_elem; int hashval=hash (hashtable,number); new_elem=hashtable[hashval].head; if(hashtable[hashval].length>0) { if ((lookup (hashtable,hashval,number))!=NULL) {return 0;} } //an den uparxei stoixeio sth lista if (!(new_elem=malloc(sizeof(struct clientsList)))){ return -1;} //insert values for the new elem new_elem->number=strdup(number); new_elem->name=strdup(name); new_elem->time=time; hashtable[hashval].head=new_elem; new_elem->next=NULL; hashtable[hashval].length++; /* rehash existing entries if necessary */ if(hashTableSize(hashtable)>= 2*primes[PrimesIndex]) { hashtable = expand(hashtable); if (hashtable ==NULL){ return 0; } PrimesIndex++; } return 1; } and the main: FILE * File2; if ( ( File2=fopen(" File.txt","r")) !=NULL ) { // File.txt format: [name number time] e.g lountemis 6900254565 700651 int li = 0; char *lin = (char *) malloc(MAX_LINE * sizeof(char)); while(fgets(lin, MAX_LINE, clientFile2) != NULL) { token = my_linetok(lin, " "); if(token != NULL) { char* number ; char* name; int time; int i; for(i = 0; token[i] != NULL; i++) { name=strdup(token[0]); number=strdup(token[1]); time=atoi(token[2]); if (i==2) { int insertDone=0; insertDone =add(my_hash_table,number,name,time); } } free(name); free(number); free(token); } else { printf("Error reading line %s\n", lin); exit(1); } } } else { printf("Error opening file \nEXIT!"); exit(0); }

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  • Faulty to use memcache together with a php web-browser-game in this way?

    - by Crowye
    Background We are currently working on a strategy web-browser game based on php, html and javascript. The plan is to have 10,000+ users playing within the same world. Currently we are using memcached to: store json static data, language files store changeable serialized php class objects (such as armies, inventorys, unit-containers, buildings, etc) In the back we have a mysql server running and holding all the game data aswell. When a object is loaded through our ObjectLoader it loads in this order: checks a static hashmap in the script for the object checks memcache if it has already been loaded into it otherwise loads from database, and saves it into memcache and the static temp hashmap We have built the whole game using a class-object-oriented approach where functionality is always made between objects. Beause of this we think we have managed to get a nice structure, and with the help of memcached we have received good request times from client-server when interacting with the game. I'm aware that memcache is not synchronized, and also is not commonly used for holding a full game in memory. In the beginning after a server's startup the load times when loading objects into memcache for the first time will be high, but after the server's been online for a while and most loads are from memcache, the loads will be well reduced. Currently we are saving changed objects into memcache and database at the same time. Earlier we had an idea to save objects into db only after a certain time or at intervals, but due to risk inconsistency if the memcache/server went down, we skipped it for now. Client requests to server often return object's status simple json-format without changing the object, which in turn is represented in the browser visually with images and javascript. But from time to time depending on when an object was last updated, it updates them with new information (e.g. a build-queue holding planned buildings time-progress is increased, and/or planned-queue-items-array has changed). Questions: Do you see how this could work or are we walking in blindness here? Do you expect us to have a lot of inconsistency issues if someone loads and updates the a memcache objects while someone else does the same? Is it even doable to do it in the way he have done it? Seems to be working fine atm, but so far we have only been 4 people online at the same time.. Is some other cache program more fit for this class-object approach than memcached? Is there any other tips you have for this situation? UPDATE Since it is simply a "normal webpage" (no applet, flash, etc), we are implementing the game so that the server is the only one holding a "real game-state".. the state of the different javascript-objects on the client is more like a approximative version of the server's game state. From time to time and before you do certain things important things, the client's visual state is updated to the server's state (e.g. the client things he can afford a barracks, asks the server to build a barracks, server updates current resources according to income-data on server and then tries to build a barracks or casts an error-message, and then sends the current server-state on resources, buildings back to the client).. It is not a fast-paced game lika real strategy game. More like a quite slow 3-4 months playtime game, where buildings can take +1 minute up to several days to complete.

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  • change value upon select

    - by Link
    what i'm aiming is to show the other div when it selects one of the two options Full time and Part Time and if possible compute a different value for each When the user selects Part time the value of PrcA will change to PrcB this is the code i used <!====================================================================================> <script language="javascript"> <!--// function dm(amount) { string = "" + amount; dec = string.length - string.indexOf('.'); if (string.indexOf('.') == -1) return string + '.00'; if (dec == 1) return string + '00'; if (dec == 2) return string + '0'; if (dec > 3) return string.substring(0,string.length-dec+3); return string; } function calculate() { QtyA = 0; TotA = 0; PrcA = 1280; PrcB = 640; if (document.form1.qtyA.value > "") { QtyA = document.form1.qtyA.value }; document.form1.qtyA.value = eval(QtyA); TotA = QtyA * PrcA; document.form1.totalA.value = dm(eval(TotA)); Totamt = eval(TotA) ; document.form1.GrandTotal.value = dm(eval(Totamt)); } //--> </script> <!====================================================================================> <p> <label for="acct" style="margin-right:90px;"><strong>Account Type<strong><font color=red size=3> * </font></strong></label> <select name="acct" style="background-color:white;" class="validate[custom[serv]] select-input" id="acct" value=""> <option value="Full Time">Full-Time</option> <option value="Part Time">Part-Time</option> <option selected="selected" value=""></option> </select></p> <!====================================================================================> <script> $(document).ready(function() { $("input[name$='acct']").select(function() { var test = $(this).val(); $("div.desc").hide(); $("#acct" + test).show(); }); }); </script> <!====================================================================================> <p> <table><tr><td> <lable style="margin-right:91px;"># of Agent(s)<font color=red size=3> * </font></lable> </td><td> <input style="width:25px; margin-left:5px;" type="text" class="validate[custom[agnt]] text-input" name="qtyA" id="qtyA" onchange="calculate()" /> </td><td> <div id="acctFull Time" class="desc"> x 1280 = </div> <div id="acctPart Time" class="desc" style="display:none"> x 640 = </div> </td><td> $<input style="width:80px; margin-left:5px;" type="text" readonly="readonly" name="totalA" id="totalA" onchange="calculate()" /> </p> </td></tr></table> is there any way for me to achieve this?

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  • Android ActiveSync/Outlook Error

    - by Kyle B.
    Getting the following error when attempt to press "Refresh" inside the Mail app for an exchange server account. Using an Android 2.1 device (Evo). "Exchange email synchronization is disabled". I can send outbound messages, but new emails are not coming in. Anyone know what would cause this error? Thanks, Kyle

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  • How to set resolution on mplayer with libcaca?

    - by AndrejaKo
    I'm using mplayer and libcaca on Gentoo. My framebuffer (uvesafb) is running at 1920x1200 (I don't know how many characters that is) and mplayer has problems filling up the screen, so video and audio lose synchronization. I'm looking for ways to improve performance. The most obvious solution would be to decrease resolution of mplayer, so I'm looking for ways to do that. Any other performance tips would be appriciated.

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  • GTD tool for Mac OS X and iPhone?

    - by harald
    I am looking for a GTD (getting things done) tool, which there is a OS X and an iPhone app available. I don't want any web based stuff, but native applications. The Mac application needs some functionality for synchronization with the iPhone app. Are there any GTD apps, which fit my requirements?

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  • Where to find Ubuntu One logs

    - by Stéphane
    Ubuntu one does not synchronize files since I upgraded from 9.10 to 10.04. The preferences panel keeps showing "Synchronization in progress...", but files are not downloaded from the repository. It does not show any error message. Where do I find the programm logs, where I can investigate my problem?

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  • synchronous network audio

    - by intuited
    I'd like to have an audio transmission shared among computers on a LAN. Although there are various systems to do this -- shoutcast/icecast, pulseaudio, etc. -- I'm not aware of any that provide synchronization. I'd like to have different computers in the house playing the same audio, and have the same sample playing at the same time. Is there a system which can do this?

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  • timezone setting per virtual host

    - by garry
    I am trying to test functionality related to timezone handling/conversion during synchronization between two of my test servers (currently they are running on same mashine). Is it possible to set up hosts so one will be running, say, by London time, and the other by Moscow? Web applications running on both servers are written on Perl.

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  • Can I sync my Tomboy notes from Windows through Ubuntu One?

    - by badp
    I have setup my Ubuntu machine to synchronize Tomboy notes with the Ubuntu One service. I'm now trying Tomboy on Windows and it would be great to have it sync with Ubuntu One. However, while Tomboy for Ubuntu does expose a 'Ubuntu One' service for synchronization, version 1.2.0 of Tomboy for Windows does not. I can, however, use a "Tomboy Web" service. Does Ubuntu One behave as a Tomboy Web service and how would I configure it to do so?

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  • route53 for multiple identical domains

    - by Yaniv Aknin
    My main domain is example.com, but also bought example.org and example.net. I've configured my webservers at *.example.com to handle requests from the other domains and redirect them correctly to example.com, but I'd rather not re-configure all my DNS records at example.org and example.net to be the same as example.com. Other than writing some ugly synchronization script, what should I do to have route53 answer queries against my "other" domains with the same data from the "main" domain?

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  • Data replication between two web nodes

    - by HTF
    I have Wordpress installation running on two web servers (Nginx). There is unidirectional synchronization from server A to server B and I'm using lsyncd for this purpose. with his configuration I have to add blog posts from the first web server so the data is replicated to the second one - how I can force access to Wordpress back-end only from the first web server? Please note that both servers have the same domain for Wordpress. Regards

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