natural sort - Page 291

Achieving Zero Downtime Deployment

- by MattW

I am trying to achieve zero downtime deployments so I can deploy less during off hours and more during "slower" hours - or anytime, in theory. My current setup, somewhat simplified: Web Server A (.NET App) Web Server B (.NET App) Database Server (SQL Server) My current deployment process: "Stop" the sites on both Web Server A and B Upgrade the database schema for the version of the app being deployed Update Web Server A Update Web Server B Bring everything back online Current Problem This leads to a small amount of downtime each month - about 30 mins. I do this during off hours, so it isn't a huge problem - but it is something I'd like to get away from. Also - there is no way to really go 'back'. I don't generally make rollback DB scripts - only upgrade scripts. Leveraging The Load Balancer I'd love to be able to upgrade one Web Server at a time. Take Web Server A out of the load balancer, upgrade it, put it back online, then repeat for Web Server B. The problem is the database. Each version of my software will need to execute against a different version of the database - so I am sort of "stuck". Possible Solution A current solution I am considering is adopting the following rules: Never delete a database table. Never delete a database column. Never rename a database column. Never reorder a column. Every stored procedure must be versioned. Meaning - 'spFindAllThings' will become 'spFindAllThings_2' when it is edited. Then it becomes 'spFindAllThings_3' when edited again. Same rule applies to views. While, this seems a bit extreme - I think it solves the problem. Each version of the application will be hitting the DB in a non breaking way. The code expects certain results from the views/stored procedures - and this keeps that 'contract' valid. The problem is - it just seeps sloppy. I know I can clean up old stored procedures after the app is deployed for awhile, but it just feels dirty. Also - it depends on all of the developers following these rule, which will mostly happen, but I imagine someone will make a mistake. Finally - My Question Is this sloppy or hacky? Is anybody else doing it this way? How are other people solving this problem?

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Writing the tests for FluentPath

- by Bertrand Le Roy

Writing the tests for FluentPath is a challenge. The library is a wrapper around a legacy API (System.IO) that wasn’t designed to be easily testable. If it were more testable, the sensible testing methodology would be to tell System.IO to act against a mock file system, which would enable me to verify that my code is doing the expected file system operations without having to manipulate the actual, physical file system: what we are testing here is FluentPath, not System.IO. Unfortunately, that is not an option as nothing in System.IO enables us to plug a mock file system in. As a consequence, we are left with few options. A few people have suggested me to abstract my calls to System.IO away so that I could tell FluentPath – not System.IO – to use a mock instead of the real thing. That in turn is getting a little silly: FluentPath already is a thin abstraction around System.IO, so layering another abstraction between them would double the test surface while bringing little or no value. I would have to test that new abstraction layer, and that would bring us back to square one. Unless I’m missing something, the only option I have here is to bite the bullet and test against the real file system. Of course, the tests that do that can hardly be called unit tests. They are more integration tests as they don’t only test bits of my code. They really test the successful integration of my code with the underlying System.IO. In order to write such tests, the techniques of BDD work particularly well as they enable you to express scenarios in natural language, from which test code is generated. Integration tests are being better expressed as scenarios orchestrating a few basic behaviors, so this is a nice fit. The Orchard team has been successfully using SpecFlow for integration tests for a while and I thought it was pretty cool so that’s what I decided to use. Consider for example the following scenario: Scenario: Change extension Given a clean test directory When I change the extension of bar\notes.txt to foo Then bar\notes.txt should not exist And bar\notes.foo should exist This is human readable and tells you everything you need to know about what you’re testing, but it is also executable code. What happens when SpecFlow compiles this scenario is that it executes a bunch of regular expressions that identify the known Given (set-up phases), When (actions) and Then (result assertions) to identify the code to run, which is then translated into calls into the appropriate methods. Nothing magical. Here is the code generated by SpecFlow: [NUnit.Framework.TestAttribute()] [NUnit.Framework.DescriptionAttribute("Change extension")] public virtual void ChangeExtension() { TechTalk.SpecFlow.ScenarioInfo scenarioInfo = new TechTalk.SpecFlow.ScenarioInfo("Change extension", ((string[])(null))); #line 6 this.ScenarioSetup(scenarioInfo); #line 7 testRunner.Given("a clean test directory"); #line 8 testRunner.When("I change the extension of " + "bar\\notes.txt to foo"); #line 9 testRunner.Then("bar\\notes.txt should not exist"); #line 10 testRunner.And("bar\\notes.foo should exist"); #line hidden testRunner.CollectScenarioErrors();} The #line directives are there to give clues to the debugger, because yes, you can put breakpoints into a scenario: The way you usually write tests with SpecFlow is that you write the scenario first, let it fail, then write the translation of your Given, When and Then into code if they don’t already exist, which results in running but failing tests, and then you write the code to make your tests pass (you implement the scenario). In the case of FluentPath, I built a simple Given method that builds a simple file hierarchy in a temporary directory that all scenarios are going to work with: [Given("a clean test directory")] public void GivenACleanDirectory() { _path = new Path(SystemIO.Path.GetTempPath()) .CreateSubDirectory("FluentPathSpecs") .MakeCurrent(); _path.GetFileSystemEntries() .Delete(true); _path.CreateFile("foo.txt", "This is a text file named foo."); var bar = _path.CreateSubDirectory("bar"); bar.CreateFile("baz.txt", "bar baz") .SetLastWriteTime(DateTime.Now.AddSeconds(-2)); bar.CreateFile("notes.txt", "This is a text file containing notes."); var barbar = bar.CreateSubDirectory("bar"); barbar.CreateFile("deep.txt", "Deep thoughts"); var sub = _path.CreateSubDirectory("sub"); sub.CreateSubDirectory("subsub"); sub.CreateFile("baz.txt", "sub baz") .SetLastWriteTime(DateTime.Now); sub.CreateFile("binary.bin", new byte[] {0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0xFF}); } Then, to implement the scenario that you can read above, I had to write the following When: [When("I change the extension of (.*) to (.*)")] public void WhenIChangeTheExtension( string path, string newExtension) { var oldPath = Path.Current.Combine(path.Split('\\')); oldPath.Move(p => p.ChangeExtension(newExtension)); } As you can see, the When attribute is specifying the regular expression that will enable the SpecFlow engine to recognize what When method to call and also how to map its parameters. For our scenario, “bar\notes.txt” will get mapped to the path parameter, and “foo” to the newExtension parameter. And of course, the code that verifies the assumptions of the scenario: [Then("(.*) should exist")] public void ThenEntryShouldExist(string path) { Assert.IsTrue(_path.Combine(path.Split('\\')).Exists); } [Then("(.*) should not exist")] public void ThenEntryShouldNotExist(string path) { Assert.IsFalse(_path.Combine(path.Split('\\')).Exists); } These steps should be written with reusability in mind. They are building blocks for your scenarios, not implementation of a specific scenario. Think small and fine-grained. In the case of the above steps, I could reuse each of those steps in other scenarios. Those tests are easy to write and easier to read, which means that they also constitute a form of documentation. Oh, and SpecFlow is just one way to do this. Rob wrote a long time ago about this sort of thing (but using a different framework) and I highly recommend this post if I somehow managed to pique your interest: http://blog.wekeroad.com/blog/make-bdd-your-bff-2/ And this screencast (Rob always makes excellent screencasts): http://blog.wekeroad.com/mvc-storefront/kona-3/ (click the “Download it here” link)

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MVC data binding

- by user441521

I'm using MVC but I've read that MVVM is sort of about data binding and having pure markup in your views that data bind back to the backend via the data-* attributes. I've looked at knockout but it looks pretty low level and I feel like I can make a library that does this and is much easier to use where basically you only need to call 1 javascript function that will data bind your entire page because of the data-* attributes you assign to html elements. The benefits of this (that I see) is that your view is 100% decoupled from your back-end so that a given view never has to be changed if your back-end changes (ie for asp.net people no more razor in your view that makes your view specific to MS). My question would be, I know there is knockout out there but are there any others that provide this data binding functionality for MVC type applications? I don't want to recreate something that may already exist but I want to make something "better" and easier to use than knockout. To give an example of what I mean here is all the code one would need to get data binding in my library. This isn't final but just showing the idea that all you have to do is call 1 javascript function and set some data-* attribute values and everything ties together. Is this worth seeing through? <script> $(function () { // this is all you have to call to make databinding for POST or GET to work DataBind(); }); </script> <form id="addCustomer" data-bind="Customer" data-controller="Home" data-action="CreateCustomer"> Name: <input type="text" data-bind="Name" data-bind-type="text" /> Birthday: <input type="text" data-bind="Birthday" data-bind-type="text" /> Address: <input type="text" data-bind="Address" data-bind-type="text" /> <input type="submit" value="Save" id="btnSave" /> </form> ================================================= // controller action [HttpPost] public string CreateCustomer(Customer customer) { if(customer.Name == "Rick") return "success"; return "failure"; } // model public class Customer { public string Name { get; set; } public DateTime Birthday { get; set; } public string Address { get; set; } }

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In Case You Weren’t There: Blogwell NYC

- by Mike Stiles

0 0 1 1009 5755 Vitrue 47 13 6751 14.0 Normal 0 false false false EN-US JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman";} Your roving reporter roved out to another one of Socialmedia.org’s fantastic Blogwell events, this time in NYC. As Central Park and incredible weather beckoned, some of the biggest brand names in the world gathered to talk about how they’re incorporating social into marketing and CRM, as well as extending social across their entire organizations internally. Below we present a collection of the live tweets from many of the key sessions GE @generalelectricJon Lombardo, Leader of Social Media COE How GE builds and extends emotional connections with consumers around health and reaps the benefits of increased brand equity in the process. GE has a social platform around Healthyimagination to create better health for people. If you and a friend are trying to get healthy together, you’ll do better. Health is inherently. Get health challenges via Facebook and share with friends to achieve goals together. They’re creating an emotional connection around the health context. You don’t influence people at large. Your sphere of real influence is around 5-10 people. They find relevant conversations about health on Twitter and engage sounding like a friend, not a brand. Why would people share on behalf of a brand? Because you tapped into an activity and emotion they’re already having. To create better habits in health, GE gave away inexpensive, relevant gifts related to their goals. Create the context, give the relevant gift, get social acknowledgment for giving it. What you get when you get acknowledgment for your engagement and gift is user generated microcontent. GE got 12,000 unique users engaged and 1400 organic posts with the healthy gift campaign. The Dow Chemical Company @DowChemicalAbby Klanecky, Director of Digital & Social Media Learn how Dow Chemical is finding, training, and empowering their scientists to be their storytellers in social media. There are 1m jobs coming open in science. Only 200k are qualified for them. Dow Chemical wanted to use social to attract and talk to scientists. Dow Chemical decided to use real scientists as their storytellers. Scientists are incredibly passionate, the key ingredient of a great storyteller. Step 1 was getting scientists to focus on a few platforms, blog, Twitter, LinkedIn. Dow Chemical social flow is Core Digital Team - #CMs – ambassadors – advocates. The scientists were trained in social etiquette via practice scenarios. It’s not just about sales. It’s about growing influence and the business. Dow Chemical trained about 100 scientists, 55 are active and there’s a waiting list for the next sessions. In person social training produced faster results and better participation. Sometimes you have to tell pieces of the story instead of selling your execs on the whole vision. Social Media Ethics Briefing: Staying Out of TroubleAndy Sernovitz, CEO @SocialMediaOrg How do we get people to share our message for us? We have to have their trust. The difference between being honest and being sleazy is disclosure. Disclosure does not hurt the effectiveness of your marketing. No one will get mad if you tell them up front you’re a paid spokesperson for a company. It’s a legal requirement by the FTC, it’s the law, to disclose if you’re being paid for an endorsement. Require disclosure and truthfulness in all your social media outreach. Don’t lie to people. Monitor the conversation and correct misstatements. Create social media policies and training programs. If you want to stay safe, never pay cash for social media. Money changes everything. As soon as you pay, it’s not social media, it’s advertising. Disclosure, to the feds, means clear, conspicuous, and understandable to the average reader. This phrase will keep you in the clear, “I work for ___ and this is my personal opinion.” Who are you? Were you paid? Are you giving an honest opinion based on a real experience? You as a brand are responsible for what an agency or employee or contactor does in your behalf. SocialMedia.org makes available a Disclosure Best Practices Toolkit. Socialmedia.org/disclosure. The point is to not ethically mess up and taint social media as happened to e-mail. Not only is the FTC cracking down, so is Google and Facebook. Visa @VisaNewsLucas Mast, Senior Business Leader, Global Corporate Social Media Visa built a mobile studio for the Olympics for execs and athletes. They wanted to do postcard style real time coverage of Visa’s Olympics sponsorships, and on a shoestring. Challenges included Olympic rules, difficulty getting interviews, time zone trouble, and resourcing. Another problem was they got bogged down with their own internal approval processes. Despite all the restrictions, they created and published a variety of and fair amount of content. They amassed 1000+ views of videos posted to the Visa Communication YouTube channel. Less corporate content yields more interest from media outlets and bloggers. They did real world video demos of how their products work in the field vs. an exec doing a demo in a studio. Don’t make exec interview videos dull and corporate. Keep answers short, shoot it in an interesting place, do takes until they’re comfortable and natural. Not everything will work. Not everything will get a retweet. But like the lottery, you can’t win if you don’t play. Promoting content is as important as creating it. McGraw-Hill Companies @McGrawHillCosPatrick Durando, Senior Director of Global New Media McGraw-Hill has 26,000 employees. McGraw-Hill created a social intranet called Buzz. Intranets create operational efficiency, help product dev, facilitate crowdsourcing, and breaks down geo silos. Intranets help with talent development, acquisition, retention. They replaced the corporate directory with their own version of LinkedIn. The company intranet has really cut down on the use of email. Long email threats become organized, permanent social discussions. The intranet is particularly useful in HR for researching and getting answers surrounding benefits and policies. Using a profile on your company intranet can establish and promote your internal professional brand. If you’re going to make an intranet, it has to look great, work great, and employees are going have to want to go there. You can’t order them to like it.

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Getting from a user-story to code while using TDD (scrum)

- by Ittai

I'm getting into scrum and TDD and I think I have some confusion which I'd like to get your feedback about. Let's assume I have a user-story in my backlog, in order for me to start developing it as part of TDD I need to have requirements, right so far? Is it true to say that the product manager and the QA should be responsible for taking the user-story and breaking it down to acceptance tests? I think the above is true since the acceptance tests need to be formal, so they can be used as tests, but also human readable so that the product can approve they are the requirements, right? Is it also true that I later take these acceptance tests and use them as my requirements, i.e. they are a set of use-cases which I implement (through TDD)? I hope I'm not making too much of a mess but that's the current flow I have in mind right now. Update I think my initial intentions were unclear so I'll try to rephrase. I want to know more details about the scrum flow of turning a user-story into code while using TDD. The starting point is obvious, a user surfaces a need (or the user's representative as the product) which is a short 1-2 lines description in the known format and that is added to the product backlog. When there is a spring planning meeting user-stories are taken from the backlog and assigned to developers. In order for a developer to write code they need requirements (especially in TDD since the requirements are what the tests are derived from). When, by whom and to which format are the requirements compiled? What I had in mind was that the product and QA define the requirements via acceptance tests (I'm thinking of automatic using FitNesse or the sort but that's not the core I think) which help to serve 2 purposes at the same time: They define "Done" properly. They give a developer something to derive tests from. I wasn't sure when these were written (before the sprint they're picked then that might be a waste since additional information will arrive or the story won't be picked, during the iteration then the developer might get stuck waiting for them...)

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How to implement line of sight restriction in actionscript?

- by Michiel Standaert

I have a problem with a game i am programming. I am making some sort of security game and i would like to have some visual line of sight. The problem is that i can't restrict my line of sight so my cops can't see through the walls. Below you find the design, in which they can look through windows, but not walls. Further below you find an illustration of what my problem is exactly. this is what it looks like now. As you can see, the cops can see through walls. This is the map i would want to use to restrict the line of sight. So the way i am programming the line of sight now is just by calculating some points and drawing the sight accordingly, as shown below. Note that i also check for a hittest using bitmapdata to check whether or not my player has been spotted by any of the cops. private function setSight(e:Event=null):Boolean { g = copCanvas.graphics; g.clear(); for each(var cop:Cop in copCanvas.getChildren()) { var _angle:Number = cop.angle; var _radians:Number = (_angle * Math.PI) / 180; var _radius:Number = 50; var _x1:Number = cop.x + (cop.width/2); var _y1:Number = cop.y + (cop.height/2); var _baseX:Number = _x1 + (Math.cos(_radians) * _radius); var _baseY:Number = _y1 - (Math.sin(_radians) * _radius); var _x2:Number = _baseX + (25 * Math.sin(_radians)); var _y2:Number = _baseY + (25 * Math.cos(_radians)); var _x3:Number = _baseX - (25 * Math.sin(_radians)); var _y3:Number = _baseY - (25 * Math.cos(_radians)); g.beginFill(0xff0000, 0.3); g.moveTo(_x1, _y1); g.lineTo(_x2, _y2); g.lineTo(_x3, _y3); g.endFill(); } var _cops:BitmapData = new BitmapData(width, height, true, 0); _cops.draw(copCanvas); var _bmpd:BitmapData = new BitmapData(10, 10, true, 0); _bmpd.draw(me); if(_cops.hitTest(new Point(0, 0), 10, _bmpd, new Point(me.x, me.y), 255)) { gameover.alpha = 1; setTimeout(function():void{ gameover.alpha = 0; }, 5000); stop(); return true; } return false; } So now my question is: Is there someone who knows how to restrict the view so that the cops can't look through the walls? Thanks a lot in advance. ps: i have already looked at this tutorial by emanuele feronato, but i can't use the code to restric the visual line of sight.

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Detecting if someone is in a room in your house and sending you an email.

- by mbcrump

Let me setup this scenario: You are selling your house. You have small children. (Possibly 2 rug rats or more) The real estate company calls and says they have a showing for your house between the hours of 3pm-6pm. You have to keep the children occupied. You realize this is the 5th time you have shown your house this week. What is a programmer to do?……Setup a webcam, find a motion detection software that has support to launch a program and of course, Visual Studio 2010. First, comes the tools Some sort of webcam, I chose the WinBook because a friend of mine loaned it to me. It is a basic USB2.0 camera that supports 640x480 without software. Next up was find webcam software that supports launching a program. WebcamXP support this. VS 2010 Console Application. A cell phone that you can check your email. You may be asking, why write code to send the email when a lot of commercial software motion detection packages include that as base functionality. Well, first it cost money and second I don’t want the picture of the person as that probably invades privacy and as a future buyer, I don’t want someone recording me in their house. Now onto the show... First, the code part. We are going to create a VS2010 or whatever version you have installed and use the following code snippet. Code Snippet using System; using System.Net.Mail; using System.Net; namespace MotionDetectionEmailer { class Program { static void Main(string[] args) { try { MailMessage m = new MailMessage ("[email protected]", "[email protected]", "Motion Detected at " + DateTime.Now, "Someone is in the downstairs basement."); SmtpClient client = new SmtpClient("smtp.charter.net"); client.Credentials = new NetworkCredential("mbcrump", "NOTTELLINGYOU"); client.Send(m); } catch (SmtpException ex) { Console.WriteLine("Who cares?? " + ex.ToString()); } } } } Second, Download and install wecamxp and select the option to launch an external program and you are finished. Now, when you are at MCDonalds and can check your email on your phone, you will see when they entered the house and you can go back home without waiting the full 3 hours. --- NICE!

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AI for a mixed Turn Based + Real Time battle system - Something "Gambit like" the right approach?

- by Jason L.

This is maybe a question that's been asked 100 times 1,000 different ways. I apologize for that :) I'm in the process of building the AI for a game I'm working on. The game is a turn based one, in the vein of Final Fantasy but also has a set of things that happen in real time (reactions). I've experimented with FSM, HFSMs, and Behavior Trees. None of them felt "right" to me and all felt either too limiting or too generic / big. The idea I'm toying with now is something like a "Rules engine" that could be likened to the Gambit system from Final Fantasy 12. I would have a set of predefined personalities. Each of these personalities would have a set of conditions it would check on each event (Turn start, time to react, etc). These conditions would be priority ordered, and the first one that returns true would be the action I take. These conditions can also point to a "choice" action, which is just an action that will make a choice based on some Utility function. Sort of a mix of FSM/HFSM and a Utility Function approach. So, a "gambit" with the personality of "Healer" may look something like this: (ON) Ally HP = 0% - Choose "Relife" spell (ON) Ally HP < 50% - Choose Heal spell (ON) Self HP < 65% - Choose Heal spell (ON) Ally Debuff - Choose Debuff Removal spell (ON) Ally Lost Buff - Choose Buff spell Likewise, a "gambit" with the personality of "Agressor" may look like this: (ON) Foe HP < 10% - Choose Attack skill (ON) Foe any - Choose target - Choose Attack skill (ON) Self Lost Buff - Choose Buff spell (ON) Foe HP = 0% - Taunt the player What I like about this approach is it makes sense in my head. It also would be extremely easy to build an "AI Editor" with an approach like this. What I'm worried about is.. would it be too limiting? Would it maybe get too complicated? Does anyone have any experience with AIs in Turn Based games that could maybe provide me some insight into this approach.. or suggest a different approach? Many thanks in advance!!!

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Open the SQL Server Error Log with PowerShell

- by BuckWoody

Using the Server Management Objects (SMO) library, you don’t even need to have the SQL Server 2008 PowerShell Provider to read the SQL Server Error Logs – in fact, you can use regular old everyday PowerShell. Keep in mind you will need the SMO libraries – which can be installed separately or by installing the Client Tools from the SQL Server install media. You could search for errors, store a result as a variable, or act on the returned values in some other way. Replace the Machine Name with your server and Instance Name with your instance, but leave the quotes, to make this work on your system: [reflection.assembly]::LoadWithPartialName("Microsoft.SqlServer.Smo") $machineName = "UNIVAC" $instanceName = "Production" $sqlServer = new-object ("Microsoft.SqlServer.Management.Smo.Server") "$machineName\$instanceName" $sqlServer.ReadErrorLog() Want to search for something specific, like the word “Error”? Replace the last line with this: $sqlServer.ReadErrorLog() | where {$_.Text -like "Error*"} Script Disclaimer, for people who need to be told this sort of thing: Never trust any script, including those that you find here, until you understand exactly what it does and how it will act on your systems. Always check the script on a test system or Virtual Machine, not a production system. Yes, there are always multiple ways to do things, and this script may not work in every situation, for everything. It’s just a script, people. All scripts on this site are performed by a professional stunt driver on a closed course. Your mileage may vary. Void where prohibited. Offer good for a limited time only. Keep out of reach of small children. Do not operate heavy machinery while using this script. If you experience blurry vision, indigestion or diarrhea during the operation of this script, see a physician immediately. Share this post: email it! | bookmark it! | digg it! | reddit! | kick it! | live it!

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Monitoring Your Servers

- by Grant Fritchey

If you are the DBA in a large scale enterprise, you’re probably already monitoring your servers for up-time and performance. But if you work for a medium-sized business, a small shop, or even a one-man operation, chances are pretty good that you’re not doing that sort of monitoring. You know that you’re supposed to be doing it, but other things, more important at-the-moment things, keep getting in the way. After all, which is more important, some monitoring or backup testing? Backup testing, of course. Monitoring is frequently one of those things that you do when can get around to it. Well, as you can see at the right, I have your round tuit ready to go. What if I told you that you could get monitoring on your servers for up-time, job completion, performance, all the standard stuff? And what if I told you that you wouldn’t need to install and configure another server in your environment to get it done? And what if I told you that you’d be able to set up and customize your alerts so you could know if your server was offline or a drive was full? Almost nothing for you to do, and you’ll have a full-blown monitoring process. Sounds to good to be true doesn’t it? Well, it’s coming. We’re creating an online, remote, monitoring system here at Red Gate. You’ll be able to use our SQL Monitor tool (which you can see here, monitoring SQL Server Central in real time) to keep track of your systems, but without having to set up a server and a database for storing the information collected. Instead, we’re taking advantage of services available through the internet to enable collection and storage of this information remotely, off your systems. All you have to do is install a piece of software that will communicate between our service and your servers and you’ll be off and running. It’s that easy. Before you get too excited, let me break the news that this is the near future I’m talking about. We’re setting up the program and there’s a sign-up you can use to get in on the initial tests.

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Space partitioning when everything is moving

- by Roy T.

Background Together with a friend I'm working on a 2D game that is set in space. To make it as immersive and interactive as possible we want there to be thousands of objects freely floating around, some clustered together, others adrift in empty space. Challenge To unburden the rendering and physics engine we need to implement some sort of spatial partitioning. There are two challenges we have to overcome. The first challenge is that everything is moving so reconstructing/updating the data structure has to be extremely cheap since it will have to be done every frame. The second challenge is the distribution of objects, as said before there might be clusters of objects together and vast bits of empty space and to make it even worse there is no boundary to space. Existing technologies I've looked at existing techniques like BSP-Trees, QuadTrees, kd-Trees and even R-Trees but as far as I can tell these data structures aren't a perfect fit since updating a lot of objects that have moved to other cells is relatively expensive. What I've tried I made the decision that I need a data structure that is more geared toward rapid insertion/update than on giving back the least amount of possible hits given a query. For that purpose I made the cells implicit so each object, given it's position, can calculate in which cell(s) it should be. Then I use a HashMap that maps cell-coordinates to an ArrayList (the contents of the cell). This works fairly well since there is no memory lost on 'empty' cells and its easy to calculate which cells to inspect. However creating all those ArrayLists (worst case N) is expensive and so is growing the HashMap a lot of times (although that is slightly mitigated by giving it a large initial capacity). Problem OK so this works but still isn't very fast. Now I can try to micro-optimize the JAVA code. However I'm not expecting too much of that since the profiler tells me that most time is spent in creating all those objects that I use to store the cells. I'm hoping that there are some other tricks/algorithms out there that make this a lot faster so here is what my ideal data structure looks like: The number one priority is fast updating/reconstructing of the entire data structure Its less important to finely divide the objects into equally sized bins, we can draw a few extra objects and do a few extra collision checks if that means that updating is a little bit faster Memory is not really important (PC game)

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Curing the Database-Application mismatch

- by Phil Factor

If an application requires access to a database, then you have to be able to deploy it so as to be version-compatible with the database, in phase. If you can deploy both together, then the application and database must normally be deployed at the same version in which they, together, passed integration and functional testing. When a single database supports more than one application, then the problem gets more interesting. I’ll need to be more precise here. It is actually the application-interface definition of the database that needs to be in a compatible ‘version’. Most databases that get into production have no separate application-interface; in other words they are ‘close-coupled’. For this vast majority, the whole database is the application-interface, and applications are free to wander through the bowels of the database scot-free. If you’ve spurned the perceived wisdom of application architects to have a defined application-interface within the database that is based on views and stored procedures, any version-mismatch will be as sensitive as a kitten. A team that creates an application that makes direct access to base tables in a database will have to put a lot of energy into keeping Database and Application in sync, to say nothing of having to tackle issues such as security and audit. It is not the obvious route to development nirvana. I’ve been in countless tense meetings with application developers who initially bridle instinctively at the apparent restrictions of being ‘banned’ from the base tables or routines of a database. There is no good technical reason for needing that sort of access that I’ve ever come across. Everything that the application wants can be delivered via a set of views and procedures, and with far less pain for all concerned: This is the application-interface. If more than zero developers are creating a database-driven application, then the project will benefit from the loose-coupling that an application interface brings. What is important here is that the database development role is separated from the application development role, even if it is the same developer performing both roles. The idea of an application-interface with a database is as old as I can remember. The big corporate or government databases generally supported several applications, and there was little option. When a new application wanted access to an existing corporate database, the developers, and myself as technical architect, would have to meet with hatchet-faced DBAs and production staff to work out an interface. Sure, they would talk up the effort involved for budgetary reasons, but it was routine work, because it decoupled the database from its supporting applications. We’d be given our own stored procedures. One of them, I still remember, had ninety-two parameters. All database access was encapsulated in one application-module. If you have a stable defined application-interface with the database (Yes, one for each application usually) you need to keep the external definitions of the components of this interface in version control, linked with the application source, and carefully track and negotiate any changes between database developers and application developers. Essentially, the application development team owns the interface definition, and the onus is on the Database developers to implement it and maintain it, in conformance. Internally, the database can then make all sorts of changes and refactoring, as long as source control is maintained. If the application interface passes all the comprehensive integration and functional tests for the particular version they were designed for, nothing is broken. Your performance-testing can ‘hang’ on the same interface, since databases are judged on the performance of the application, not an ‘internal’ database process. The database developers have responsibility for maintaining the application-interface, but not its definition, as they refactor the database. This is easily tested on a daily basis since the tests are normally automated. In this setting, the deployment can proceed if the more stable application-interface, rather than the continuously-changing database, passes all tests for the version of the application. Normally, if all goes well, a database with a well-designed application interface can evolve gracefully without changing the external appearance of the interface, and this is confirmed by integration tests that check the interface, and which hopefully don’t need to be altered at all often. If the application is rapidly changing its ‘domain model’ in the light of an increased understanding of the application domain, then it can change the interface definitions and the database developers need only implement the interface rather than refactor the underlying database. The test team will also have to redo the functional and integration tests which are, of course ‘written to’ the definition. The Database developers will find it easier if these tests are done before their re-wiring job to implement the new interface. If, at the other extreme, an application receives no further development work but survives unchanged, the database can continue to change and develop to keep pace with the requirements of the other applications it supports, and needs only to take care that the application interface is never broken. Testing is easy since your automated scripts to test the interface do not need to change. The database developers will, of course, maintain their own source control for the database, and will be likely to maintain versions for all major releases. However, this will not need to be shared with the applications that the database servers. On the other hand, the definition of the application interfaces should be within the application source. Changes in it have to be subject to change-control procedures, as they will require a chain of tests. Once you allow, instead of an application-interface, an intimate relationship between application and database, we are in the realms of impedance mismatch, over and above the obvious security problems. Part of this impedance problem is a difference in development practices. Whereas the application has to be regularly built and integrated, this isn’t necessarily the case with the database. An RDBMS is inherently multi-user and self-integrating. If the developers work together on the database, then a subsequent integration of the database on a staging server doesn’t often bring nasty surprises. A separate database-integration process is only needed if the database is deliberately built in a way that mimics the application development process, but which hampers the normal database-development techniques. This process is like demanding a official walking with a red flag in front of a motor car. In order to closely coordinate databases with applications, entire databases have to be ‘versioned’, so that an application version can be matched with a database version to produce a working build without errors. There is no natural process to ‘version’ databases. Each development project will have to define a system for maintaining the version level. A curious paradox occurs in development when there is no formal application-interface. When the strains and cracks happen, the extra meetings, bureaucracy, and activity required to maintain accurate deployments looks to IT management like work. They see activity, and it looks good. Work means progress. Management then smile on the design choices made. In IT, good design work doesn’t necessarily look good, and vice versa.

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Interviews: Going Beyond the Technical Quiz

- by Tony Davis

All developers will be familiar with the basic format of a technical interview. After a bout of CV-trawling to gauge basic experience, strengths and weaknesses, the interview turns technical. The whiteboard takes center stage and the challenge is set to design a function or query, or solve what on the face of it might seem a disarmingly simple programming puzzle. Most developers will have experienced those few panic-stricken moments, when one’s mind goes as blank as the whiteboard, before un-popping the marker pen, and hopefully one’s mental functions, to work through the problem. It is a way to probe the candidate’s knowledge of basic programming structures and techniques and to challenge their critical thinking. However, these challenges or puzzles, often devised by some of the smartest brains in the development team, have a tendency to become unnecessarily ‘tricksy’. They often seem somewhat academic in nature. While the candidate straight out of IT school might breeze through the construction of a Markov chain, a candidate with bags of practical experience but less in the way of formal training could become nonplussed. Also, a whiteboard and a marker pen make up only a very small part of the toolkit that a programmer will use in everyday work. I remember vividly my first job interview, for a position as technical editor. It went well, but after the usual CV grilling and technical questions, I was only halfway there. Later, they sat me alongside a team of editors, in front of a computer loaded with MS Word and copy of SQL Server Query Analyzer, and my task was to edit a real chapter for a real SQL Server book that they planned to publish, including validating and testing all the code. It was a tough challenge but I came away with a sound knowledge of the sort of work I’d do, and its context. It makes perfect sense, yet my impression is that many organizations don’t do this. Indeed, it is only relatively recently that Red Gate started to move over to this model for developer interviews. Now, instead of, or perhaps in addition to, the whiteboard challenges, the candidate can expect to sit with their prospective team, in front of Visual Studio, loaded with all the useful tools in the developer’s kit (ReSharper and so on) and asked to, for example, analyze and improve a real piece of software. The same principles should apply when interviewing for a database positon. In addition to the usual questions challenging the candidate’s knowledge of such things as b-trees, object permissions, database recovery models, and so on, sit the candidate down with the other database developers or DBAs. Arm them with a copy of Management Studio, and a few other tools, then challenge them to discover the flaws in a stored procedure, and improve its performance. Or present them with a corrupt database and ask them to get the database back online, and discover the cause of the corruption.

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Poll Results: Foreign Key Constraints

- by Darren Gosbell

A few weeks ago I did the following post asking people – if they used foreign key constraints in their star schemas. The poll is still open if you are interested in adding to it, but here is what the chart looks like as of today. (at the bottom of the poll itself there is a link to the live results, unfortunately I cannot link the live results in here as the blogging platform blocks the required javascript) Interestingly the results are fairly even. Of the 78 respondents, fractionally over half at least aim to start with referential integrity in their star schemas. I did not want to influence the results by sharing my opinion, but my personal preference is to always aim to have foreign key constraints. But at the same time, I am pragmatic about it, I do have projects where for various reasons some constraints are not defined. And I also have other designs that I have inherited, where it would just be too much work to go back and add foreign key constraints. If you are going to implement foreign keys in your star schema, they really need to be there at the start. In fact this poll was was the result of a feature request for BIDSHelper asking for a feature to check for null/missing foreign keys and I am entirely convinced that BIDS is the wrong place for this sort of functionality. BIDS is a design tool, your data needs to be constantly checked for consistency. It's not that I think that it's impossible to get a design working without foreign key constraints, but I like the idea of failing as soon as possible if there is an error and enforcing foreign key constraints lets me "fail early" if there are constancy issues with my data. By far the biggest concern with foreign keys is performance and I suppose I'm curious as to how often people actually measure and quantify this. I worked on a project a number of years ago that had very large data volumes and we did find that foreign key constraints did have a measurable impact, but what we did was to disable the constraints before loading the data, then enabled and checked them afterwards. This saved as time (although not as much as not having constraints at all), but still let us know early in the process if there were any consistency issues. For the people that do not have consistent data, if you have ETL processes that you control that are building your star schema which you also control, then to be blunt you only have yourself to blame. It is the job of the ETL process to make the data consistent. There are techniques for handling situations like missing data as well as early and late arriving data. Ralph Kimball's book – The Data Warehouse Toolkit goes through some design patterns for handling data consistency. Having foreign key relationships can also help the relational engine to optimize queries as noted in this recent blog post by Boyan Penev

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rkhunter 1.4 different results than version before?

- by dschinn1001

with rkhunter version before ubuntu-update from 12.04 to 12.10 I had NOT these warnings like listed here: Performing file properties checks Checking for prerequisites [ Warning ] /usr/sbin/adduser [ Warning ] /usr/sbin/chroot [ Warning ] /usr/sbin/cron [ Warning ] /usr/sbin/groupadd [ Warning ] /usr/sbin/groupdel [ Warning ] /usr/sbin/groupmod [ Warning ] /usr/sbin/grpck [ Warning ] /usr/sbin/nologin [ Warning ] /usr/sbin/pwck [ Warning ] /usr/sbin/rsyslogd [ Warning ] /usr/sbin/tcpd [ Warning ] /usr/sbin/useradd [ Warning ] /usr/sbin/userdel [ Warning ] /usr/sbin/usermod [ Warning ] /usr/sbin/vipw [ Warning ] /usr/bin/awk [ Warning ] /usr/bin/basename [ Warning ] /usr/bin/chattr [ Warning ] /usr/bin/curl [ Warning ] /usr/bin/cut [ Warning ] /usr/bin/diff [ Warning ] /usr/bin/dirname [ Warning ] /usr/bin/dpkg [ Warning ] /usr/bin/dpkg-query [ Warning ] /usr/bin/du [ Warning ] /usr/bin/env [ Warning ] /usr/bin/file [ Warning ] /usr/bin/find [ Warning ] /usr/bin/GET [ Warning ] /usr/bin/groups [ Warning ] /usr/bin/head [ Warning ] /usr/bin/id [ Warning ] /usr/bin/killall [ Warning ] /usr/bin/last [ Warning ] /usr/bin/lastlog [ Warning ] /usr/bin/ldd [ Warning ] /usr/bin/less [ Warning ] /usr/bin/locate [ Warning ] /usr/bin/logger [ Warning ] /usr/bin/lsattr [ Warning ] /usr/bin/lsof [ Warning ] /usr/bin/lynx [ Warning ] /usr/bin/mail [ Warning ] /usr/bin/md5sum [ Warning ] /usr/bin/mlocate [ Warning ] /usr/bin/newgrp [ Warning ] /usr/bin/passwd [ Warning ] /usr/bin/perl [ Warning ] /usr/bin/pgrep [ Warning ] /usr/bin/pkill [ Warning ] /usr/bin/pstree [ Warning ] /usr/bin/rkhunter [ Warning ] /usr/bin/rpm [ Warning ] /usr/bin/runcon [ Warning ] /usr/bin/sha1sum [ Warning ] /usr/bin/sha224sum [ Warning ] /usr/bin/sha256sum [ Warning ] /usr/bin/sha384sum [ Warning ] /usr/bin/sha512sum [ Warning ] /usr/bin/size [ Warning ] /usr/bin/sort [ Warning ] /usr/bin/stat [ Warning ] /usr/bin/strace [ Warning ] /usr/bin/strings [ Warning ] /usr/bin/sudo [ Warning ] /usr/bin/tail [ Warning ] /usr/bin/test [ Warning ] /usr/bin/top [ Warning ] /usr/bin/touch [ Warning ] /usr/bin/tr [ Warning ] /usr/bin/uniq [ Warning ] /usr/bin/users [ Warning ] /usr/bin/vmstat [ Warning ] /usr/bin/w [ Warning ] /usr/bin/watch [ Warning ] /usr/bin/wc [ Warning ] /usr/bin/wget [ Warning ] /usr/bin/whatis [ Warning ] /usr/bin/whereis [ Warning ] /usr/bin/which [ Warning ] /usr/bin/who [ Warning ] /usr/bin/whoami [ Warning ] /usr/bin/unhide.rb [ Warning ] /usr/bin/gawk [ Warning ] /usr/bin/lwp-request [ Warning ] /usr/bin/heirloom-mailx [ Warning ] /usr/bin/w.procps [ Warning ] /sbin/depmod [ Warning ] /sbin/fsck [ Warning ] /sbin/ifconfig [ Warning ] /sbin/ifdown [ Warning ] /sbin/ifup [ Warning ] /sbin/init [ Warning ] /sbin/insmod [ Warning ] /sbin/ip [ Warning ] /sbin/lsmod [ Warning ] /sbin/modinfo [ Warning ] /sbin/modprobe [ Warning ] /sbin/rmmod [ Warning ] /sbin/route [ Warning ] /sbin/runlevel [ Warning ] /sbin/sulogin [ Warning ] /sbin/sysctl [ Warning ] /bin/bash [ Warning ] /bin/cat [ Warning ] /bin/chmod [ Warning ] /bin/chown [ Warning ] /bin/cp [ Warning ] /bin/date [ Warning ] /bin/df [ Warning ] /bin/dmesg [ Warning ] /bin/echo [ Warning ] /bin/ed [ Warning ] /bin/egrep [ Warning ] /bin/fgrep [ Warning ] /bin/fuser [ Warning ] /bin/grep [ Warning ] /bin/ip [ Warning ] /bin/kill [ Warning ] /bin/less [ Warning ] /bin/login [ Warning ] /bin/ls [ Warning ] /bin/lsmod [ Warning ] /bin/mktemp [ Warning ] /bin/more [ Warning ] /bin/mount [ Warning ] /bin/mv [ Warning ] /bin/netstat [ Warning ] /bin/ping [ Warning ] /bin/ps [ Warning ] /bin/pwd [ Warning ] /bin/readlink [ Warning ] /bin/sed [ Warning ] /bin/sh [ Warning ] /bin/su [ Warning ] /bin/touch [ Warning ] /bin/uname [ Warning ] /bin/which [ Warning ] /bin/dash [ Warning ] It seems that rkhunter 1.4 is oversensitive somehow about changed bin-files ? chkrootkit finds nothing and no warnings too.

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The Business of Winning Innovation: An Exclusive Blog Series

- by Kerrie Foy

"The Business of Winning Innovation” is a series of articles authored by Oracle Agile PLM experts on what it takes to make innovation a successful and lucrative competitive advantage. Our customers have proven Agile PLM applications to be enormously flexible and comprehensive, so we’ve launched this article series to showcase some of the most fascinating, value-packed use cases. In this article by Keith Colonna, we kick-off the series by taking a look at the science side of innovation within the Consumer Products industry and how PLM can help companies innovate faster, cheaper, smarter. This article will review how innovation has become the lifeline for growth within consumer products companies and how certain companies are “winning” by creating a competitive advantage for themselves by taking a more enterprise-wide,systematic approach to “innovation”. Managing the Science of Innovation within the Consumer Products Industry By: Keith Colonna, Value Chain Solution Manager, Oracle The consumer products (CP) industry is very mature and competitive. Most companies within this industry have saturated North America (NA) with their products thus maximizing their NA growth potential. Future growth is expected to come from either expansion outside of North America and/or by way of new ideas and products. Innovation plays an integral role in both of these strategies, whether you’re innovating business processes or the products themselves, and may cause several challenges for the typical CP company, Becoming more innovative is both an art and a science. Most CP companies are very good at the art of coming up with new innovative ideas, but many struggle with perfecting the science aspect that involves the best practice processes that help companies quickly turn ideas into sellable products and services. Symptoms and Causes of Business Pain Struggles associated with the science of innovation show up in a variety of ways, like: · Establishing and storing innovative product ideas and data · Funneling these ideas to the chosen few · Time to market cycle time and on-time launch rates · Success rates, or how often the best idea gets chosen · Imperfect decision making (i.e. the ability to kill projects that are not projected to be winners) · Achieving financial goals · Return on R&D investment · Communicating internally and externally as more outsource partners are added globally · Knowing your new product pipeline and project status These challenges (and others) can be consolidated into three root causes: A lack of visibility Poor data with limited access The inability to truly collaborate enterprise-wide throughout your extended value chain Choose the Right Remedy Product Lifecycle Management (PLM) solutions are uniquely designed to help companies solve these types challenges and their root causes. However, PLM solutions can vary widely in terms of configurability, functionality, time-to-value, etc. Business leaders should evaluate PLM solution in terms of their own business drivers and long-term vision to determine the right fit. Many of these solutions are point solutions that can help you cure only one or two business pains in the short term. Others have been designed to serve other industries with different needs. Then there are those solutions that demo well but are owned by companies that are either unable or unwilling to continuously improve their solution to stay abreast of the ever changing needs of the CP industry to grow through innovation. What the Right PLM Solution Should Do for You Based on more than twenty years working in the CP industry, I recommend investing in a single solution that can help you solve all of the issues associated with the science of innovation in a totally integrated fashion. By integration I mean the (1) integration of the all of the processes associated with the development, maintenance and delivery of your product data, and (2) the integration, or harmonization of this product data with other downstream sources, like ERP, product catalogues and the GS1 Global Data Synchronization Network (or GDSN, which is now a CP industry requirement for doing business with most retailers). The right PLM solution should help you: Increase Revenue. A best practice PLM solution should help a company grow its revenues by consolidating product development cycle-time and helping companies get new and improved products to market sooner. PLM should also eliminate many of the root causes for a product being returned, refused and/or reclaimed (which takes away from top-line growth) by creating an enterprise-wide, collaborative, workflow-driven environment. Reduce Costs. A strong PLM solution should help shave many unnecessary costs that companies typically take for granted. Rationalizing SKU’s, components (ingredients and packaging) and suppliers is a major opportunity at most companies that PLM should help address. A natural outcome of this rationalization is lower direct material spend and a reduction of inventory. Another cost cutting opportunity comes with PLM when it helps companies avoid certain costs associated with process inefficiencies that lead to scrap, rework, excess and obsolete inventory, poor end of life administration, higher cost of quality and regulatory and increased expediting. Mitigate Risk. Risks are the hardest to quantify but can be the most costly to a company. Food safety, recalls, line shutdowns, customer dissatisfaction and, worst of all, the potential tarnishing of your brands are a few of the debilitating risks that CP companies deal with on a daily basis. These risks are so uniquely severe that they require an enterprise PLM solution specifically designed for the CP industry that safeguards product information and processes while still allowing the art of innovation to flourish. Many CP companies have already created a winning advantage by leveraging a single, best practice PLM solution to establish an enterprise-wide, systematic approach to innovation. Oracle’s Answer for the Consumer Products Industry Oracle is dedicated to solving the growth and innovation challenges facing the CP industry. Oracle’s Agile Product Lifecycle Management for Process solution was originally developed with and for CP companies and is driven by a specialized development staff solely focused on maintaining and continuously improving the solution per the latest industry requirements. Agile PLM for Process helps CP companies handle all of the processes associated with managing the science of the innovation process, including: specification management, new product development/project and portfolio management, formulation optimization, supplier management, and quality and regulatory compliance to name a few. And as I mentioned earlier, integration is absolutely critical. Many Oracle CP customers, both with Oracle ERP systems and non-Oracle ERP systems, report benefits from Oracle’s Agile PLM for Process. In future articles we will explain in greater detail how both existing Oracle customers (like Gallo, Smuckers, Land-O-Lakes and Starbucks) and new Oracle customers (like ConAgra, Tyson, McDonalds and Heinz) have all realized the benefits of Agile PLM for Process and its integration to their ERP systems. More to Come Stay tuned for more articles in our blog series “The Business of Winning Innovation.” While we will also feature articles focused on other industries, look forward to more on how Agile PLM for Process addresses innovation challenges facing the CP industry. Additional topics include: Innovation Data Management (IDM), New Product Development (NPD), Product Quality Management (PQM), Menu Management,Private Label Management, and more! . Watch this video for more info about Agile PLM for Process

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Fast programmatic compare of "timetable" data

- by Brendan Green

Consider train timetable data, where each service (or "run") has a data structure as such: public class TimeTable { public int Id {get;set;} public List<Run> Runs {get;set;} } public class Run { public List<Stop> Stops {get;set;} public int RunId {get;set;} } public class Stop { public int StationId {get;set;} public TimeSpan? StopTime {get;set;} public bool IsStop {get;set;} } We have a list of runs that operate against a particular line (the TimeTable class). Further, whilst we have a set collection of stations that are on a line, not all runs stop at all stations (that is, IsStop would be false, and StopTime would be null). Now, imagine that we have received the initial timetable, processed it, and loaded it into the above data structure. Once the initial load is complete, it is persisted into a database - the data structure is used only to load the timetable from its source and to persist it to the database. We are now receiving an updated timetable. The updated timetable may or may not have any changes to it - we don't know and are not told whether any changes are present. What I would like to do is perform a compare for each run in an efficient manner. I don't want to simply replace each run. Instead, I want to have a background task that runs periodically that downloads the updated timetable dataset, and then compares it to the current timetable. If differences are found, some action (not relevant to the question) will take place. I was initially thinking of some sort of checksum process, where I could, for example, load both runs (that is, the one from the new timetable received and the one that has been persisted to the database) into the data structure and then add up all the hour components of the StopTime, and all the minute components of the StopTime and compare the results (i.e. both the sum of Hours and sum of Minutes would be the same, and differences introduced if a stop time is changed, a stop deleted or a new stop added). Would that be a valid way to check for differences, or is there a better way to approach this problem? I can see a problem that, for example, one stop is changed to be 2 minutes earlier, and another changed to be 2 minutes later would have a net zero change. Or am I over thinking this, and would it just be simpler to brute check all stops to ensure that The updated run stops at the same stations; and Each stop is at the same time

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Don Knuth and MMIXAL vs. Chuck Moore and Forth -- Algorithms and Ideal Machines -- was there cross-pollination / influence in their ideas / work?

- by AKE

Question: To what extent is it known (or believed) that Chuck Moore and Don Knuth had influence on each other's thoughts on ideal machines, or their work on algorithms? I'm interested in citations, interviews, articles, links, or any other sort of evidence. It could also be evidence of the form of A and B here suggest that Moore might have borrowed or influenced C and D from Knuth here, or vice versa. (Opinions are of course welcome, but references / links would be better!) Context: Until fairly recently, I have been primarily familiar with Knuth's work on algorithms and computing models, mostly through TAOCP but also through his interviews and other writings. However, the more I have been using Forth, the more I am struck by both the power of a stack-based machine model, and the way in which the spareness of the model makes fundamental algorithmic improvements more readily apparent. A lot of what Knuth has done in fundamental analysis of algorithms has, it seems to me, a very similar flavour, and I can easily imagine that in a parallel universe, Knuth might perhaps have chosen Forth as his computing model. That's the software / algorithms / programming side of things. When it comes to "ideal computing machines", Knuth in the 70s came up with the MIX computer model, and then, collaborating with designers of state-of-the-art RISC chips through the 90s, updated this with the modern MMIX model and its attendant assembly language MMIXAL. Meanwhile, Moore, having been using and refining Forth as a language, but using it on top of whatever processor happened to be in the computer he was programming, began to imagine a world in which the efficiency and value of stack-based programming were reflected in hardware. So he went on in the 80s to develop his own stack-based hardware chips, defining the term MISC (Minimal Instruction Set Computers) along the way, and ending up eventually with the first Forth chip, the MuP21. Both are brilliant men with keen insight into the art of programming and algorithms, and both work at the intersection between algorithms, programs, and bare metal hardware (i.e. hardware without the clutter of operating systems). Which leads me to the headlined question... Question:To what extent is it known (or believed) that Chuck Moore and Don Knuth had influence on each other's thoughts on ideal machines, or their work on algorithms?

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How to store Role Based Access rights in web application?

- by JonH

Currently working on a web based CRM type system that deals with various Modules such as Companies, Contacts, Projects, Sub Projects, etc. A typical CRM type system (asp.net web form, C#, SQL Server backend). We plan to implement role based security so that basically a user can have one or more roles. Roles would be broken down by first the module type such as: -Company -Contact And then by the actions for that module for instance each module would end up with a table such as this: Role1 Example: Module Create Edit Delete View Company Yes Owner Only No Yes Contact Yes Yes Yes Yes In the above case Role1 has two module types (Company, and Contact). For company, the person assigned to this role can create companies, can view companies, can only edit records he/she created and cannot delete. For this same role for the module contact this user can create contacts, edit contacts, delete contacts, and view contacts (full rights basically). I am wondering is it best upon coming into the system to session the user's role with something like a: List<Role> roles; Where the Role class would have some sort of List<Module> modules; (can contain Company, Contact, etc.).? Something to the effect of: class Role{ string name; string desc; List<Module> modules; } And the module action class would have a set of actions (Create, Edit, Delete, etc.) for each module: class ModuleActions{ List<Action> actions; } And the action has a value of whether the user can perform the right: class Action{ string right; } Just a rough idea, I know the action could be an enum and the ModuleAction can probably be eliminated with a List<x, y>. My main question is what would be the best way to store this information in this type of application: Should I store it in the User Session state (I have a session class where I manage things related to the user). I generally load this during the initial loading of the application (global.asax). I can simply tack onto this session. Or should this be loaded at the page load event of each module (page load of company etc..). I eventually need to be able to hide / unhide various buttons / divs based on the user's role and that is what got me thinking to load this via session. Any examples or points would be great.

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Source of (programmer) inefficiency

- by Daniel

I am interested to gain a better insight about the possible reasons of personal inefficiency as programmers (and only in programming) due to – simply - our own errors (because we are humans – well, almost all of us). I am not interested in how much we are productive or in how many adjustements the customer asks for when the work is done, but where and how each of us spend that part of its time in tasks that are unproductive and there is no one to blame except ourselves. Excluding ego - feeding and / or self – gratification, what I am trying to get (for all of us) is: what are the common issues eating our time; insight on reasons for that issues; identify simple way for us, personally (not delegating actions to other or our organizations), to correct our own problems. Please, do not think in academic terms but aim at the opportunity to compare our daily experiences and understand what are and how we try to fix our personal deficiencies. If you are interested to respond to this post, please: integrate the list if you see something important (or obvious) missing; highlight or name honestly your first issue tellng the way you try to address and solve your issue acting on yourself and yourself only in a sort of "continuous quality improving" My criteria for accepting the answer is: choose the best solution (feasibility and utility) to fix one (or more) of the problems of the list. Of course, selecting an error is not a vote on our skills: maybe we are hyper professional programmers and we lose ten minutes only every year or we are terribly inefficient, losing a couple of days a week: reasons for inefficiency could be really the same - but in a different scale. A possible list: Plain error in the names (variables, functions). Inability to see the obvious in your code. Misreading. Lack of concentration. Trying to use a technology you have not mastered. Errors with data types. Time required to understand your previous code or your documentation. Trying to do something more than requested because you enjoy it Using solutions more complicated than required because you enjoy it. Plain logical errors. Errors due to your fault in communications. Distraction My first personal issue: "Trying to use a technology you do not master." I have to use daily several technologies and I often need to spend significant time correcting code because my assumptions were plainly wrong. Reasons for this: production needs put high pressure and make difficult to find the time to learn. I try to address this reading technical books - as many as I can - even if this actually consumes a lot of time.

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Silverlight Cream for June 15, 2010 - 2 -- #883

- by Dave Campbell

In this Issue: Vibor Cipan, Chris Klug, Pete Brown, Kirupa, and Xianzhong Zhu. Shoutouts (thought I gave up on them, didn't you?): Jesse Liberty has the companion video to his WP7 OData post up: New Video: Master/Detail in WinPhone 7 with oData Michael Scherotter who made the first Ball Watch SL1 app back in the day, has a Virtual Event: Creating an Entry for the BALL Watch Silverlight Contest... sounds like the thing to do if you want in on this :) Even if you don't speak Portuguese, you can check this out: MSN Brazil Uses Silverlight to Showcase the 2010 FIFA World Cup South Africa Erik Mork and crew have their latest up: This Week in Silverlight – Teched and Quizes Michael Klucher has a post up to give you some relief if you're having Trouble Installing the Windows Phone Developer Tools Portuguese above and now French... Jeremy Alles has a post up about [WP7] Windows Phone 7 challenge for french readers ! Just a note, not that it makes any difference, but Adam Kinney turned @SilverlightNews over to me today. I am the only one that has ever posted on it, but still having it all to myself feels special :) From SilverlightCream.com: Silverlight 4 tutorial: HOW TO use PathListBox and Sample Data Crank up that new version of Blend and follow along with Vibor Cipan's PathListBox tutorial ... oh, and sample data too. Cool INotifyPropertyChanged implementation Chris Klug shows off some INotifyPropertyChange goodness he is not implementing, and credits a blog by Manuel Felicio for some inspiration. Check out that post as well... I've tagged his blog... I needed *another* one :) Silverlight Tip: Using LINQ to Select the Largest Available Webcam Resolution With no Silverlight Tip of the Day today, Pete Brown stepped up with this tip for finding the largest available webcam resolution using LINQ ... and read the comment from Rene as well. Creating a Master-Detail UI in Blend Kirupa has a very nice Master/Detail UI post up with backrounder info and the code for the project. There's a running example in the post for you to get an idea what you're learning. Get started with Farseer Physics 2.1.3 in Silverlight 3 Xianzhong Zhu has a Silverlight 3 tutorial up for Farseer Physics 2.1.3 ... might track for Silverlight 4, but hey, WP7 is kinda/sort Silverlight 3, right? ... lots of code and external links. Stay in the 'Light! Twitter SilverlightNews | Twitter WynApse | WynApse.com | Tagged Posts | SilverlightCream Join me @ SilverlightCream | Phoenix Silverlight User Group Technorati Tags: Silverlight Silverlight 3 Silverlight 4 Windows Phone MIX10

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Canonicalization of single, small pages like reviews or product categories [SEO]

- by Valorized

In general I pretty much like the idea of canonicalization. And in most cases, Google explains possible procedures in a clear way. For example: If I have duplicates because of parameters (eg: &sort=desc) it's clear to use the canonical for the site, provided the within the head-tag. However I'm wondering how to handle "small - no to say thin content - sites". What's my definition of a small site? An Example: On one of my main sites, we use a directory based url-structure. Let's see: example.com/ (root) example.com/category-abc/ example.com/category-abc/produkt-xy/ Moreover we provide on page, that includes all products example.com/all-categories/ (lists all products the same way as in the categories) In case of reviews, we use a similar structure: example.com/reviews/product-xy/ shows all review for one certain product example.com/reviews/product-xy/abc-your-product-is-great/ shows one certain review example.com/reviews/ shows all reviews for all products (latest first) Let's make it even more complicated: On every product site, there are the latest 2 reviews at the end of the page. So you see, a lot of potential duplicates. Q1: Should I create canonicals for a: example.com/category-abc/ to example.com/all-categories/ b: example.com/reviews/product-xy/abc-your-product-is-great/ to example.com/reviews/product-xy/ or to example.com/review/ or none of them? Q2: Can I link the collection of categories (all-categories/) and collection of all reviews (reviews/ and reviews/product-xy/) to the single category respectively to the single review. Example: example.com/reviews/ includes - let's say - 100 reviews. Can I somehow use a markup that tells search engines: "Hey, wait, you are now looking at a collection of 100 reviews - do not index this collection, you should rather prefer indexing every single review as a single page!". In HTML it might be something like that (which - of course - does not work, it's only to show you what I mean): <div class="review" rel="canonical" href="http://example.com/reviews/product-xz/abc-your-product-is-great/">HERE GOES THE REVIEW</div> Reason: I don't think it is a great user experience if the user searches for "your product is great" and lands on example.com/reviews/ instead of example.com/reviews/product-xy/abc-your-product-is-great/. On the first site, he will have to search and might stop because of frustration. The second result, however, might lead to a conversion. The same applies for categories. If the user is searching for category-Z, he might land on the all-categories page and he has to scroll down to the (last) category, to find what he searched for (Z). So what's best practice? What should I do? Thank you for your help!

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Video stutter when using external drive

- by psion

When using boxee to play video files off of an external western digital 1TB drive formatted NTFS, I notice a slight stutter in the video every 5-10 seconds. When using mplayer, it doesn't stutter as often, but it still stutters occasionally. If I play the video off of the local sata drive, it plays fine even in boxee. I use this computer as my HTPC and I just switched from windows to linux on it. In windows, I never had any sort of stutter playing movies from the drive. I am using the latest intel graphics drivers (for the intel GMA 950) root@eee-htpc:/home/htpc# grep wd /etc/mtab /dev/sdb1 /mnt/wd2 fuseblk rw,nosuid,nodev,allow_other,blksize=512 0 0 I notice that despite trying to use ntfs or ntfs-3g, ubuntu uses ntfs-fuse which I've heard is slower. /dev/sdb1: Timing buffered disk reads: 80 MB in 3.07 seconds = 26.08 MB/sec root@eee-htpc:/mnt/wd2# dd if=/dev/zero of=./120mb bs=1024 count=120000 root@eee-htpc:/mnt/wd2# time mv ./120mb /home/htpc real 0m2.095s user 0m0.016s sys 0m0.736s Even though fuse has a reputation for being slow, it should easily be fast enough for playing standard definition video files. So why the video stutter? edit: The issue seems to be overhead cpu usage from either playing off of a usb device or ntfs/fuse. Watching CPU usage with top, local files use 10-40% CPU. Watching the same video on the external formatted ntfs, it spikes to 170% (over 100% because of hyperthreading). To me it seems like it must be overhead from the fuse driver, though I don't know if it has more or less overhead than ntfs-3g. It's a EEEBox B202 that has an atom 270, so not exactly the most powerful out there. edit2: I believe the solution would be to use non-fuse drivers or different fuse drivers. so far I have not been able to. edit3: I've probably edited this more times than I should, but as an update I have upgraded ntfs drivers to ntfs-3g 2010.8.8 external FUSE 28 - Third Generation NTFS Driver using the following PPA - ppa:x3lectric/team-iquik-releases. When first opening a video file in boxee that's on ntfs there's still the same amount of lag. After a few minutes of video, the lag seems to go away and the cpu usage comes down to 10-40%. Every so often though, it begins to stutter again. Also, if I skip ahead/back in the file, it begins to stutter a lot.

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Working with Reporting Services Filters – Part 3: The TOP and BOTTOM Operators

- by smisner

Thus far in this series, I have described using the IN operator and the LIKE operator. Today, I’ll continue the series by reviewing the TOP and BOTTOM operators. Today, I happened to be working on an example of using the TOP N operator and was not successful on my first try because the behavior is just a bit different than we find when using an “equals” comparison as I described in my first post in this series. In my example, I wanted to display a list of the top 5 resellers in the United States for AdventureWorks, but I wanted it based on a filter. I started with a hard-coded filter like this: Expression Data Type Operator Value [ResellerSalesAmount] Float Top N 5 And received the following error: A filter value in the filter for tablix 'Tablix1' specifies a data type that is not supported by the 'TopN' operator. Verify that the data type for each filter value is Integer. Well, that puzzled me. Did I really have to convert ResellerSalesAmount to an integer to use the Top N operator? Just for kicks, I switched to the Top % operator like this: Expression Data Type Operator Value [ResellerSalesAmount] Float Top % 50 This time, I got exactly the results I expected – I had a total of 10 records in my dataset results, so 50% of that should yield 5 rows in my tablix. So thinking about the problem with Top N some more, I switched the Value to an expression, like this: Expression Data Type Operator Value [ResellerSalesAmount] Float Top N =5 And it worked! So the value for Top N or Top % must reflect a number to plug into the calculation, such as Top 5 or Top 50%, and the expression is the basis for determining what’s in that group. In other words, Reporting Services will sort the rows by the expression – ResellerSalesAmount in this case – in descending order, and then filter out everything except the topmost rows based on the operator you specify. The curious thing is that, if you’re going to hard-code the value, you must enter the value for Top N with an equal sign in front of the integer, but you can omit the equal sign when entering a hard-coded value for Top %. This experience is why working with Reporting Services filters is not always intuitive! When you use a report parameter to set the value, you won’t have this problem. Just be sure that the data type of the report parameter is set to Integer. Jessica Moss has an example of using a Top N filter in a tablix which you can view here. Working with Bottom N and Bottom % works similarly. You just provide a number for N or for the percentage and Reporting Services works from the bottom up to determine which rows are kept and which are excluded.

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Internal Mutation of Persistent Data Structures

- by Greg Ros

To clarify, when I mean use the terms persistent and immutable on a data structure, I mean that: The state of the data structure remains unchanged for its lifetime. It always holds the same data, and the same operations always produce the same results. The data structure allows Add, Remove, and similar methods that return new objects of its kind, modified as instructed, that may or may not share some of the data of the original object. However, while a data structure may seem to the user as persistent, it may do other things under the hood. To be sure, all data structures are, internally, at least somewhere, based on mutable storage. If I were to base a persistent vector on an array, and copy it whenever Add is invoked, it would still be persistent, as long as I modify only locally created arrays. However, sometimes, you can greatly increase performance by mutating a data structure under the hood. In more, say, insidious, dangerous, and destructive ways. Ways that might leave the abstraction untouched, not letting the user know anything has changed about the data structure, but being critical in the implementation level. For example, let's say that we have a class called ArrayVector implemented using an array. Whenever you invoke Add, you get a ArrayVector build on top of a newly allocated array that has an additional item. A sequence of such updates will involve n array copies and allocations. Here is an illustration: However, let's say we implement a lazy mechanism that stores all sorts of updates -- such as Add, Set, and others in a queue. In this case, each update requires constant time (adding an item to a queue), and no array allocation is involved. When a user tries to get an item in the array, all the queued modifications are applied under the hood, requiring a single array allocation and copy (since we know exactly what data the final array will hold, and how big it will be). Future get operations will be performed on an empty cache, so they will take a single operation. But in order to implement this, we need to 'switch' or mutate the internal array to the new one, and empty the cache -- a very dangerous action. However, considering that in many circumstances (most updates are going to occur in sequence, after all), this can save a lot of time and memory, it might be worth it -- you will need to ensure exclusive access to the internal state, of course. This isn't a question about the efficacy of such a data structure. It's a more general question. Is it ever acceptable to mutate the internal state of a supposedly persistent or immutable object in destructive and dangerous ways? Does performance justify it? Would you still be able to call it immutable? Oh, and could you implement this sort of laziness without mutating the data structure in the specified fashion?

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