Search Results

Search found 22653 results on 907 pages for 'robert may'.

Page 401/907 | < Previous Page | 397 398 399 400 401 402 403 404 405 406 407 408  | Next Page >

  • Generating a record of the full(-ish) package management state

    - by intuited
    I'm about to make some system changes and I'd like to have a record of my current happy system state. Is there a convenient way to create a record of this? I'd like to keep track of info like currently installed packages and their versions which packages are pinned at what version which source (as in /etc/apt/sources.list) they were installed from whether they were installed directly or automatically installed as a dependency of a different package "unknown unknowns": ie stuff that I don't know that I should be keeping track of but which may be important when trying to figure out why something doesn't work In short, I'd like to keep as much of the aptitude database as possible. What's the best way to do this? It would be nice if the resulting records were easily readable, though this is not really essential. It would be extra nice if it were readily versionable through an SCM tool like git. There is a superuser question that partially answers this, but it only provides the list of currently installed packages.

    Read the article

  • Generating a record of the full(-ish) package management state

    - by intuited
    I'm about to make some system changes and I'd like to have a record of my current happy system state. Is there a convenient way to create a record of this? I'd like to keep track of info like currently installed packages and their versions which packages are pinned at what version which source (as in /etc/apt/sources.list) they were installed from whether they were installed directly or automatically installed as a dependency of a different package "unknown unknowns": ie stuff that I don't know that I should be keeping track of but which may be important when trying to figure out why something doesn't work In short, I'd like to keep as much of the aptitude database as possible. What's the best way to do this? It would be nice if the resulting records were easily readable, though this is not really essential. It would be extra nice if it were readily versionable through an SCM tool like git. There is a superuser question that partially answers this, but it only provides the list of currently installed packages.

    Read the article

  • Can't copy files with 'additional permissions' to ext4 drive -- files that have @ after permissions,

    - by 99miles
    I am copying files from Snow Leopard to a mounted ext4 share via Samba, that's on a Fedora machine. Some files cannot be copied, and give this error: The operation can’t be completed because you don’t have permission to access some of the items. I've noticed that the files that can't be copied have an @ at the end of their permissions whien I do 'ls -l' in the command line. For example, I can copy the second file but not the first: -rwxrwxrwx@ 1 miles staff 1448 May 14 22:55 test.txt -rw-r--r-- 1 miles staff 136 Apr 5 17:06 image.psd.zip From what I've found, the @ means the file has 'additional properties'. Does anyone know how I can resolve this issue so I can copy the files to the fileshare?? Thanks!

    Read the article

  • Should a developer create test cases and then run through test cases

    - by Eben Roux
    I work for a company where the development manager expects a developer to create test cases before writing any code. These test cases have to then be maintained by the developers. Every-so-often a developer will be expected to run through the test cases. From this you should be able to gather that the company in question is rather small and there are no testers. Coming from a Software Architect position and having to write / execute test cases wearing my 'tester' hat is somewhat of a shock to the system. I do it anyway but it does seem to be a rather expensive exercise :) EDIT: I seem to need to elaborate here: I am not talking about unit-testing, TDD, etc. :) I am talking about that bit of testing a tester does. Once I have developed a system (with my unit tests / tdd / etc.) the software goes through a testing phase. Should a developer be that tester and developer those test cases? I think the misunderstanding may stem from the fact that developers, typically, are not involved with this type of testing and, therefore, assumed I am referring to that testing we do do: unit testing. But alas, no. I hope that clears it up.

    Read the article

  • Windows XP cannot execute binary file on Network Share

    - by angerman
    I'm having a Network Share provided by a Mac OS X Lion Server on a recent Mac Mini Server (CIFS / SMB); mounting the share in Windows (XP) is no problem, reading and writing neither. But when ever I try to execute an executable .exe, Windows complains that it's not a valid win32 executable. Copying the file from the network share to the desktop or some other local location, allows the file to be subsequently executed. Pointers to what the root cause of this problem may be are greatly appreciated.

    Read the article

  • Archiving to Tape

    - by Bruno
    This is not about backups, this is about archiving. For arguments sake lets say I have 2TB 7z file that I would like to archive to tape. I have 4 LTO-5 tapes ( 1.5TB each ). This may be a stupid question but what set up would I need that would allow me to drag and drop those files directly onto those 2 tapes and would automatically split the file accross 2 tapes like so: ------------------ | Copy 1 | | 1.5TB | ------------------ ------------------ | Copy 1 | | 0.5TB | ------------------ ------------------ | Copy 2 | | 1.5TB | ------------------ ------------------ | Copy 2 | | 0.5TB | ------------------ I just want to be able to specify which files go on which tapes as oppose to backups where the tapes just rotate. Thanks.

    Read the article

  • Adding an Admin user to an ASP.NET MVC 4 application using a single drop-in file

    - by Jon Galloway
    I'm working on an ASP.NET MVC 4 tutorial and wanted to set it up so just dropping a file in App_Start would create a user named "Owner" and assign them to the "Administrator" role (more explanation at the end if you're interested). There are reasons why this wouldn't fit into most application scenarios: It's not efficient, as it checks for (and creates, if necessary) the user every time the app starts up The username, password, and role name are hardcoded in the app (although they could be pulled from config) Automatically creating an administrative account in code (without user interaction) could lead to obvious security issues if the user isn't informed However, with some modifications it might be more broadly useful - e.g. creating a test user with limited privileges, ensuring a required account isn't accidentally deleted, or - as in my case - setting up an account for demonstration or tutorial purposes. Challenge #1: Running on startup without requiring the user to install or configure anything I wanted to see if this could be done just by having the user drop a file into the App_Start folder and go. No copying code into Global.asax.cs, no installing addition NuGet packages, etc. That may not be the best approach - perhaps a NuGet package with a dependency on WebActivator would be better - but I wanted to see if this was possible and see if it offered the best experience. Fortunately ASP.NET 4 and later provide a PreApplicationStartMethod attribute which allows you to register a method which will run when the application starts up. You drop this attribute in your application and give it two parameters: a method name and the type that contains it. I created a static class named PreApplicationTasks with a static method named, then dropped this attribute in it: [assembly: PreApplicationStartMethod(typeof(PreApplicationTasks), "Initializer")] That's it. One small gotcha: the namespace can be a problem with assembly attributes. I decided my class didn't need a namespace. Challenge #2: Only one PreApplicationStartMethod per assembly In .NET 4, the PreApplicationStartMethod is marked as AllMultiple=false, so you can only have one PreApplicationStartMethod per assembly. This was fixed in .NET 4.5, as noted by Jon Skeet, so you can have as many PreApplicationStartMethods as you want (allowing you to keep your users waiting for the application to start indefinitely!). The WebActivator NuGet package solves the multiple instance problem if you're in .NET 4 - it registers as a PreApplicationStartMethod, then calls any methods you've indicated using [assembly: WebActivator.PreApplicationStartMethod(type, method)]. David Ebbo blogged about that here:  Light up your NuGets with startup code and WebActivator. In my scenario (bootstrapping a beginner level tutorial) I decided not to worry about this and stick with PreApplicationStartMethod. Challenge #3: PreApplicationStartMethod kicks in before configuration has been read This is by design, as Phil explains. It allows you to make changes that need to happen very early in the pipeline, well before Application_Start. That's fine in some cases, but it caused me problems when trying to add users, since the Membership Provider configuration hadn't yet been read - I got an exception stating that "Default Membership Provider could not be found." The solution here is to run code that requires configuration in a PostApplicationStart method. But how to do that? Challenge #4: Getting PostApplicationStartMethod without requiring WebActivator The WebActivator NuGet package, among other things, provides a PostApplicationStartMethod attribute. That's generally how I'd recommend running code that needs to happen after Application_Start: [assembly: WebActivator.PostApplicationStartMethod(typeof(TestLibrary.MyStartupCode), "CallMeAfterAppStart")] This works well, but I wanted to see if this would be possible without WebActivator. Hmm. Well, wait a minute - WebActivator works in .NET 4, so clearly it's registering and calling PostApplicationStartup tasks somehow. Off to the source code! Sure enough, there's even a handy comment in ActivationManager.cs which shows where PostApplicationStartup tasks are being registered: public static void Run() { if (!_hasInited) { RunPreStartMethods(); // Register our module to handle any Post Start methods. But outside of ASP.NET, just run them now if (HostingEnvironment.IsHosted) { Microsoft.Web.Infrastructure.DynamicModuleHelper.DynamicModuleUtility.RegisterModule(typeof(StartMethodCallingModule)); } else { RunPostStartMethods(); } _hasInited = true; } } Excellent. Hey, that DynamicModuleUtility seems familiar... Sure enough, K. Scott Allen mentioned it on his blog last year. This is really slick - a PreApplicationStartMethod can register a new HttpModule in code. Modules are run right after application startup, so that's a perfect time to do any startup stuff that requires configuration to be read. As K. Scott says, it's this easy: using System; using System.Web; using Microsoft.Web.Infrastructure.DynamicModuleHelper; [assembly:PreApplicationStartMethod(typeof(MyAppStart), "Start")] public class CoolModule : IHttpModule { // implementation not important // imagine something cool here } public static class MyAppStart { public static void Start() { DynamicModuleUtility.RegisterModule(typeof(CoolModule)); } } Challenge #5: Cooperating with SimpleMembership The ASP.NET MVC Internet template includes SimpleMembership. SimpleMembership is a big improvement over traditional ASP.NET Membership. For one thing, rather than forcing a database schema, it can work with your database schema. In the MVC 4 Internet template case, it uses Entity Framework Code First to define the user model. SimpleMembership bootstrap includes a call to InitializeDatabaseConnection, and I want to play nice with that. There's a new [InitializeSimpleMembership] attribute on the AccountController, which calls \Filters\InitializeSimpleMembershipAttribute.cs::OnActionExecuting(). That comment in that method that says "Ensure ASP.NET Simple Membership is initialized only once per app start" which sounds like good advice. I figured the best thing would be to call that directly: new Mvc4SampleApplication.Filters.InitializeSimpleMembershipAttribute().OnActionExecuting(null); I'm not 100% happy with this - in fact, it's my least favorite part of this solution. There are two problems - first, directly calling a method on a filter, while legal, seems odd. Worse, though, the Filter lives in the application's namespace, which means that this code no longer works well as a generic drop-in. The simplest workaround would be to duplicate the relevant SimpleMembership initialization code into my startup code, but I'd rather not. I'm interested in your suggestions here. Challenge #6: Module Init methods are called more than once When debugging, I noticed (and remembered) that the Init method may be called more than once per page request - it's run once per instance in the app pool, and an individual page request can cause multiple resource requests to the server. While SimpleMembership does have internal checks to prevent duplicate user or role entries, I'd rather not cause or handle those exceptions. So here's the standard single-use lock in the Module's init method: void IHttpModule.Init(HttpApplication context) { lock (lockObject) { if (!initialized) { //Do stuff } initialized = true; } } Putting it all together With all of that out of the way, here's the code I came up with: using Mvc4SampleApplication.Filters; using System.Web; using System.Web.Security; using WebMatrix.WebData; [assembly: PreApplicationStartMethod(typeof(PreApplicationTasks), "Initializer")] public static class PreApplicationTasks { public static void Initializer() { Microsoft.Web.Infrastructure.DynamicModuleHelper.DynamicModuleUtility .RegisterModule(typeof(UserInitializationModule)); } } public class UserInitializationModule : IHttpModule { private static bool initialized; private static object lockObject = new object(); private const string _username = "Owner"; private const string _password = "p@ssword123"; private const string _role = "Administrator"; void IHttpModule.Init(HttpApplication context) { lock (lockObject) { if (!initialized) { new InitializeSimpleMembershipAttribute().OnActionExecuting(null); if (!WebSecurity.UserExists(_username)) WebSecurity.CreateUserAndAccount(_username, _password); if (!Roles.RoleExists(_role)) Roles.CreateRole(_role); if (!Roles.IsUserInRole(_username, _role)) Roles.AddUserToRole(_username, _role); } initialized = true; } } void IHttpModule.Dispose() { } } The Verdict: Is this a good thing? Maybe. I think you'll agree that the journey was undoubtedly worthwhile, as it took us through some of the finer points of hooking into application startup, integrating with membership, and understanding why the WebActivator NuGet package is so useful Will I use this in the tutorial? I'm leaning towards no - I think a NuGet package with a dependency on WebActivator might work better: It's a little more clear what's going on Installing a NuGet package might be a little less error prone than copying a file A novice user could uninstall the package when complete It's a good introduction to NuGet, which is a good thing for beginners to see This code either requires either duplicating a little code from that filter or modifying the file to use the namespace Honestly I'm undecided at this point, but I'm glad that I can weigh the options. If you're interested: Why are you doing this? I'm updating the MVC Music Store tutorial to ASP.NET MVC 4, taking advantage of a lot of new ASP.NET MVC 4 features and trying to simplify areas that are giving people trouble. One change that addresses both needs us using the new OAuth support for membership as much as possible - it's a great new feature from an application perspective, and we get a fair amount of beginners struggling with setting up membership on a variety of database and development setups, which is a distraction from the focus of the tutorial - learning ASP.NET MVC. Side note: Thanks to some great help from Rick Anderson, we had a draft of the tutorial that was looking pretty good earlier this summer, but there were enough changes in ASP.NET MVC 4 all the way up to RTM that there's still some work to be done. It's high priority and should be out very soon. The one issue I ran into with OAuth is that we still need an Administrative user who can edit the store's inventory. I thought about a number of solutions for that - making the first user to register the admin, or the first user to use the username "Administrator" is assigned to the Administrator role - but they both ended up requiring extra code; also, I worried that people would use that code without understanding it or thinking about whether it was a good fit.

    Read the article

  • Performance Optimization &ndash; It Is Faster When You Can Measure It

    - by Alois Kraus
    Performance optimization in bigger systems is hard because the measured numbers can vary greatly depending on the measurement method of your choice. To measure execution timing of specific methods in your application you usually use Time Measurement Method Potential Pitfalls Stopwatch Most accurate method on recent processors. Internally it uses the RDTSC instruction. Since the counter is processor specific you can get greatly different values when your thread is scheduled to another core or the core goes into a power saving mode. But things do change luckily: Intel's Designer's vol3b, section 16.11.1 "16.11.1 Invariant TSC The time stamp counter in newer processors may support an enhancement, referred to as invariant TSC. Processor's support for invariant TSC is indicated by CPUID.80000007H:EDX[8]. The invariant TSC will run at a constant rate in all ACPI P-, C-. and T-states. This is the architectural behavior moving forward. On processors with invariant TSC support, the OS may use the TSC for wall clock timer services (instead of ACPI or HPET timers). TSC reads are much more efficient and do not incur the overhead associated with a ring transition or access to a platform resource." DateTime.Now Good but it has only a resolution of 16ms which can be not enough if you want more accuracy.   Reporting Method Potential Pitfalls Console.WriteLine Ok if not called too often. Debug.Print Are you really measuring performance with Debug Builds? Shame on you. Trace.WriteLine Better but you need to plug in some good output listener like a trace file. But be aware that the first time you call this method it will read your app.config and deserialize your system.diagnostics section which does also take time.   In general it is a good idea to use some tracing library which does measure the timing for you and you only need to decorate some methods with tracing so you can later verify if something has changed for the better or worse. In my previous article I did compare measuring performance with quantum mechanics. This analogy does work surprising well. When you measure a quantum system there is a lower limit how accurately you can measure something. The Heisenberg uncertainty relation does tell us that you cannot measure of a quantum system the impulse and location of a particle at the same time with infinite accuracy. For programmers the two variables are execution time and memory allocations. If you try to measure the timings of all methods in your application you will need to store them somewhere. The fastest storage space besides the CPU cache is the memory. But if your timing values do consume all available memory there is no memory left for the actual application to run. On the other hand if you try to record all memory allocations of your application you will also need to store the data somewhere. This will cost you memory and execution time. These constraints are always there and regardless how good the marketing of tool vendors for performance and memory profilers are: Any measurement will disturb the system in a non predictable way. Commercial tool vendors will tell you they do calculate this overhead and subtract it from the measured values to give you the most accurate values but in reality it is not entirely true. After falling into the trap to trust the profiler timings several times I have got into the habit to Measure with a profiler to get an idea where potential bottlenecks are. Measure again with tracing only the specific methods to check if this method is really worth optimizing. Optimize it Measure again. Be surprised that your optimization has made things worse. Think harder Implement something that really works. Measure again Finished! - Or look for the next bottleneck. Recently I have looked into issues with serialization performance. For serialization DataContractSerializer was used and I was not sure if XML is really the most optimal wire format. After looking around I have found protobuf-net which uses Googles Protocol Buffer format which is a compact binary serialization format. What is good for Google should be good for us. A small sample app to check out performance was a matter of minutes: using ProtoBuf; using System; using System.Diagnostics; using System.IO; using System.Reflection; using System.Runtime.Serialization; [DataContract, Serializable] class Data { [DataMember(Order=1)] public int IntValue { get; set; } [DataMember(Order = 2)] public string StringValue { get; set; } [DataMember(Order = 3)] public bool IsActivated { get; set; } [DataMember(Order = 4)] public BindingFlags Flags { get; set; } } class Program { static MemoryStream _Stream = new MemoryStream(); static MemoryStream Stream { get { _Stream.Position = 0; _Stream.SetLength(0); return _Stream; } } static void Main(string[] args) { DataContractSerializer ser = new DataContractSerializer(typeof(Data)); Data data = new Data { IntValue = 100, IsActivated = true, StringValue = "Hi this is a small string value to check if serialization does work as expected" }; var sw = Stopwatch.StartNew(); int Runs = 1000 * 1000; for (int i = 0; i < Runs; i++) { //ser.WriteObject(Stream, data); Serializer.Serialize<Data>(Stream, data); } sw.Stop(); Console.WriteLine("Did take {0:N0}ms for {1:N0} objects", sw.Elapsed.TotalMilliseconds, Runs); Console.ReadLine(); } } The results are indeed promising: Serializer Time in ms N objects protobuf-net   807 1000000 DataContract 4402 1000000 Nearly a factor 5 faster and a much more compact wire format. Lets use it! After switching over to protbuf-net the transfered wire data has dropped by a factor two (good) and the performance has worsened by nearly a factor two. How is that possible? We have measured it? Protobuf-net is much faster! As it turns out protobuf-net is faster but it has a cost: For the first time a type is de/serialized it does use some very smart code-gen which does not come for free. Lets try to measure this one by setting of our performance test app the Runs value not to one million but to 1. Serializer Time in ms N objects protobuf-net 85 1 DataContract 24 1 The code-gen overhead is significant and can take up to 200ms for more complex types. The break even point where the code-gen cost is amortized by its faster serialization performance is (assuming small objects) somewhere between 20.000-40.000 serialized objects. As it turned out my specific scenario involved about 100 types and 1000 serializations in total. That explains why the good old DataContractSerializer is not so easy to take out of business. The final approach I ended up was to reduce the number of types and to serialize primitive types via BinaryWriter directly which turned out to be a pretty good alternative. It sounded good until I measured again and found that my optimizations so far do not help much. After looking more deeper at the profiling data I did found that one of the 1000 calls did take 50% of the time. So how do I find out which call it was? Normal profilers do fail short at this discipline. A (totally undeserved) relatively unknown profiler is SpeedTrace which does unlike normal profilers create traces of your applications by instrumenting your IL code at runtime. This way you can look at the full call stack of the one slow serializer call to find out if this stack was something special. Unfortunately the call stack showed nothing special. But luckily I have my own tracing as well and I could see that the slow serializer call did happen during the serialization of a bool value. When you encounter after much analysis something unreasonable you cannot explain it then the chances are good that your thread was suspended by the garbage collector. If there is a problem with excessive GCs remains to be investigated but so far the serialization performance seems to be mostly ok.  When you do profile a complex system with many interconnected processes you can never be sure that the timings you just did measure are accurate at all. Some process might be hitting the disc slowing things down for all other processes for some seconds as well. There is a big difference between warm and cold startup. If you restart all processes you can basically forget the first run because of the OS disc cache, JIT and GCs make the measured timings very flexible. When you are in need of a random number generator you should measure cold startup times of a sufficiently complex system. After the first run you can try again getting different and much lower numbers. Now try again at least two times to get some feeling how stable the numbers are. Oh and try to do the same thing the next day. It might be that the bottleneck you found yesterday is gone today. Thanks to GC and other random stuff it can become pretty hard to find stuff worth optimizing if no big bottlenecks except bloatloads of code are left anymore. When I have found a spot worth optimizing I do make the code changes and do measure again to check if something has changed. If it has got slower and I am certain that my change should have made it faster I can blame the GC again. The thing is that if you optimize stuff and you allocate less objects the GC times will shift to some other location. If you are unlucky it will make your faster working code slower because you see now GCs at times where none were before. This is where the stuff does get really tricky. A safe escape hatch is to create a repro of the slow code in an isolated application so you can change things fast in a reliable manner. Then the normal profilers do also start working again. As Vance Morrison does point out it is much more complex to profile a system against the wall clock compared to optimize for CPU time. The reason is that for wall clock time analysis you need to understand how your system does work and which threads (if you have not one but perhaps 20) are causing a visible delay to the end user and which threads can wait a long time without affecting the user experience at all. Next time: Commercial profiler shootout.

    Read the article

  • July, the 31 Days of SQL Server DMO’s – Day 20 (sys.dm_tran_locks)

    - by Tamarick Hill
    The sys.dm_tran_locks DMV is used to return active lock resources on your server. Locking is a mechanism used by SQL Server to protect the integrity of data when you have multiple users that may potentially access the same data at the same time. Let’s run a query against this DMV so we can analyze the results. SELECT * FROM sys.dm_tran_locks As we can see, its a lot of lock information returned from this DMV. I will not go into detail about each of the columns returned, but I will touch on the ones that I feel are the most important. The first column in the output is the resource_type column which tells you the type of lock a particular row represents. It could be a PAGE lock, RID, OBJECT, DATABASE, or several other lock types. The resource_database_id represents the id of the database for a particular lock resource. The resource_lock_partition column represents the ID of a lock partition. When you have a table that is partitioned, locks can be escalated to the partition level before going to a table level lock. The request_mode column gives us information about the type of lock that is being requested. From the screenshots above we see RangeS-S locks which represent a share range lock and IS locks which represent Intent Shared locks. The request_status column displays whether the lock has been granted or whether the lock is waiting to be acquired. The request_session_id  shows the session_id that is requesting the lock. This DMV is the best place to go when you need to identify the exact locks that are being held or pending for individual requests. You might need this information when you are troubleshooting severe blocking or deadlocking problems on your server. For more information on this DMV, please see the below Books Online link: http://msdn.microsoft.com/en-us/library/ms190345.aspx Follow me on Twitter @PrimeTimeDBA

    Read the article

  • What is the best way to build a database from a MS Word document?

    - by Jayron Soares
    Please advise me on how to approach this problem: I have a sequential list of metadata in a document in MS Word. The basic idea is to create a Python algorithm to iterate over the information, retrieving just the name of the PROCESS, when is made a queue, from a database. Example metadata: Process: Process Walker (1965) Exact reference: Walker Process Equipment., Inc. v. Food Machinery Corp. Link: http://caselaw.lp.findlaw.com/scripts/getcase.pl?court=US&vol=382&invol= Type of procedure: Certiorari to the United States Court of Appeals for the Seventh Circuit. Parties: Walker Process Equipment, Inc. Sector: Systems is ... Start Date: October 12-13 Arguedas, 1965 Summary: Food Machinery Company has initiated a process to stop or slow the entry of competitors through the use of a patent obtained by fraud. The case concerned a patent on "knee action swing diffusers" used in aeration equipment for sewage treatment systems, and the question was whether "the maintenance and enforcement of a patent obtained by fraud before the patent office" may be a basis for antitrust punishment. Report of the evolution process: petitioner, in answer to respond... Importance: a) First case which established an analysis for the diagnosis of dispute… There are about 200 pages containing the information above. I have in mind the idea of implementing an algorithm in Python to be able to break this information sequence and try to store it in a web database (an open source application that I’m looking for) in order to allow for free consultations.

    Read the article

  • VLOOKUP in Excel, part 2: Using VLOOKUP without a database

    - by Mark Virtue
    In a recent article, we introduced the Excel function called VLOOKUP and explained how it could be used to retrieve information from a database into a cell in a local worksheet.  In that article we mentioned that there were two uses for VLOOKUP, and only one of them dealt with querying databases.  In this article, the second and final in the VLOOKUP series, we examine this other, lesser known use for the VLOOKUP function. If you haven’t already done so, please read the first VLOOKUP article – this article will assume that many of the concepts explained in that article are already known to the reader. When working with databases, VLOOKUP is passed a “unique identifier” that serves to identify which data record we wish to find in the database (e.g. a product code or customer ID).  This unique identifier must exist in the database, otherwise VLOOKUP returns us an error.  In this article, we will examine a way of using VLOOKUP where the identifier doesn’t need to exist in the database at all.  It’s almost as if VLOOKUP can adopt a “near enough is good enough” approach to returning the data we’re looking for.  In certain circumstances, this is exactly what we need. We will illustrate this article with a real-world example – that of calculating the commissions that are generated on a set of sales figures.  We will start with a very simple scenario, and then progressively make it more complex, until the only rational solution to the problem is to use VLOOKUP.  The initial scenario in our fictitious company works like this:  If a salesperson creates more than $30,000 worth of sales in a given year, the commission they earn on those sales is 30%.  Otherwise their commission is only 20%.  So far this is a pretty simple worksheet: To use this worksheet, the salesperson enters their sales figures in cell B1, and the formula in cell B2 calculates the correct commission rate they are entitled to receive, which is used in cell B3 to calculate the total commission that the salesperson is owed (which is a simple multiplication of B1 and B2). The cell B2 contains the only interesting part of this worksheet – the formula for deciding which commission rate to use: the one below the threshold of $30,000, or the one above the threshold.  This formula makes use of the Excel function called IF.  For those readers that are not familiar with IF, it works like this: IF(condition,value if true,value if false) Where the condition is an expression that evaluates to either true or false.  In the example above, the condition is the expression B1<B5, which can be read as “Is B1 less than B5?”, or, put another way, “Are the total sales less than the threshold”.  If the answer to this question is “yes” (true), then we use the value if true parameter of the function, namely B6 in this case – the commission rate if the sales total was below the threshold.  If the answer to the question is “no” (false), then we use the value if false parameter of the function, namely B7 in this case – the commission rate if the sales total was above the threshold. As you can see, using a sales total of $20,000 gives us a commission rate of 20% in cell B2.  If we enter a value of $40,000, we get a different commission rate: So our spreadsheet is working. Let’s make it more complex.  Let’s introduce a second threshold:  If the salesperson earns more than $40,000, then their commission rate increases to 40%: Easy enough to understand in the real world, but in cell B2 our formula is getting more complex.  If you look closely at the formula, you’ll see that the third parameter of the original IF function (the value if false) is now an entire IF function in its own right.  This is called a nested function (a function within a function).  It’s perfectly valid in Excel (it even works!), but it’s harder to read and understand. We’re not going to go into the nuts and bolts of how and why this works, nor will we examine the nuances of nested functions.  This is a tutorial on VLOOKUP, not on Excel in general. Anyway, it gets worse!  What about when we decide that if they earn more than $50,000 then they’re entitled to 50% commission, and if they earn more than $60,000 then they’re entitled to 60% commission? Now the formula in cell B2, while correct, has become virtually unreadable.  No-one should have to write formulae where the functions are nested four levels deep!  Surely there must be a simpler way? There certainly is.  VLOOKUP to the rescue! Let’s redesign the worksheet a bit.  We’ll keep all the same figures, but organize it in a new way, a more tabular way: Take a moment and verify for yourself that the new Rate Table works exactly the same as the series of thresholds above. Conceptually, what we’re about to do is use VLOOKUP to look up the salesperson’s sales total (from B1) in the rate table and return to us the corresponding commission rate.  Note that the salesperson may have indeed created sales that are not one of the five values in the rate table ($0, $30,000, $40,000, $50,000 or $60,000).  They may have created sales of $34,988.  It’s important to note that $34,988 does not appear in the rate table.  Let’s see if VLOOKUP can solve our problem anyway… We select cell B2 (the location we want to put our formula), and then insert the VLOOKUP function from the Formulas tab: The Function Arguments box for VLOOKUP appears.  We fill in the arguments (parameters) one by one, starting with the Lookup_value, which is, in this case, the sales total from cell B1.  We place the cursor in the Lookup_value field and then click once on cell B1: Next we need to specify to VLOOKUP what table to lookup this data in.  In this example, it’s the rate table, of course.  We place the cursor in the Table_array field, and then highlight the entire rate table – excluding the headings: Next we must specify which column in the table contains the information we want our formula to return to us.  In this case we want the commission rate, which is found in the second column in the table, so we therefore enter a 2 into the Col_index_num field: Finally we enter a value in the Range_lookup field. Important:  It is the use of this field that differentiates the two ways of using VLOOKUP.  To use VLOOKUP with a database, this final parameter, Range_lookup, must always be set to FALSE, but with this other use of VLOOKUP, we must either leave it blank or enter a value of TRUE.  When using VLOOKUP, it is vital that you make the correct choice for this final parameter. To be explicit, we will enter a value of true in the Range_lookup field.  It would also be fine to leave it blank, as this is the default value: We have completed all the parameters.  We now click the OK button, and Excel builds our VLOOKUP formula for us: If we experiment with a few different sales total amounts, we can satisfy ourselves that the formula is working. Conclusion In the “database” version of VLOOKUP, where the Range_lookup parameter is FALSE, the value passed in the first parameter (Lookup_value) must be present in the database.  In other words, we’re looking for an exact match. But in this other use of VLOOKUP, we are not necessarily looking for an exact match.  In this case, “near enough is good enough”.  But what do we mean by “near enough”?  Let’s use an example:  When searching for a commission rate on a sales total of $34,988, our VLOOKUP formula will return us a value of 30%, which is the correct answer.  Why did it choose the row in the table containing 30% ?  What, in fact, does “near enough” mean in this case?  Let’s be precise: When Range_lookup is set to TRUE (or omitted), VLOOKUP will look in column 1 and match the highest value that is not greater than the Lookup_value parameter. It’s also important to note that for this system to work, the table must be sorted in ascending order on column 1! If you would like to practice with VLOOKUP, the sample file illustrated in this article can be downloaded from here. Similar Articles Productive Geek Tips Using VLOOKUP in ExcelImport Microsoft Access Data Into ExcelImport an Access Database into ExcelCopy a Group of Cells in Excel 2007 to the Clipboard as an ImageShare Access Data with Excel in Office 2010 TouchFreeze Alternative in AutoHotkey The Icy Undertow Desktop Windows Home Server – Backup to LAN The Clear & Clean Desktop Use This Bookmarklet to Easily Get Albums Use AutoHotkey to Assign a Hotkey to a Specific Window Latest Software Reviews Tinyhacker Random Tips DVDFab 6 Revo Uninstaller Pro Registry Mechanic 9 for Windows PC Tools Internet Security Suite 2010 Quickly Schedule Meetings With NeedtoMeet Share Flickr Photos On Facebook Automatically Are You Blocked On Gtalk? Find out Discover Latest Android Apps On AppBrain The Ultimate Guide For YouTube Lovers Will it Blend? iPad Edition

    Read the article

  • WinXP How to Tunnel LPT over USB

    - by Michael Pruitt
    I have a windows program that accesses a device connected to a LPT (1-3) 25 pin port. The communication is bidirectional, and I suspected the control lines are also accessed directly. I would like to migrate the device to a machine that does not have a LPT port. I saw the dos2usb software, but that takes the output (from a DOS program) and 'prints' it formatted for a specific printer. I need a raw LPT connection, and a cable that provides access to all the control signals. I do have a USB to 36-pin Centronics that may have the extra signals. I use it with a vinyl cutter that doesn't like most of the USB dongles. It comes up as USB001. Would adding and sharing a generic printer, then mapping LPT1 to the share get me closer? Would that work for a parallel port scanner? My preferred solution is a USB cable with a driver that will map it to LPT1, LPT2, or LPT3.

    Read the article

  • Problem closing MDI child window in Terminal Services/Remote Desktop Connection 7.0

    - by Justin Love
    I have one user whose computer just got updated to the 7.0 Remote Desktop Connection. Concurrently, she has started having a problem closing the MDI child windows in an old FoxPro application running on the remote server. We have two different servers, both 2003, running the same application, one locally and one at a remote office. Only the remote office server is giving trouble. It works fine for me, even when logging into her TS account. No other users have complained. The other day the same user experienced an error message (path not found for a path showing a localization placeholder) starting the RDC, fixed by reboot. I suspect she may have had RDC running during the 7.0 upgrade.

    Read the article

  • How did I get here? My route to Android, iPhone, Windows Phone 7, and interest in Mobile Devices

    - by Wallym
    I get asked all the time how/why I got interested in mobile and jumped on this fairly early.  I tend to give half answers because it wasn't just one thing that took me to mobile, but a whole host of separate ivents culminating in a specific event where I wasdoing market research in May/June 2008.  Let me throw out the events and the facts about me: I tend to like new, different, cool stuff.  I jumped on .NET early on.  I jumped on Ajax early on.  I don't jump on every new technology that comes down the road, I'm probably the only person on the planet that doesn't "get" MVC, though I acknowledge that a lot of people do and it solves a number of problems in the default settings of ASP.NET WebForms. I remember buying an early Windows CE device. It was interesting, but dang, this stylus thing sucks. After I lost my third stylus, i just gave up.  I got my first mobile phone in early 1999.  Reception was crappy, but I could see the value in being mobile. In 1999, I worked on a manufacturing systems project.  One piece of the projects was a set of handheld devices on the shop floor.  While the UI was a crappy DOS based, yes I said DOS as in Disk Operating System Version 6.22, I could see that the wireless world was a direction I wanted to be in. In 2000, Microsoft released the first public alpha of .NET.  Very cool stuff indeed.  One piece of the puzzle was a set of mobile controls for ASP.NET.  I build numerous test apps as well as mobile version using these mobile controls.  Now, the mobile UIs of the time were based on WML, which was crap. I could real all the analysis of mobile and read all about growth rates.  Now, you have to realize that growth rates can be impressive when dealing with small numbers, but I knew it was a comer. In our first book, I got talked out of mobile because of the line from the publisher "Wally, mobile doesn't sell." Blackberry was the dominant device of the mid 2000s.  Its users were referred to as "Crackberry addicts."  Unfortunately, the mobile development experience for native apps was crap and the web experience was fairly rough as well, but if they could get the ecosystem started, other phones and better blackberryies would come out.  I finally jumped into using a blackberry. Sometime around 2006, I heard "Wally, mobile doesn't sell" again.  Now, anyone that knows me knows that someone saying something like this to me means I'll keep trying it. The phones of the mid 2000s were moving to be more graphical, but there were too many that had this idea that they had to use a stylus.  Stylus suck.  They get lost too easily. I worked on a project in 2007 and 2008 for a startup trying to answer the question of "What is there to do where I am at?"  For some reason, they wanted to be tied to PCs.  As it became obvious that they were having problems, their investor asked us to do some market research and to figure out what the marketplace did want.  One of the important things that I figured out was the we lived in a mobile world and if you had a mobile app, it need to be on a mobile device, not tied to a desktop/laptop/netbook device.  If there was any single event, this was it - I was doing some market research and sat and talked to people in a bar/restaurant in Atlanta called "The Grove" on Lavista.  The consensus of the people that I talked to was that they wanted their data where ever they were at, laptop, pc, mobile, whereever. In 2007, Apple released the iPhone.  Wow, what an impressive device, even with all the problems of a 1st generation device.  I bought an iPod Touch 1st generation to understand touch better, one of the best decisions I ever made. I decided in late 2008, to make a move into cloud, for a number of reasons.  I was working on an example app.  In April, 2009, one of my friends at Microsoft said "don't mention my name with this, but you need an iPhone front end for this app."  How do you get on the iPhone.  Well, there are a number of ways including: ObjectiveC.  Its hard to teach an old dog new tricks, and this dog knows .NET, not ObjectiveC. HTML, web, javascript optimized interface.  yeah, this is possible. PhoneGap.  Now, this is interesting, take an html interface and get it to run on the iPhone, Android, Blackberry, and other platforms.  I thought that this way made the most sense for me until......... MonoTouch.  In May/June 2009, Novell announced a way for .NET/c# developers to write apps for the iPhone.  This is the way that made the most sense to me. Titanium by Appcelerator.  This is similar in concept to PhoneGap.  I haven't played with this much but do want to learn more about it. In July, 2009, I emailed one of my contacts at Wrox to see if they would be interested in a short MonoTouch ebook in their Wrox Blox format.  I fully expected another  response along the lines of "Wally, mobile doesn't sell."  The response I got was "Wally, iPhone is H O T, get started immediately, can you have this to me before Labor Day."  Not quite the response I expected.  Thankfully, we didn't make the Labor Day, first draft date. I kept pushing back because I had a feeling that things were not going to be quite as polished and feature rich as necessary.  After all, Novell doesn't have the resouces of Microsoft's developer division. The ebook shipped on November 30, 2009. On about December, 15, 2009, my editor emailed and said "Your ebook is selling really well, lets do a full book and it by March 1 so get started."  Thankfully, guys like Craig Dunn and Chris Hardy were interested along with Martin and Ror joinged us later on. I bought my wife an iPhone 3Gs in early 2010 to go along with all my iPod Touch devices. I tried to pretend in 2010 that I wasn't that interested in mobile and still had interest in the desktop technologies.  I love the technologies and continue to use them today, but that isn't where my interest is right now.  I'm just about all mobile all the time with my energies.  Our book shipped in the beginning of July, 2010 right in the middle of the Apple FUD.I've been looking at Mobile Web as a way around the AppStores and Apple FUD problems of 2010. With all the Apple self FUD, we became interested in Android.I went up to Dino Esposito at DevConnections in Las Vegas at introduced myself. I've always tried to keep up with what Dino has been doing. I was shocked, he wanted to meet me.  We must have talked for 1.5 hours. It was way more time than I deserved. If you get a chance, go and introduce yourself to Dino. He's a great guy. Microsoft released Windows Phone 7 in the Fall of 2010.  I'm not doing development on that platform at this time.  I think they have a very interesting user interface.  The devices are being positively reviewed.  For my purposes, the devices are limited at this point in time.  We'll see what 2011 brings as far as updates to the operating system.  I need multitasking/background processing and html5 in the browser. Add that as well as acceptance in the marketplace and I'll be more interested in the device. Obviosuly, I'm now working on a MonoDroid book . I own Android and iPhone/iOS devices.  I am currently working on some startup ideas and am exploring as much in that area as I can. For 2011, I'm planning on speaking at Android Developer's Conference (AnDevCon) and Mobile Connections.  I'm really excited about this. I have a couple of magazine articles coming out in 2011 on Android and iPhone development with the Mono technologies.is Mono "The Answer"? What's "The Question?" I think it will work for me.  It might work for you, it might not.  it depends on your situation.  Its the current horse that I am riding. I might find a better horse tomorrow. So, that's how I got here.  I'm in love with mobile.  Mobile native apps on the device as well as mobile web.  I'm into all this cool stuff.  Where are you at?

    Read the article

  • Bash vs. Gnu screen : Replace Ctrl-A with Ctrl-Shift-A

    - by Stefan Lasiewski
    I'm a new user to GNU Screen. I've been using Bash for a very long time, and I want to give GNU Screen a try. As you know, GNU Screen uses 'C-a' (Control-A) as as the command character. Trouble is, this interferes with the Line Editing feature in Bash (and GNU Readline), because Control-A in Bash will Move to the start of the line." I know I can set the Command Character to another key sequence, like "^Q" or "``" (Backtick), but I have trouble finding another key sequence which isn't already in use (^Q is used by the terminal, backtick is used when writing shell scripts). It appears that the Command Character may only be one or two characters in length. Can I set the GNU Screen control character to be something like "Control-Shift-A"? (I can't use more then one hyperlink yet, so I cannot link to the Bash documentation)

    Read the article

  • Aging vs. Coding Skills

    - by Renan Malke Stigliani
    A little background, since it can be part of my point fo view. I'm a C#/Java programmer with age of 23, coding since my 18's. I started studying C and working with Cobol, and after 1 year I quickly moved to C#/Java Web Development, and have worked with it in about 3/4 companies. (I've just moved again) In my (brief) professional career I encountered some older programmers, all the times it was very hard to work with them, since I was way better programmer than they. And it is not about just the language skills, some of them had seriously problems understanding basic logic. Now I wonder how theese programmer get jobs on the market since (I imagine) they have more expenses, and thus have to make more money, and are really counter-productives. In theese examples, others project member have to constantly keep stoping for helping them out. All the times, they eventually quit... So I wonder... May the aging process slow down the learning rate and logic thinking? Does the programmer has to, or at least should, move to a management area before getting old? Please, my intention is not to be disrespectful with older persons. I am fully aware that this is NOT the case of all older programmers, I often see around very good old programmers on the net, I just never met them for close.

    Read the article

  • The fastest way to resize images from ASP.NET. And it’s (more) supported-ish.

    - by Bertrand Le Roy
    I’ve shown before how to resize images using GDI, which is fairly common but is explicitly unsupported because we know of very real problems that this can cause. Still, many sites still use that method because those problems are fairly rare, and because most people assume it’s the only way to get the job done. Plus, it works in medium trust. More recently, I’ve shown how you can use WPF APIs to do the same thing and get JPEG thumbnails, only 2.5 times faster than GDI (even now that GDI really ultimately uses WIC to read and write images). The boost in performance is great, but it comes at a cost, that you may or may not care about: it won’t work in medium trust. It’s also just as unsupported as the GDI option. What I want to show today is how to use the Windows Imaging Components from ASP.NET APIs directly, without going through WPF. The approach has the great advantage that it’s been tested and proven to scale very well. The WIC team tells me you should be able to call support and get answers if you hit problems. Caveats exist though. First, this is using interop, so until a signed wrapper sits in the GAC, it will require full trust. Second, the APIs have a very strong smell of native code and are definitely not .NET-friendly. And finally, the most serious problem is that older versions of Windows don’t offer MTA support for image decoding. MTA support is only available on Windows 7, Vista and Windows Server 2008. But on 2003 and XP, you’ll only get STA support. that means that the thread safety that we so badly need for server applications is not guaranteed on those operating systems. To make it work, you’d have to spin specialized threads yourself and manage the lifetime of your objects, which is outside the scope of this article. We’ll assume that we’re fine with al this and that we’re running on 7 or 2008 under full trust. Be warned that the code that follows is not simple or very readable. This is definitely not the easiest way to resize an image in .NET. Wrapping native APIs such as WIC in a managed wrapper is never easy, but fortunately we won’t have to: the WIC team already did it for us and released the results under MS-PL. The InteropServices folder, which contains the wrappers we need, is in the WicCop project but I’ve also included it in the sample that you can download from the link at the end of the article. In order to produce a thumbnail, we first have to obtain a decoding frame object that WIC can use. Like with WPF, that object will contain the command to decode a frame from the source image but won’t do the actual decoding until necessary. Getting the frame is done by reading the image bytes through a special WIC stream that you can obtain from a factory object that we’re going to reuse for lots of other tasks: var photo = File.ReadAllBytes(photoPath); var factory = (IWICComponentFactory)new WICImagingFactory(); var inputStream = factory.CreateStream(); inputStream.InitializeFromMemory(photo, (uint)photo.Length); var decoder = factory.CreateDecoderFromStream( inputStream, null, WICDecodeOptions.WICDecodeMetadataCacheOnLoad); var frame = decoder.GetFrame(0); We can read the dimensions of the frame using the following (somewhat ugly) code: uint width, height; frame.GetSize(out width, out height); This enables us to compute the dimensions of the thumbnail, as I’ve shown in previous articles. We now need to prepare the output stream for the thumbnail. WIC requires a special kind of stream, IStream (not implemented by System.IO.Stream) and doesn’t directlyunderstand .NET streams. It does provide a number of implementations but not exactly what we need here. We need to output to memory because we’ll want to persist the same bytes to the response stream and to a local file for caching. The memory-bound version of IStream requires a fixed-length buffer but we won’t know the length of the buffer before we resize. To solve that problem, I’ve built a derived class from MemoryStream that also implements IStream. The implementation is not very complicated, it just delegates the IStream methods to the base class, but it involves some native pointer manipulation. Once we have a stream, we need to build the encoder for the output format, which could be anything that WIC supports. For web thumbnails, our only reasonable options are PNG and JPEG. I explored PNG because it’s a lossless format, and because WIC does support PNG compression. That compression is not very efficient though and JPEG offers good quality with much smaller file sizes. On the web, it matters. I found the best PNG compression option (adaptive) to give files that are about twice as big as 100%-quality JPEG (an absurd setting), 4.5 times bigger than 95%-quality JPEG and 7 times larger than 85%-quality JPEG, which is more than acceptable quality. As a consequence, we’ll use JPEG. The JPEG encoder can be prepared as follows: var encoder = factory.CreateEncoder( Consts.GUID_ContainerFormatJpeg, null); encoder.Initialize(outputStream, WICBitmapEncoderCacheOption.WICBitmapEncoderNoCache); The next operation is to create the output frame: IWICBitmapFrameEncode outputFrame; var arg = new IPropertyBag2[1]; encoder.CreateNewFrame(out outputFrame, arg); Notice that we are passing in a property bag. This is where we’re going to specify our only parameter for encoding, the JPEG quality setting: var propBag = arg[0]; var propertyBagOption = new PROPBAG2[1]; propertyBagOption[0].pstrName = "ImageQuality"; propBag.Write(1, propertyBagOption, new object[] { 0.85F }); outputFrame.Initialize(propBag); We can then set the resolution for the thumbnail to be 96, something we weren’t able to do with WPF and had to hack around: outputFrame.SetResolution(96, 96); Next, we set the size of the output frame and create a scaler from the input frame and the computed dimensions of the target thumbnail: outputFrame.SetSize(thumbWidth, thumbHeight); var scaler = factory.CreateBitmapScaler(); scaler.Initialize(frame, thumbWidth, thumbHeight, WICBitmapInterpolationMode.WICBitmapInterpolationModeFant); The scaler is using the Fant method, which I think is the best looking one even if it seems a little softer than cubic (zoomed here to better show the defects): Cubic Fant Linear Nearest neighbor We can write the source image to the output frame through the scaler: outputFrame.WriteSource(scaler, new WICRect { X = 0, Y = 0, Width = (int)thumbWidth, Height = (int)thumbHeight }); And finally we commit the pipeline that we built and get the byte array for the thumbnail out of our memory stream: outputFrame.Commit(); encoder.Commit(); var outputArray = outputStream.ToArray(); outputStream.Close(); That byte array can then be sent to the output stream and to the cache file. Once we’ve gone through this exercise, it’s only natural to wonder whether it was worth the trouble. I ran this method, as well as GDI and WPF resizing over thirty twelve megapixel images for JPEG qualities between 70% and 100% and measured the file size and time to resize. Here are the results: Size of resized images   Time to resize thirty 12 megapixel images Not much to see on the size graph: sizes from WPF and WIC are equivalent, which is hardly surprising as WPF calls into WIC. There is just an anomaly for 75% for WPF that I noted in my previous article and that disappears when using WIC directly. But overall, using WPF or WIC over GDI represents a slight win in file size. The time to resize is more interesting. WPF and WIC get similar times although WIC seems to always be a little faster. Not surprising considering WPF is using WIC. The margin of error on this results is probably fairly close to the time difference. As we already knew, the time to resize does not depend on the quality level, only the size does. This means that the only decision you have to make here is size versus visual quality. This third approach to server-side image resizing on ASP.NET seems to converge on the fastest possible one. We have marginally better performance than WPF, but with some additional peace of mind that this approach is sanctioned for server-side usage by the Windows Imaging team. It still doesn’t work in medium trust. That is a problem and shows the way for future server-friendly managed wrappers around WIC. The sample code for this article can be downloaded from: http://weblogs.asp.net/blogs/bleroy/Samples/WicResize.zip The benchmark code can be found here (you’ll need to add your own images to the Images directory and then add those to the project, with content and copy if newer in the properties of the files in the solution explorer): http://weblogs.asp.net/blogs/bleroy/Samples/WicWpfGdiImageResizeBenchmark.zip WIC tools can be downloaded from: http://code.msdn.microsoft.com/wictools To conclude, here are some of the resized thumbnails at 85% fant:

    Read the article

  • How do you deal with translating theory into practice?

    - by Mr. Shickadance
    Hello all! Being a computer scientist in a research field I am often tasked with working alongside professionals outside of the software domain (think math people, electrical engineer etc), and then translating their theories and ideas into real-world implementations. I often find it difficult when they present a theoretical problem which appears to be somewhat disconnected from reality. I am not saying that the theory is bogus, only that it is difficult to translate into real-world situations. For example, recently I have been working with software defined radios. We are exploring many different areas, but often the math specialists in my group would present a problem which is heavily grounded in theory (signal processing, physics, whatever). I often struggle at times where it is hard to draw direct parallels between the theory and the real-world implementation that I need to develop. Say we are working on an energy detector, the theory person in my group would say "you need to measure the noise variance with no signal present." This leads me to think "how the hell do I isolate noise from a signal in reality?" There are many examples, but I hope you see where I am going. So, my question is how does one deal with implementation of theoretical concepts when the theory seems detached from reality? Or at least when the connections are not so clear. Or perhaps, the person with the 'theory' may be ignorant of real restrictions? Note: I found this to be a hard question to ask - hopefully you are following me. If you have suggestions on how I could improve it, by all means let me know! Thanks for looking! EDIT: To be a bit more clear, I understand in situations like this that I must learn that specific domain myself to an extent (i.e. signal processing), but I am more concerned with when those theoretical concepts do not appear to be as grounded in practice as one would like.

    Read the article

  • Linux SW Raid: whole disk or per-partition?

    - by Steve Pomeroy
    I have inherited a machine which has 2 physical disks and uses Linux SW RAID(1). Both disks are partitioned and are are all individual arrays (/dev/md0, /dev/md6, etc.). Those arrays are then mounted (/boot, /home, etc. even /tmp). As RAID is designed to mitigate physical failures, is there any reason why one would use this technique over whole-disk arrays that are then partitioned (perhaps using LVM)? This seems prone to more potential issues, but may have some special properties that I haven't been able to glean. I'm planning on moving this setup to: disks?SWRAID(1)?LVM as I'll be making multiple VMs out of the one machine, but wanted to make sure I knew what I was doing when I got rid of the old setup.

    Read the article

  • A client wants us to screen work machines for pornography. Is it possible?

    - by Scant Roger
    A long-time client has asked us to help screen their work machines for pornography. They're worried about liability if sensitive materials were found. Their main concerns (for obvious reasons) are video, audio, and image files. If possible, they'd also like to scan text-based documents for inappropriate content. They have a hierarchy of not-for-work content starting with blatantly illegal (I don't have to list details), moving down to obviously offensive, and also including things that may be offensive to some - think lingerie ads, joke cards featuring butt cracks, and anything related to Howie Mandel. My questions are: Is this ethical? I think it is since every employee legally agrees that their work machine belongs to the company and is subject to search. The screenings are not to occur on personal machines brought to work. Is it feasible? I've done a lot of image processing/indexing but this seems like a whole new world of complexity. Any references to successful techniques for discovering porn? Is it appropriate for me to archive the results when something is discovered?

    Read the article

  • Retrieving an RSA key from a running instance of Apache?

    - by Nathan Osman
    I created an RSA keypair for an SSL certificate and stored the private key in /etc/ssl/private/server.key. Unfortunately this was the only copy of the private key that I had. Then I accidentally overwrote the file on disk (yes, I know). Apache is still running and still serving SSL requests, leading me to believe that there may be hope in recovering the private key. (Perhaps there is a symbolic link somewhere in /proc or something?) This server is running Ubuntu 12.04 LTS.

    Read the article

  • Reverse DNS does not match SMTP Banner

    - by Bastien974
    Hi all, I had this Warning with mxtoolbox. I know that it's not necessarily a big problem, but since we are having lots of issue with email delivery, I want to check everything. I have a Exchange server 07 + Sonicwall. My FQDN is office.mydomain.ca for send/receive connectors. When I try : telnet office.mydomain.ca 25 -- 220 MYSERVER.mydomain.local Microsoft ESMTP MAIL Service ready at Fri, 7 May 2010 10:34:36 -0400 I can change my SMTP Banner in the Sonicwall, but I don't know what to write, if there is a specific syntax or what can be the consequence if it doesn't work. Thanks for your help.

    Read the article

  • Dell Latitude e6520 gaming capabilities?

    - by user1072185
    I am purchasing a very reduced Dell Latitude e6520 from a friend and was wondering what kinds of games I could play on it and what resolutions. I'm not buying it for gaming purposes, but I am curious. The specs are as follows: Intel® Core™ i7-2720QM (2.20GHz, 6M cache) with Turbo BoostTechnology 2.0 nVidia® NVS™ 4200M 512MB DDR3 Discrete Graphics for Quad Core upon further research, the CPU requires this graphic card. 4.0GB, DDR3-1333MHz SDRAM 500GB 7200rpm Hard Drive I may upgrade to 8GB memory, depending if I am bogged down, what do you guys think?

    Read the article

  • UEFI/GPT Win 7 Load Failure in Dual Boot and no GRUB2 [Ubuntu 12.04]

    - by cristian_jordache
    Configuration: MBB: ASRock X79 Extreme6 Win 7 installed on a INTEL 40GB SSD (GPT partitioned) Ubuntu 14.04 on a CORSAIR 30GB SSD (Ext4 and SWAP) I had Windows 7 installed previously in UEFI mode, using 3 partitions (GPT) and works fine if left alone. In UEFI BIOS settings I can see sometimes a "Windows Boot Manager" and other times (?) a "UEFI Intel" entry for INTEL HDD and Windows will boot properly selecting the one available at that time. I installed Ubuntu 14.04 after Win 7 w/o changing any UEFI BIOS settings and it works fine only if the BIOS is set w/ the Ubuntu partition as the first drive to boot, in AHCI mode. If both SSD drives are connected, the Win7 Intel boot drive can be chosen as first boot device but only as an "AHCI Intel drive" (No "Windows Boot Manager" nor "UEFI Intel device" options available in BIOS Boot menu) and Win7 will not load properly as long as the Ubuntu Crucial SSD is NOT PHYSICALLY DISCONNECTED. Windows will try, start booting for few seconds but will fail replacing Win7 logo and that startup animation with w/ the "old" white progress bar and then and will notify that there is a issue and prompt the user to try to Load Win 7 in Normal Mode again or try a Recovery Mode to fix it. If I let Windows INTEL HDD boot via BIOS/UEFI - Windows Boot manager selection, I may see the purple screen of Grub2 loaded for a while, but there's no selection for Ubuntu or Windows and/or then machine is not booting, showing a black screen and a small command prompt cursor blinking on top. So far the only option I see to have Ubuntu boot side by side w/ Win 7 is to reformat the Win7 SDD and set it boot in legacy BIOS mode with a MBR instead of GPT. Per my understanding this is a quite complex issue to fix (Rod Smith's answer was pretty helpful: UEFI boot on my Asus k52f) but any other suggestions are welcome. I find a bit odd that I can boot properly Windows7 SSD or an Ubuntu DVD using a DVD drive set in UEFI-BIOS in "AHCI mode" and w/ using "UEFI/Windows Boot Manager" booting option but I cannot boot a secondary SSD-HDD w/ Ubuntu having the same BIOS/UEFI Boot configuration. Looks like plugging the second SSD [the Ubuntu partition] is interfering with boot options in UEFI-BIOS.

    Read the article

  • Why is this LTO4 Tape-drive not working

    - by Tim Haegele
    # modprobe mptsas # dmesg [ 4274.796796] scsi target7:0:0: mptsas: ioc1: delete device: fw_channel 0, fw_id 0, phy 0, sas_addr 0x50050763124b29ac [ 4274.939579] mptsas 0000:01:00.0: PCI INT A disabled [ 4280.934531] Fusion MPT SAS Host driver 3.04.12 [ 4280.934552] mptsas 0000:01:00.0: PCI INT A -> GSI 16 (level, low) -> IRQ 16 [ 4280.934692] mptbase: ioc2: Initiating bringup [ 4281.490183] ioc2: LSISAS1064E B3: Capabilities={Initiator} [ 4281.490203] mptsas 0000:01:00.0: setting latency timer to 64 [ 4293.555274] scsi8 : ioc2: LSISAS1064E B3, FwRev=011e0000h, Ports=1, MaxQ=277, IRQ=16 [ 4293.574906] mptsas: ioc2: attaching ssp device: fw_channel 0, fw_id 0, phy 0, sas_addr 0x50050763124b29ac [ 4293.576471] scsi 8:0:0:0: Sequential-Access IBM ULTRIUM-HH4 B6W1 PQ: 0 ANSI: 6 [ 4293.578549] st 8:0:0:0: Attached scsi tape st0 [ 4293.578550] st 8:0:0:0: st0: try direct i/o: yes (alignment 512 B) [ 4293.578577] st 8:0:0:0: Attached scsi generic sg5 type 1 # mt -f /dev/st0 status mt -f /dev/st0 status mt: /dev/st0: rmtopen failed: Input/output error # dd if=/dev/zero of=/dev/nst0 bs=1024 count=10 dd: opening `/dev/nst0': Input/output error I am running debian squeeze 2.6.32-5-amd64 #1 SMP Sun May 6 04:00:17 UTC 2012 x86_64 GNU/Linux Server is Fujitsu TX140 with Controller Symbios Logic SAS1064ET PCI-Express Fusion-MPT SAS Tape+Hardware is new.

    Read the article

< Previous Page | 397 398 399 400 401 402 403 404 405 406 407 408  | Next Page >