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  • Test the sequentiality of a column with a single SQL query

    - by LauriE
    Hey, I have a table that contains sets of sequential datasets, like that: ID set_ID some_column n 1 'set-1' 'aaaaaaaaaa' 1 2 'set-1' 'bbbbbbbbbb' 2 3 'set-1' 'cccccccccc' 3 4 'set-2' 'dddddddddd' 1 5 'set-2' 'eeeeeeeeee' 2 6 'set-3' 'ffffffffff' 2 7 'set-3' 'gggggggggg' 1 At the end of a transaction that makes several types of modifications to those rows, I would like to ensure that within a single set, all the values of "n" are still sequential (rollback otherwise). They do not need to be in the same order according to the PK, just sequential, like 1-2-3 or 3-1-2, but not like 1-3-4. Due to the fact that there might be thousands of rows within a single set I would prefer to do it in the db to avoid the overhead of fetching the data just for verification after making some small changes. Also there is the issue of concurrency. The way locking in InnoDB (repeatable read) works (as I understand) is that if I have an index on "n" then InnoDB also locks the "gaps" between values. If I combine set_ID and n to a single index, would that eliminate the problem of phantom rows appearing? Looks to me like a common problem. Any brilliant ideas? Thanks! Note: using MySQL + InnoDB

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  • is there something equivalent to 'Address of' or offset operator in .net?

    - by Gio
    We have nested stuctures as such, used as an interface for some device drivers. On occasion we have to update individual elements. An 'address of' operator would be helpful, but an 'offset' function or operator is what I'm really looking for, but not sure how to go about it. In other words, how far is structureN.elementX away from the start of the structure in bytes? [StructLayout(LayoutKind.Sequential)] public struct s1 { UInt16 elem1; UInt16 elem2; UInt16 elem3; } [StructLayout(LayoutKind.Sequential)] public struct s2 { UInt16 elem1; UInt16 elem2; UInt16 elem3; } [StructLayout(LayoutKind.Sequential)] public struct driver { public S1 s1; public S2 s2; } For instance we need to send the device driver some data to update driver.s1.elem3, by way of providing an offset address, data block and length. We would update our local copy, then call the device api with the afore mentioned data. Not sure I have to do this with 'unsafe' method calls. Any help?

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  • KVM slow guest i/o

    - by Akarot
    Host: Debian 6.0 (squeeze) with qemu-kvm and libvirt from squeeze-backports ii qemu-kvm 1.0+dfsg-8~bpo60+1 ii libvirt-bin 0.9.8-2~bpo60+2 Has 3TB sata drives with software raid and lvm. It has a sequential write speed of ~140MB/s measured with dd bs=1M count=512 if=/dev/zero of=test conv=fdatasync Elevator set to cfq Guest Debian 6.0 (squeeze) Uses LVM as storage. Drivers are virtio and cache='none' Sequential write speed is considerably slower with only 25-50MB/s Elevator set to noop I'm kind of running out of ideas for further tweaks but I'm sure that I/O speed should be much faster because many people are reporting almost native performance with lvm.

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  • What is logical cohesion, and why is it bad or undesirable?

    - by Matt Fenwick
    From the c2wiki page on coupling & cohesion: Cohesion (interdependency within module) strength/level names : (from worse to better, high cohesion is good) Coincidental Cohesion : (Worst) Module elements are unrelated Logical Cohesion : Elements perform similar activities as selected from outside module, i.e. by a flag that selects operation to perform (see also CommandObject). i.e. body of function is one huge if-else/switch on operation flag Temporal Cohesion : operations related only by general time performed (i.e. initialization() or FatalErrorShutdown?()) Procedural Cohesion : Elements involved in different but sequential activities, each on different data (usually could be trivially split into multiple modules along linear sequence boundaries) Communicational Cohesion : unrelated operations except need same data or input Sequential Cohesion : operations on same data in significant order; output from one function is input to next (pipeline) Informational Cohesion: a module performs a number of actions, each with its own entry point, with independent code for each action, all performed on the same data structure. Essentially an implementation of an abstract data type. i.e. define structure of sales_region_table and its operators: init_table(), update_table(), print_table() Functional Cohesion : all elements contribute to a single, well-defined task, i.e. a function that performs exactly one operation get_engine_temperature(), add_sales_tax() (emphasis mine). I don't fully understand the definition of logical cohesion. My questions are: what is logical cohesion? Why does it get such a bad rap (2nd worst kind of cohesion)?

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  • Data Structure for Small Number of Agents in a Relatively Big 2D World

    - by Seçkin Savasçi
    I'm working on a project where we will implement a kind of world simulation where there is a square 2D world. Agents live on this world and make decisions like moving or replicating themselves based on their neighbor cells(world=grid) and some extra parameters(which are not based on the state of the world). I'm looking for a data structure to implement such a project. My concerns are : I will implement this 3 times: sequential, using OpenMP, using MPI. So if I can use the same structure that will be quite good. The first thing comes up is keeping a 2D array for the world and storing agent references in it. And simulate the world for each time slice by checking every cell in each iteration and further processing if an agents is found in the cell. The downside is what if I have 1000x1000 world and only 5 agents in it. It will be an overkill for both sequential and parallel versions to check each cell and look for possible agents in them. I can use quadtree and store agents in it, but then how can I get the information about neighbor cells then? Please let me know if I should elaborate more.

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  • List of Commonly Used Value Types in XNA Games

    - by Michael B. McLaughlin
    Most XNA programmers are concerned about generating garbage. More specifically about allocating GC-managed memory (GC stands for “garbage collector” and is both the name of the class that provides access to the garbage collector and an acronym for the garbage collector (as a concept) itself). Two of the major target platforms for XNA (Windows Phone 7 and Xbox 360) use variants of the .NET Compact Framework. On both variants, the GC runs under various circumstances (Windows Phone 7 and Xbox 360). Of concern to XNA programmers is the fact that it runs automatically after a fixed amount of GC-managed memory has been allocated (currently 1MB on both systems). Many beginning XNA programmers are unaware of what constitutes GC-managed memory, though. So here’s a quick overview. In .NET, there are two different “types” of types: value types and reference types. Only reference types are managed by the garbage collector. Value types are not managed by the garbage collector and are instead managed in other ways that are implementation dependent. For purposes of XNA programming, the important point is that they are not managed by the GC and thus do not, by themselves, increment that internal 1 MB allocation counter. (n.b. Structs are value types. If you have a struct that has a reference type as a member, then that reference type, when instantiated, will still be allocated in the GC-managed memory and will thus count against the 1 MB allocation counter. Putting it in a struct doesn’t change the fact that it gets allocated on the GC heap, but the struct itself is created outside of the GC’s purview). Both value types and reference types use the keyword ‘new’ to allocate a new instance of them. Sometimes this keyword is hidden by a method which creates new instances for you, e.g. XmlReader.Create. But the important thing to determine is whether or not you are dealing with a value types or a reference type. If it’s a value type, you can use the ‘new’ keyword to allocate new instances of that type without incrementing the GC allocation counter (except as above where it’s a struct with a reference type in it that is allocated by the constructor, but there are no .NET Framework or XNA Framework value types that do this so it would have to be a struct you created or that was in some third-party library you were using for that to even become an issue). The following is a list of most all of value types you are likely to use in a generic XNA game: AudioCategory (used with XACT; not available on WP7) AvatarExpression (Xbox 360 only, but exposed on Windows to ease Xbox development) bool BoundingBox BoundingSphere byte char Color DateTime decimal double any enum (System.Enum itself is a class, but all enums are value types such that there are no GC allocations for enums) float GamePadButtons GamePadCapabilities GamePadDPad GamePadState GamePadThumbSticks GamePadTriggers GestureSample int IntPtr (rarely but occasionally used in XNA) KeyboardState long Matrix MouseState nullable structs (anytime you see, e.g. int? something, that ‘?’ denotes a nullable struct, also called a nullable type) Plane Point Quaternion Ray Rectangle RenderTargetBinding sbyte (though I’ve never seen it used since most people would just use a short) short TimeSpan TouchCollection TouchLocation TouchPanelCapabilities uint ulong ushort Vector2 Vector3 Vector4 VertexBufferBinding VertexElement VertexPositionColor VertexPositionColorTexture VertexPositionNormalTexture VertexPositionTexture Viewport So there you have it. That’s not quite a complete list, mind you. For example: There are various structs in the .NET framework you might make use of. I left out everything from the Microsoft.Xna.Framework.Graphics.PackedVector namespace, since everything in there ventures into the realm of advanced XNA programming anyway (n.b. every single instantiable thing in that namespace is a struct and thus a value type; there are also two interfaces but interfaces cannot be instantiated at all and thus don’t figure in to this discussion). There are so many enums you’re likely to use (PlayerIndex, SpriteSortMode, SpriteEffects, SurfaceFormat, etc.) that including them would’ve flooded the list and reduced its utility. So I went with “any enum” and trust that you can figure out what the enums are (and it’s rare to use ‘new’ with an enum anyway). That list also doesn’t include any of the pre-defined static instances of some of the classes (e.g. BlendState.AlphaBlend, BlendState.Opaque, etc.) which are already allocated such that using them doesn’t cause any new allocations and therefore doesn’t increase that 1 MB counter. That list also has a few misleading things. VertexElement, VertexPositionColor, and all the other vertex types are structs. But you’re only likely to ever use them as an array (for use with VertexBuffer or DynamicVertexBuffer), and all arrays are reference types (even arrays of value types such as VertexPositionColor[ ] or int[ ]). * So that’s it for now. The note below may be a bit confusing (it deals with how the GC works and how arrays are managed in .NET). If so, you can probably safely ignore it for now but feel free to ask any questions regardless. * Arrays of value types (where the value type doesn’t contain any reference type members) are much faster for the GC to examine than arrays of reference types, so there is a definite benefit to using arrays of value types where it makes sense. But creating arrays of value types does cause the GC’s allocation counter to increase. Indeed, allocating a large array of a value type is one of the quickest ways to increment the allocation counter since a .NET array is a sequential block of memory. An array of reference types is just a sequential block of references (typically 4 bytes each) while an array of value types is a sequential block of instances of that type. So for an array of Vector3s it would be 12 bytes each since each float is 4 bytes and there are 3 in a Vector3; for an array of VertexPositionNormalTexture structs it would typically be 32 bytes each since it has two Vector3s and a Vector2. (Note that there are a few additional bytes taken up in the creation of an array, typically 12 but sometimes 16 or possibly even more, which depend on the implementation details of the array type on the particular platform the code is running on).

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  • Does Ruby on Rails "has_many" array provide data on a "need to know" basis?

    - by Jian Lin
    On Ruby on Rails, say, if the Actor model object is Tom Hanks, and the "has_many" fans is 20,000 Fan objects, then actor.fans gives an Array with 20,000 elements. Probably, the elements are not pre-populated with values? Otherwise, getting each Actor object from the DB can be extremely time consuming. So it is on a "need to know" basis? So does it pull data when I access actor.fans[500], and pull data when I access actor.fans[0]? If it jumps from each record to record, then it won't be able to optimize performance by doing sequential read, which can be faster on the hard disk because those records could be in the nearby sector / platter layer -- for example, if the program touches 2 random elements, then it will be faster just to read those 2 records, but what if it touches all elements in random order, then it may be faster just to read all records in a sequential way, and then process the random elements. But how will RoR know whether I am doing only a few random elements or all elements in random?

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  • Making an ANT Macro more reusable

    - by 1ndivisible
    I have a simple macro (simplified version below). At the moment it assumes that there will be a single value for a single argument, however there might be multiple values for that argument. How can I pass in 0+ values for that argument so that the macro is usable in situations where I need to pass in 0+ values for that argument, not just a single value <macrodef name="test"> <attribute name="target.dir" /> <attribute name="arg.value" /> <sequential> <java jar="${some.jar}" dir="@{target.dir}" fork="true" failonerror="true"> <arg value="-someargname=@{arg.value}"/> </java> </sequential> </macrodef>

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  • Can Atom be used for things besides syndication feeds?

    - by greim
    Purely in terms of its conceptual model, is the purpose of Atom (and RSS) only to provide a time-sequential series of frequently-updated items, such as "most recent blog posts" or "last twenty SVN commits," or can Atom be legitimately used to represent static and/or non-time-sequential listings/indices? As an example, "index of files under this directory", "dog breeds" or "music genres". Even if there's a date associated with the items, like a file's last modified date, what if you don't necessarily want time to be the primary consideration when you represent that model to your users? The context for this is passing around (generating and consuming) lists of things in a REST-ful environment, hopefully using a well-understood format, where "date something was created/updated" is a pertinent detail, but not the primary consideration. I realize there's probably no right answer, but wanted to get some perspectives. Thanks.

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  • ant: iterator over properties file

    - by scheibenkleister
    Hi, all my projects and their versions are defined in a properties file like this: ProjectNameA=0.0.1 ProjectNameB=1.4.2 I'd like to iterate over all projects and use there names and versions in an ant script. Right now, I read the entire properties file in help of the property task. Then I iterate over a given list in a for loop like this: <for list="ProjectNameA,ProjectNameB" param="project"> <sequential> <echo message="@{project} has version ${@{project}}" /> </sequential> </for> How can I avoid the duplication of the project names in the for loop. So basically iterate over each line and extract the name and the version of a project. Thanks.

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  • What .NET UnmanagedType is Unicode (UTF-16)?

    - by Pat
    I am packing bytes into a struct, and some of them correspond to a Unicode string. The following works fine for an ASCII string: [StructLayout(LayoutKind.Sequential)] private struct PacketBytes { [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 64)] public string MyString; } I assumed that I could do [StructLayout(LayoutKind.Sequential)] private struct PacketBytes { [MarshalAs(UnmanagedType.LPWStr, SizeConst = 32)] public string MyString; } to make it Unicode, but that didn't work. (Since this field is part of a struct with other fields, which I've omitted for clarity, I can't simply change the CharSet of the containing struct.) Any idea what I'm doing wrong?

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  • From Binary to Data Structures

    - by Cédric Menzi
    Table of Contents Introduction PE file format and COFF header COFF file header BaseCoffReader Byte4ByteCoffReader UnsafeCoffReader ManagedCoffReader Conclusion History This article is also available on CodeProject Introduction Sometimes, you want to parse well-formed binary data and bring it into your objects to do some dirty stuff with it. In the Windows world most data structures are stored in special binary format. Either we call a WinApi function or we want to read from special files like images, spool files, executables or may be the previously announced Outlook Personal Folders File. Most specifications for these files can be found on the MSDN Libarary: Open Specification In my example, we are going to get the COFF (Common Object File Format) file header from a PE (Portable Executable). The exact specification can be found here: PECOFF PE file format and COFF header Before we start we need to know how this file is formatted. The following figure shows an overview of the Microsoft PE executable format. Source: Microsoft Our goal is to get the PE header. As we can see, the image starts with a MS-DOS 2.0 header with is not important for us. From the documentation we can read "...After the MS DOS stub, at the file offset specified at offset 0x3c, is a 4-byte...". With this information we know our reader has to jump to location 0x3c and read the offset to the signature. The signature is always 4 bytes that ensures that the image is a PE file. The signature is: PE\0\0. To prove this we first seek to the offset 0x3c, read if the file consist the signature. So we need to declare some constants, because we do not want magic numbers.   private const int PeSignatureOffsetLocation = 0x3c; private const int PeSignatureSize = 4; private const string PeSignatureContent = "PE";   Then a method for moving the reader to the correct location to read the offset of signature. With this method we always move the underlining Stream of the BinaryReader to the start location of the PE signature.   private void SeekToPeSignature(BinaryReader br) { // seek to the offset for the PE signagure br.BaseStream.Seek(PeSignatureOffsetLocation, SeekOrigin.Begin); // read the offset int offsetToPeSig = br.ReadInt32(); // seek to the start of the PE signature br.BaseStream.Seek(offsetToPeSig, SeekOrigin.Begin); }   Now, we can check if it is a valid PE image by reading of the next 4 byte contains the content PE.   private bool IsValidPeSignature(BinaryReader br) { // read 4 bytes to get the PE signature byte[] peSigBytes = br.ReadBytes(PeSignatureSize); // convert it to a string and trim \0 at the end of the content string peContent = Encoding.Default.GetString(peSigBytes).TrimEnd('\0'); // check if PE is in the content return peContent.Equals(PeSignatureContent); }   With this basic functionality we have a good base reader class to try the different methods of parsing the COFF file header. COFF file header The COFF header has the following structure: Offset Size Field 0 2 Machine 2 2 NumberOfSections 4 4 TimeDateStamp 8 4 PointerToSymbolTable 12 4 NumberOfSymbols 16 2 SizeOfOptionalHeader 18 2 Characteristics If we translate this table to code, we get something like this:   [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)] public struct CoffHeader { public MachineType Machine; public ushort NumberOfSections; public uint TimeDateStamp; public uint PointerToSymbolTable; public uint NumberOfSymbols; public ushort SizeOfOptionalHeader; public Characteristic Characteristics; } BaseCoffReader All readers do the same thing, so we go to the patterns library in our head and see that Strategy pattern or Template method pattern is sticked out in the bookshelf. I have decided to take the template method pattern in this case, because the Parse() should handle the IO for all implementations and the concrete parsing should done in its derived classes.   public CoffHeader Parse() { using (var br = new BinaryReader(File.Open(_fileName, FileMode.Open, FileAccess.Read, FileShare.Read))) { SeekToPeSignature(br); if (!IsValidPeSignature(br)) { throw new BadImageFormatException(); } return ParseInternal(br); } } protected abstract CoffHeader ParseInternal(BinaryReader br);   First we open the BinaryReader, seek to the PE signature then we check if it contains a valid PE signature and rest is done by the derived implementations. Byte4ByteCoffReader The first solution is using the BinaryReader. It is the general way to get the data. We only need to know which order, which data-type and its size. If we read byte for byte we could comment out the first line in the CoffHeader structure, because we have control about the order of the member assignment.   protected override CoffHeader ParseInternal(BinaryReader br) { CoffHeader coff = new CoffHeader(); coff.Machine = (MachineType)br.ReadInt16(); coff.NumberOfSections = (ushort)br.ReadInt16(); coff.TimeDateStamp = br.ReadUInt32(); coff.PointerToSymbolTable = br.ReadUInt32(); coff.NumberOfSymbols = br.ReadUInt32(); coff.SizeOfOptionalHeader = (ushort)br.ReadInt16(); coff.Characteristics = (Characteristic)br.ReadInt16(); return coff; }   If the structure is as short as the COFF header here and the specification will never changed, there is probably no reason to change the strategy. But if a data-type will be changed, a new member will be added or ordering of member will be changed the maintenance costs of this method are very high. UnsafeCoffReader Another way to bring the data into this structure is using a "magically" unsafe trick. As above, we know the layout and order of the data structure. Now, we need the StructLayout attribute, because we have to ensure that the .NET Runtime allocates the structure in the same order as it is specified in the source code. We also need to enable "Allow unsafe code (/unsafe)" in the project's build properties. Then we need to add the following constructor to the CoffHeader structure.   [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)] public struct CoffHeader { public CoffHeader(byte[] data) { unsafe { fixed (byte* packet = &data[0]) { this = *(CoffHeader*)packet; } } } }   The "magic" trick is in the statement: this = *(CoffHeader*)packet;. What happens here? We have a fixed size of data somewhere in the memory and because a struct in C# is a value-type, the assignment operator = copies the whole data of the structure and not only the reference. To fill the structure with data, we need to pass the data as bytes into the CoffHeader structure. This can be achieved by reading the exact size of the structure from the PE file.   protected override CoffHeader ParseInternal(BinaryReader br) { return new CoffHeader(br.ReadBytes(Marshal.SizeOf(typeof(CoffHeader)))); }   This solution is the fastest way to parse the data and bring it into the structure, but it is unsafe and it could introduce some security and stability risks. ManagedCoffReader In this solution we are using the same approach of the structure assignment as above. But we need to replace the unsafe part in the constructor with the following managed part:   [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)] public struct CoffHeader { public CoffHeader(byte[] data) { IntPtr coffPtr = IntPtr.Zero; try { int size = Marshal.SizeOf(typeof(CoffHeader)); coffPtr = Marshal.AllocHGlobal(size); Marshal.Copy(data, 0, coffPtr, size); this = (CoffHeader)Marshal.PtrToStructure(coffPtr, typeof(CoffHeader)); } finally { Marshal.FreeHGlobal(coffPtr); } } }     Conclusion We saw that we can parse well-formed binary data to our data structures using different approaches. The first is probably the clearest way, because we know each member and its size and ordering and we have control about the reading the data for each member. But if add member or the structure is going change by some reason, we need to change the reader. The two other solutions use the approach of the structure assignment. In the unsafe implementation we need to compile the project with the /unsafe option. We increase the performance, but we get some security risks.

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  • MySQL se tourne encore plus vers InnoDB, qui sera utilisé pour les tables systèmes pour bénéficier des propriétés ACID

    MySQL se tourne encore plus vers InnoDB qui sera utilisé pour les tables systèmes pour bénéficier des propriétés ACID Depuis le rachat de MySQL par Oracle, le célèbre SGBD a entamé une lente transition de son moteur de base de données, passant du moteur d'origine MyISAM qui est basé sur la méthode ISAM (Indexed Sequential Access Methode) à InnoDB. Cette transition s'est d'ailleurs achevée partiellement par l'intronisation d'InnoDB comme moteur par défaut pour les versions de MySQL 5.5 et plus.Partiellement,...

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  • Row Number Transformation

    The Row Number Transformation calculates a row number for each row, and adds this as a new output column to the data flow. The column number is a sequential number, based on a seed value. Each row receives the next number in the sequence, based on the defined increment value. Develop seamlessly between Management Studio and Visual StudioSQL Connect is a Visual Studio add-in that makes it easy to keep your database and Visual Studio project in sync.

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  • TSQL Challenge 79 - Finding the Islands

    The challenge is to find the Islands(gaps) in sequential dates. You need to write a query to identify continuous intervals from the start date and end date. What are your servers really trying to tell you? Find out with new SQL Monitor 3.0, an easy-to-use tool built for no-nonsense database professionals.For effortless insights into SQL Server, download a free trial today.

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  • Expected IOPS for log writing on PS6000X SAN?

    - by dssz
    Customer is experiencing poor Sybase ASE 15 performance on a PS6000X SAN with 16 X 450GB 10K in RAID-50. The server is a Dell R710 running 2003 server R2 64bit in ESX 4.0.0,256968 I've used sqlio to benchmark the sequential write performance of 4KB blocks on the drive. sqlio -kW -t1 -s600 -dE -o1 -fsequential -b4 -BH -LS sqliotestfile.dat Result is 1900 IOPS. However, when Sybase is running a sustained workload of small inserts SAN HQ shows a consistent 590 IOPS (and 100% 4K write activity). It also shows that the write latency increases to 1.2ms from <1ms. Monitoring and tests in Sybase demonstrate the performance problem is IO related and in particular there is a lot of wait time writing to the log. The SAN indicates that write caching is enabled. What IOPS should the SAN be capable of for 4k sequential write activity? Also, with write caching enabled, shouldn't the controller be batching up the 4K writes into something more efficient? Also, any tips on Sybase on ESX would be appreciated.

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  • Best way to attach 96 tb to workstation

    - by user994179
    I'm running a workstation with dual xeon 5690's (12 physical/24 logical cores), 192 gb of ram (ie, maxed-out), Windows 7 64bit, 5 slots for adapter cards, and 1 tb of internal storage, with 5 more internal bays available. I have an app that creates data files totaling about 88 tbs. These are written once every 14 months, and the rest of the time the app only needs to read them; and 95% of the reads are sequential reads of huge chunks of data. I have some control over how big the individual files are, but ideally they would be between 5 and 8 tbs. The app will be reading from only one drive at a time, and the nature of the data is such that if (when) a drive dies I can restore the data to a new disk from tape. While it would be nice to be able to use the fastest drive/controllers available, at this point size matters more than speed. After doing lots of reading, I am leaning toward buying a bunch of cheap 2tb drives and putting them into a bunch of cheap enclosures. All this stuff is going into my home office, so I need to avoid the raised floor/refrigerated approach. My questions: Is the cheap drive/enclosure solution the best one for this situation? Given the nature of the app and the way the data is used, does RAID make sense? If so, which one? For huge sequential reads, would Usb 3.0 and eSata be a wash performance-wise? For each slot available on the workstation, can I hook up an enclosure that can hold multiple drives? Or is it one controller per drive? If I can have multiple drives on one controller, am I essentially splitting the bandwidth (throughput)? For example, if I have a 12 bay enclosure, is the throughput of the controller reduced by a factor of 12? Are there any Windows 7 volume/drive/capacity limits I should be aware of? Thanks

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  • what is the fastest way to copy all data to a new larger hard drive?

    - by SUPER user
    I was certain this would have been covered before, but I cannot find an answer amongst all the almost-duplicates that come up; sorry if I've missed something obvious. I have a full 320gb disk inside my machine, a new 1tb disk to replace it, and a USB 2.0 chassis. It is only data on a single partition, no OS/apps involved, and the old drive will be kept somewhere as backup (no secure wiping etc). The simple option would be to put new disk in USB chassis, copy files, then swap them over. But for USB pen drives, reading is around 4x faster than writing. If the same is true for a USB SATA chassis (is it?) then it would be significantly faster to swap the drives first and read from the old drive over USB, right? Then the other consideration is that copying lots of files is usually slower than a single file of equivalent size. Is Windows 7 smart enough to do everything in a single lump like that, or is there specialised software that should be used instead? (Even if SATA-SATA copying is faster than involving USB, knowing what to do when it isn't an option is useful information.) Summary: Does a USB SATA chassis suffer from a read/write inequality? (like a USB pen drive does, but unlike a direct SATA connection) Can Windows 7 do sequential access? (I can't find confirmation if Robocopy does this.) Or is it necessary to use a bootable CD/USB with something like Clonezilla to achieve sequential copy speeds?

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  • Selenium &ndash; Use Data Driven tests to run in multiple browsers and sizes

    - by Aligned
    Originally posted on: http://geekswithblogs.net/Aligned/archive/2013/11/04/selenium-ndash-use-data-driven-tests-to-run-in-multiple.aspxSelenium uses WebDriver (or is it the same? I’m still learning how it is connected) to run Automated UI tests in many different browsers. For example, you can run the same test in Chrome and Firefox and in a smaller sized Chrome browser. The permutations can grow quickly. One way to get them to run in MStest is to create  a test method for each test (ie ChromeDeleteItem_Small, ChromeDeleteItem_Large, FFDeleteItem_Small, FFDeleteItem_Large) that each call  the same base method, passing in the browser and size you’d like. This approach was causing a lot of duplicate code, so I decided to use the data driven approach, common to Coded UI or Unit test methods. 1. Create a class with a test method. 2. Create a csv with two columns: BrowserType, BrowserSize 3. Add rows for each permutation: Chrome, Large | Chrome, Small | Firefox, Large | Firefox, Small | IE, Large | IE, Small | *** 4. Add the csv to the Visual Studio Project. 5. Set the Copy to output directory to Copy always 6. Add the attribute: [DataSource("Microsoft.VisualStudio.TestTools.DataSource.CSV", "|DataDirectory|\\TestMatrix.csv", "TestMatrix#csv", DataAccessMethod.Sequential), DeploymentItem("TestMatrix.csv")] 7. Run the test in the test explorer Example:[CodedUITest] public class AllTasksTests : TasksTestBase { [TestMethod] [TestCategory("Tasks")] [DataSource("Microsoft.VisualStudio.TestTools.DataSource.CSV", "|DataDirectory|\\TestMatrix.csv", "TestMatrix#csv", DataAccessMethod.Sequential), DeploymentItem("TestMatrix.csv")] public void CreateTask() { this.PrepForDataDrivenTest(); base.CreateTaskTest("New Task"); } } protected void PrepForDataDrivenTest() { var browserType = this.ParseBrowserType(Context.DataRow["BrowserType"].ToString()); var browserSize = this.ParseBrowserSize(Context.DataRow["BrowserSize"].ToString()); this.BrowserType = browserType; this.BrowserSize = browserSize; Trace.WriteLine("browser: " + browserType.ToString()); Trace.WriteLine("browser size: " + browserSize.ToString()); } /// <summary> /// Get the enum value from the string /// </summary> /// <param name="browserType">Chrome, Firefox, or IE</param> /// <returns>The browser type.</returns> private BrowserType ParseBrowserType(string browserType) { return (UITestFramework.BrowserType)Enum.Parse(typeof(UITestFramework.BrowserType), browserType, true); } /// <summary> /// Get the browser size enum value from the string /// </summary> /// <param name="browserSize">Small, Medium, Large</param> /// <returns>the browser size</returns> private BrowserSizeEnum ParseBrowserSize(string browserSize) { return (BrowserSizeEnum)Enum.Parse(typeof(BrowserSizeEnum), browserSize, true); }/// <summary> /// Change the browser to the size based on the enum. /// </summary> /// <param name="browserSize">The BrowserSizeEnum value to resize the window to.</param> private void ResizeBrowser(BrowserSizeEnum browserSize) { switch (browserSize) { case BrowserSizeEnum.Large: this.driver.Manage().Window.Maximize(); break; case BrowserSizeEnum.Medium: this.driver.Manage().Window.Size = new Size(800, this.driver.Manage().Window.Size.Height); break; case BrowserSizeEnum.Small: this.driver.Manage().Window.Size = new Size(500, this.driver.Manage().Window.Size.Height); break; default: break; } }/// <summary> /// Browser sizes for automation testing /// </summary> public enum BrowserSizeEnum { /// <summary> /// Large size, Maximized to the desktop /// </summary> Large, /// <summary> /// Similar to tablets /// </summary> Medium, /// <summary> /// Phone sizes... 610px and smaller /// </summary> Small } Hope it helps!

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  • jqGrid local data manipulation; problem with row ids when deleting and adding new rows

    - by Sam
    I'm using jqGrid as a client side grid input, allowing the user to input multiple records before POSTing all the data back at once. I'm having a problem where if the user has added a few records (say 3 ) the id's for the records will be 1,2,3. if the user deletes record 2, you're left with 1 and 3 for the id of the records. When the user now adds a new records, jqGrid assigns that records the id 3 again since it just seems to count the total records and increments it by one for the new record. This causes problems when selecting rows as now the row id's are 1, 3 and 3. Does anyone know how to access the row ids of records as I could probably use the afterSubmit event and reassign the row id's increasing from 1. ( so after i delete row id 2, this will set the other row id's to 1 and 2) Any other suggestions to solve this problem? Thanks edit I've solved this with the following code for the delete navGrid button }).navGrid('#pager', {add:true, del:true, refresh:false, search:false}, { ... }, ##edit parameters { ... }, ##add parameters {reloadAfterSubmit:false, clearAfterAdd:false, afterComplete: function () { ## clear and readd the row data so the row ids are sequential var savedData= $("#inputgrid").jqGrid('getRowData'); $("#inputgrid").jqGrid('clearGridData'); $("#inputgrid").jqGrid('addRowData', 'rn', savedData); } } ##delete parameters ); Basically just saving the grid data and then re-adding it so that the rowids are sequential again. For some reason it causes the row numbers down the left side to go start from 2 instead of one. Edit this was solved by using the latest jqGrid code in GitHub (27th April 2010)

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  • How to get friendly device name from DEV_BROADCAST_DEVICEINTERFACE and Device Instance ID

    - by snicker
    I've registered a window with RegisterDeviceNotification and can successfully recieve DEV_BROADCAST_DEVICEINTERFACE messages. However, the dbcc_name field in the returned struct is always empty. The struct I have is defined as such: [StructLayout(LayoutKind.Sequential)] public struct DEV_BROADCAST_DEVICEINTERFACE { public int dbcc_size; public int dbcc_devicetype; public int dbcc_reserved; public Guid dbcc_classguid; [MarshalAs(UnmanagedType.LPStr)] public string dbcc_name; } And I'm using Marshal.PtrToStructure on the LParam of the WM_DEVICECHANGE message. Should this be working? Or even better... Is there an alternative way to get the name of a device upon connection? EDIT (02/05/2010 20:56GMT): I found out how to get the dbcc_name field to populate by doing this: [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)] public struct DEV_BROADCAST_DEVICEINTERFACE { public int dbcc_size; public int dbcc_devicetype; public int dbcc_reserved; public Guid dbcc_classguid; [MarshalAs(UnmanagedType.ByValTStr, SizeConst=255)] public string dbcc_name; } but I still need a way to get a "Friendly" name from what is int dbcc_name. It looks like the following: \?\USB#VID_05AC&PID_1294&MI_00#0#{6bdd1fc6-810f-11d0-bec7-08002be2092f} And I really just want it to say "Apple iPhone" (which is what the device is in this case).

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  • Flex, Ant, mxmlc and conditional compilation

    - by Rezmason
    My ActionScript project builds with several compile-time specified constants. They are all Booleans, and only one of them is true at any given time. The rest must be false. When I represented my build process in a bash script, I could loop through the names of all these constants, set one of them to be true and the rest to be false, then concatenate them onto a string to be inserted as a set of arguments passed to mxmlc. In Ant, looping is more complicated. I've tried the ant-contrib for tag: <mxmlc file='blah' output='blah'> <!- ... -> <for list='${commaSeparatedListOfConstNames}' param='constName'> <sequential> <define> <name>${constName}</name> <value>${constName} == ${theTrueConst}</value> <!-- (mxmlc's define arguments can be strings that are evaluated at compile time) --> </define> </sequential> </for> </mxmlc> Long story short, ant-contrib tags like the for tag can't go in the mxmlc task. So now I'm using Ant's propertyregex to take my list of arguments and format them into a set of define args, like my old bash script: <propertyregex property='defLine.first' override='false' input='${commaSeparatedListOfConstNames}' regexp='([^\|]+)\,' replace='\1,false ' /> <propertyregex property='defLine.final' input='${defLine.first}' regexp='(@{theTrueConst}\,)false' replace='\1true' /> <!-- result: -define+=CONST_ONE,false -define+=CONST_TWO,false -define+=TRUE_CONST,true --> Now my problem is, what can I do with this mxmlc argument and the mxmlc task? Apparently arg tags can go inside the mxmlc task without it throwing an error, but they don't seem to have any effect. What am I supposed to do? How do I make this work with the mxmlc task?

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  • Bibliography behaves strange in lyx.

    - by Orjanp
    Hi! I have created a Bibliography section in my document written in lyx. It uses a book layout. For some reason it did start over again when I added some more entries. The new entries was made some time later than the first ones. I just went down to key-27 and hit enter. Then it started on key-1 again. Does anyone know why it behaves like this? The lyx code is below. \begin{thebibliography}{34} \bibitem{key-6}Lego mindstorms, http://mindstorms.lego.com/en-us/default.aspx \bibitem{key-7}C.A.R. Hoare. Communicating sequential processes. Communications of the ACM, 21(8):666-677, pages 666\textendash{}677, August 1978. \bibitem{key-8}C.A.R. Hoare. Communicating sequential processes. Prentice-Hall, 1985. \bibitem{key-9}CSPBuilder, http://code.google.com/p/cspbuilder/ \bibitem{key-10}Rune Møllegård Friborg and Brian Vinter. CSPBuilder - CSP baset Scientific Workflow Modelling, 2008. \bibitem{key-11}Labview, http://www.ni.com/labview \bibitem{key-12}Robolab, http://www.lego.com/eng/education/mindstorms/home.asp?pagename=robolab \bibitem{key-13}http://code.google.com/p/pycsp/ \bibitem{key-14}Paparazzi, http://paparazzi.enac.fr \bibitem{key-15}Debian, http://www.debian.org \bibitem{key-16}Ubuntu, http://www.ubuntu.com \bibitem{key-17}GNU, http://www.gnu.org \bibitem{key-18}IVY, http://www2.tls.cena.fr/products/ivy/ \bibitem{key-19}Tkinter, http://wiki.python.org/moin/TkInter \bibitem{key-20}pyGKT, http://www.pygtk.org/ \bibitem{key-21}pyQT4, http://wiki.python.org/moin/PyQt4 \bibitem{key-22}wxWidgets, http://www.wxwidgets.org/ \bibitem{key-23}wxPython GUI toolkit, http://www.wxPython.org \bibitem{key-24}Python programming language, http://www.python.org \bibitem{key-25}wxGlade, http://wxglade.sourceforge.net/ \bibitem{key-26}http://numpy.scipy.org/ \bibitem{key-27}http://www.w3.org/XML/ \bibitem{key-1}IVY software bus, http://www2.tls.cena.fr/products/ivy/ \bibitem{key-2}sdas \bibitem{key-3}sad \bibitem{key-4}sad \bibitem{key-5}fsa \bibitem{key-6}sad \bibitem{key-7} \end{thebibliography}

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