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  • How to download files directly to disk on the iPhone os?

    - by favo
    Hi, I would like to download files directly from an URL to the disk using objective-c on the iPhone os. Currently I am using NSURLConnection to send a synchronousRequest, writing the returned NSData into a file. How can I change the download handling (still having the request beeing synchronous, it is already in a background thread) to write the data directly to disk, not using memory variables to store the complete content (only small parts)? A sample code would be appreciated. Thank you all in advance for your responses!

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  • Banshee encountered a Fatal Error (sqlite error 11: database disk image is malformed)

    - by Nik
    I am running ubuntu 10.10 Maverick Meerkat, and recently I am helping in testing out indicator-weather using the unstable buids. However there was a bug which caused my system to freeze suddenly (due to indicator-weather not ubuntu) and the only way to recover is to do a hard reset of the system. This happened a couple of times. And when i tried to open banshee after a couple of such resets I get the following fatal error which forces me to quit banshee. The screenshot is not clear enough to read the error, so I am posting it below, An unhandled exception was thrown: Sqlite error 11: database disk image is malformed (SQL: BEGIN TRANSACTION; DELETE FROM CoreSmartPlaylistEntries WHERE SmartPlaylistID IN (SELECT SmartPlaylistID FROM CoreSmartPlaylists WHERE IsTemporary = 1); DELETE FROM CoreSmartPlaylists WHERE IsTemporary = 1; COMMIT TRANSACTION) at Hyena.Data.Sqlite.Connection.CheckError (Int32 errorCode, System.String sql) [0x00000] in <filename unknown>:0 at Hyena.Data.Sqlite.Connection.Execute (System.String sql) [0x00000] in <filename unknown>:0 at Hyena.Data.Sqlite.HyenaSqliteCommand.Execute (Hyena.Data.Sqlite.HyenaSqliteConnection hconnection, Hyena.Data.Sqlite.Connection connection) [0x00000] in <filename unknown>:0 Exception has been thrown by the target of an invocation. at System.Reflection.MonoCMethod.Invoke (System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) [0x00000] in <filename unknown>:0 at System.Reflection.MonoCMethod.Invoke (BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) [0x00000] in <filename unknown>:0 at System.Reflection.ConstructorInfo.Invoke (System.Object[] parameters) [0x00000] in <filename unknown>:0 at System.Activator.CreateInstance (System.Type type, Boolean nonPublic) [0x00000] in <filename unknown>:0 at System.Activator.CreateInstance (System.Type type) [0x00000] in <filename unknown>:0 at Banshee.Gui.GtkBaseClient.Startup () [0x00000] in <filename unknown>:0 at Hyena.Gui.CleanRoomStartup.Startup (Hyena.Gui.StartupInvocationHandler startup) [0x00000] in <filename unknown>:0 .NET Version: 2.0.50727.1433 OS Version: Unix 2.6.35.27 Assembly Version Information: gkeyfile-sharp (1.0.0.0) Banshee.AudioCd (1.9.0.0) Banshee.MiniMode (1.9.0.0) Banshee.CoverArt (1.9.0.0) indicate-sharp (0.4.1.0) notify-sharp (0.4.0.0) Banshee.SoundMenu (1.9.0.0) Banshee.Mpris (1.9.0.0) Migo (1.9.0.0) Banshee.Podcasting (1.9.0.0) Banshee.Dap (1.9.0.0) Banshee.LibraryWatcher (1.9.0.0) Banshee.MultimediaKeys (1.9.0.0) Banshee.Bpm (1.9.0.0) Banshee.YouTube (1.9.0.0) Banshee.WebBrowser (1.9.0.0) Banshee.Wikipedia (1.9.0.0) pango-sharp (2.12.0.0) Banshee.Fixup (1.9.0.0) Banshee.Widgets (1.9.0.0) gio-sharp (2.14.0.0) gudev-sharp (1.0.0.0) Banshee.Gio (1.9.0.0) Banshee.GStreamer (1.9.0.0) System.Configuration (2.0.0.0) NDesk.DBus.GLib (1.0.0.0) gconf-sharp (2.24.0.0) Banshee.Gnome (1.9.0.0) Banshee.NowPlaying (1.9.0.0) Mono.Cairo (2.0.0.0) System.Xml (2.0.0.0) Banshee.Core (1.9.0.0) Hyena.Data.Sqlite (1.9.0.0) System.Core (3.5.0.0) gdk-sharp (2.12.0.0) Mono.Addins (0.4.0.0) atk-sharp (2.12.0.0) Hyena.Gui (1.9.0.0) gtk-sharp (2.12.0.0) Banshee.ThickClient (1.9.0.0) Nereid (1.9.0.0) NDesk.DBus.Proxies (0.0.0.0) Mono.Posix (2.0.0.0) NDesk.DBus (1.0.0.0) glib-sharp (2.12.0.0) Hyena (1.9.0.0) System (2.0.0.0) Banshee.Services (1.9.0.0) Banshee (1.9.0.0) mscorlib (2.0.0.0) Platform Information: Linux 2.6.35-27-generic i686 unknown GNU/Linux Disribution Information: [/etc/lsb-release] DISTRIB_ID=Ubuntu DISTRIB_RELEASE=10.10 DISTRIB_CODENAME=maverick DISTRIB_DESCRIPTION="Ubuntu 10.10" [/etc/debian_version] squeeze/sid Just to make it clear, this happened only after the hard resets and not before. I used to use banshee everyday and it worked perfectly. Can anyone help me fix this?

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  • Ubuntu 11.04 and 10.04 hang with black screen while installing from USB disk

    - by Bill
    I've been trying to install Ubuntu 11.04 from a USB flash stick and each time I try to boot from the USB key one of two things happen: A) The screen that asks you what you would like to do (e.g. run Ubuntu from the USB key or install it) shows up and the countdown to the default option starts to count down but as soon as I either touch the keyboard (sometimes I press enter or the arrow keys to select an option) or the countdown gets to zero the screen just locks up and nothing happens no matter how long I wait. B) When I boot from the USB key the screen will flicker for a second and then go black with a flashing white underscore at the top left corner of the screen. Again it doesn't matter how long I wait, nothing happens and pressing keys doesn't do a thing. The very first time I tried to install it I got a terminal-like screen that said something about a directory called 'casper' having an error of some sort. I have tried installing from USB using both 11.04 and 10.10. I'm about to try 10.04. I have read tons of forum posts about this but so far I haven't seen anything in the solutions that apply to me. My intention is to dual boot Windows 7 and Ubuntu. I must keep Windows as I am required to use Visual Studio for one of my college courses. Right now I'm using Wubi but I really want a full install. I can't use LVPM because it doesn't work with the version of Wubi I used. So now I'm thinking my best bet is to try to get a clean install working. I'd also convert Wubi to a full install too but there's no solution as far as I've read. So could someone tell me a reason why this is happening or if there's something I can do to get around the problem? I'm using a Gateway LT2802u netbook with and Intel Atom N455 processor, 1GB RAM, Intel Graphics Media Accelerator 3150 graphics card, and a 250GB HDD. I don't have anything on my current Wubi install that I can't replace so keep in mind when answering that I don't care if I lose my current settings and files from Wubi. Thanks everyone! UPDATE I just answered my own question so in case anyone else is having this same problem using similar hardware, do the following: When I first tried installing 11.04 I used the recommended universal installer tool to create the USB live/installation disk. That caused the original problem. Note that I had already downloaded the 11.04 ISO and did not use the included downloader from the USB creator. After that failed I used the same USB creator but had it download 10.10 for me. It also failed with the same issue. I repeated this process with unetbootin as well for both versions. Finally, I downloaded the Ubuntu 10.04 ISO and used the recommended USB creator once again. There was an error while creating the USB live install so I reformatted the USB key as FAT32 and tried again. It created the USB key. I then booted from the USB flash drive and selected "Install Ubuntu" (exact wording was different). It worked! It took me through the process that you see shown in pictures on the Ubuntu website. I let it create the appropriate partitions for me and it simply worked. I did get a few errors while the system tried to restart after it installed. It hung on a terminal-like screen but I pressed ENTER and it restarted. I booted into Windows 7, it checked the disks as it sensed that I messed with a partition, then it booted into Windows normally. Now I'm going to uninstall Wubi and update my new full install of Ubuntu! I'm excited to get the benefits of a full install now. So in the end, hopefully someone can learn from what I did.

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  • How to Get All the Windows 8 Editions on One Install Disk

    - by Taylor Gibb
    There are a lot of different versions of Windows, but you probably didn’t know that short of the Enterprise edition, the disc or image that you own contains all versions for that architecture. Read on to see how we can use them to make a universal Windows 8 install disc. Things You Will Need A x86 Version of Windows 8 A x64 Version of Windows 8 A x86 Version of Windows 8 Enterprise A x64 Version of Windows 8 Enterprise A Windows 8 PC Note: While we will use all the images above you don’t really need the Enterprise Edition. You could always leave out parts of the tutorial if you know what you are doing, if you are not comfortable with that and still want to follow through you could always grab the Enterprise evaluation images that are available for free to the public, on MSDN. Getting Started To get started you will need to Download the Windows 8 ADK from Microsoft. Once downloaded go ahead and install it, you will only need the Deployment tools so be sure to uncheck the rest of the options. Lastly you will also need to create the following folder structure on the root of your C:\ drive to make things a bit easier. C:\Windows8Root C:\Windows8Root\x86 C:\Windows8Root\x64 C:\Windows8Root\Enterprisex86 C:\Windows8Root\Enterprisex64 C:\Windows8Root\Temp C:\Windows8Root\Final OK lets get started. Making The Image The first thing we need to do is create a base image, so mount the x86 version of Windows 8 and copy its files to: C:\Windows8Root\Final Now move the install.wim file from: C:\Windows8Root\Final\sources To: C:\Windows8Root\x86 Next go ahead and copy the install.wim file from the other 3 images, Windows 8 x64, Windows 8 Enterprise x86 and Windows 8 Enterprise x64 to the respective folders in Windows8Root, the install.wim file can be located at: D:\sources\install.wim Note: The above assumes that the images are always mounted at drive D. Remember that each install.wim is different so don’t copy them to the wrong directories or the rest of the tutorial wont work. Next switch to the Metro Start Screen and open the Deployment and Imaging Tools Environment. Note: If you are not a local administrator on your PC, you will need to right-click on it and choose to run it as an administrator. Now run the following commands: Dism /Export-Image /SourceImageFile:c:\Windows8Root\x86\install.wim /SourceIndex:2 /DestinationImageFile:c:\Windows8Root\Final\sources\install.wim /DestinationName:”Windows 8″ /compress:maximum Dism /Export-Image /SourceImageFile:c:\Windows8Root\x86\install.wim /SourceIndex:1 /DestinationImageFile:c:\Windows8Root\Final\sources\install.wim /DestinationName:”Windows 8 Pro” /compress:maximum Dism /Export-Image /SourceImageFile:c:\Windows8Root\x86\install.wim /SourceIndex:1 /DestinationImageFile:c:\Windows8Root\Final\sources\install.wim /DestinationName:”Windows 8 Pro with Media Center” /compress:maximum Dism /Export-Image /SourceImageFile:c:\Windows8Root\Enterprisex86\install.wim /SourceIndex:1 /DestinationImageFile:c:\Windows8Root\Final\sources\install.wim /DestinationName:”Windows 8 Enterprise” /compress:maximum Dism /Export-Image /SourceImageFile:c:\Windows8Root\x64\install.wim /SourceIndex:2 /DestinationImageFile:c:\Windows8Root\Final\sources\install.wim /DestinationName:”Windows 8″ /compress:maximum Dism /Export-Image /SourceImageFile:c:\Windows8Root\x64\install.wim /SourceIndex:1 /DestinationImageFile:c:\Windows8Root\Final\sources\install.wim /DestinationName:”Windows 8 Pro” /compress:maximum Dism /Export-Image /SourceImageFile:c:\Windows8Root\x64\install.wim /SourceIndex:1 /DestinationImageFile:c:\Windows8Root\Final\sources\install.wim /DestinationName:”Windows 8 Pro with Media Center” /compress:maximum Dism /Export-Image /SourceImageFile:c:\Windows8Root\Enterprisex64\install.wim /SourceIndex:1 /DestinationImageFile:c:\Windows8Root\Final\sources\install.wim /DestinationName:”Windows 8 Enterprise” /compress:maximum Next navigate to: C:\Windows8Root\sources\ And create a new text file. You will need to call it: EI.cfg Then edit it to look like the following: The last thing we need to do is work some magic to get Windows Media Center added to the WMC editions of Windows 8. For that I have written a little script to make it easier for everybody, you can grab it here. Once you have downloaded it extract it. In order to use it right-click in the bottom left hand corner of the screen, and open an elevated command prompt. Then go ahead and paste the following into the command prompt window. powershell.exe -ExecutionPolicy Unrestricted -File C:\Users\Taylor\Documents\HTGWindows8Converter.ps1 Note: You will need to replace the path to the script, another thing to note is that if the path you replace it with has spaces you will need to enclose the path in quotes. The script should kick off straight away and has some progress bars you can watch while it does its thing. Half way through another Window will pop open, which will start creating your final ISO image. When its complete, close the command prompt and you should have an ISO image on the root of your C drive called: HTGWindows8.iso That’s all there is to it. 7 Ways To Free Up Hard Disk Space On Windows HTG Explains: How System Restore Works in Windows HTG Explains: How Antivirus Software Works

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  • Still about SSD potentials...write and read speed

    - by Macroideal
    I have been working on SSD (solid state disk) for several months..Problems and Questions hit my head unexpectedly..Coz i am a virgin in ssd... Especially these days I was testing the write-read speed of ssd, which I was always caring.... however result turned out not good as I expected, or even worse Three kinds of read-write were implemented in my test read and write directly from and into ssd, with openning ssd as a whole device. in windows: _open("\\:g", ***).. It can be very tricky and hairy that you'd write a data with size of folds of 512, at the disk position of folds of 512bytes... So, If you wanto write just a byte or 4 bytes, you'v to write at least a whole sector one time. Read and write data from and into files located in SSD... Read and Write data from and into files in mechanical Disk I compared the pratices below...I found ssd sucks...the ssd performs worse than mechanical disk... so i am wondering where i can get the potential performance of ssd, since ssd is said to a substitute for mechanical disk in the future.. Nevertheless, I test ssd with a pro-hard-disk tools..ssd is like twice speedier than mechanical disk. So, why?

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  • Can't mount Linux usd disk. It just create /dev/sg device but no /dev/sd

    - by MTilsted
    I have a Corsair R60 ssd disk which is a disk with both sata and usb connectors. But the usb thing seems to be a bit non-standard, or maybe its just my fedora linux. When I insert the disk using a usb cabel to a running Fedora 14 linux system, a device called /dev/sg3 is added but that is all. No new /dev/sd* device is created so I can't mount the disk. If I look at cat /proc/scsi/sg/device_strs I get ATA Hitachi HTS54321 FB2O HL-DT-ST DVDRAM GSA-T50N RP05 Seagate Desktop 0130 Corsair CSSD-R60GB2 So the disk is there. (The last entry) but my linux will for some reason not see it as a usb hard disk. When I insert other usb disks they work fine. It is only this specific disk which causes problems. I have tried on 3 different computers with the same result. A hint to the problem may be that if I add the disk to a windows system(With usb) the disk is called "A fixed disk" and not a portable disk as expected. The disk works fine with linux If i connect it with the sata cabel, but I would really like to have it working with usb too. (To mount it on computers without sata).

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  • Can't mount Linux usb disk. It just create /dev/sg device but no /dev/sd

    - by MTilsted
    I have a Corsair R60 ssd disk which is a disk with both sata and usb connectors. But the usb thing seems to be a bit non-standard, or maybe its just my fedora linux. When I insert the disk using a usb cabel to a running Fedora 14 linux system, a device called /dev/sg3 is added but that is all. No new /dev/sd* device is created so I can't mount the disk. If I look at cat /proc/scsi/sg/device_strs I get ATA Hitachi HTS54321 FB2O HL-DT-ST DVDRAM GSA-T50N RP05 Seagate Desktop 0130 Corsair CSSD-R60GB2 So the disk is there. (The last entry) but my linux will for some reason not see it as a usb hard disk. When I insert other usb disks they work fine. It is only this specific disk which causes problems. I have tried on 3 different computers with the same result. A hint to the problem may be that if I add the disk to a windows system(With usb) the disk is called "A fixed disk" and not a portable disk as expected. The disk works fine with linux If i connect it with the sata cabel, but I would really like to have it working with usb too. (To mount it on computers without sata). Added: I did try to mount /dev/sg3 but mount say that its not a block device. (File say Its a character special device). Added output from dmesg: [ 97.454073] usb 7-1: USB disconnect, address 2 [ 105.913055] hub 2-0:1.0: unable to enumerate USB device on port 3 [ 107.048054] usb 2-3: new high speed USB device using ehci_hcd and address 5 [ 107.162900] usb 2-3: New USB device found, idVendor=1b1c, idProduct=1ab8 [ 107.162903] usb 2-3: New USB device strings: Mfr=1, Product=2, SerialNumber=5 [ 107.162906] usb 2-3: Product: CSSD-R60GB2 [ 107.162908] usb 2-3: Manufacturer: Corsair [ 107.162910] usb 2-3: SerialNumber: 10111441000000990069 [ 107.167651] scsi7 : usb-storage 2-3:1.0 [ 108.195543] scsi 7:0:0:0: Direct-Access Corsair CSSD-R60GB2 PQ: 1 ANSI: 0 [ 108.197732] scsi 7:0:0:0: Attached scsi generic sg3 type 0

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  • Is there a Mac utility that does low level drive integrity check and repair?

    - by Puzzled Late at Night
    The PGP Whole Disk Encryption for Mac OS X Quick Start User Guide version 10.0 contains the following remarks: PGP Corporation deliberately takes a conservative stance when encrypting drives, to prevent loss of data. It is not uncommon to encounter Cyclic Redundancy Check (CRC) errors while encrypting a hard disk. If PGP WDE encounters a hard drive with bad sectors, PGP WDE will, by default, pause the encryption process. This pause allows you to remedy the problem before continuing with the encryption process, thus avoiding potential disk corruption and lost data. To avoid disruption during encryption, PGP Corporation recommends that you start with a healthy disk by correcting any disk errors prior to encrypting. and As a best practice, before you attempt to use PGP WDE, use a third-party scan disk utility that has the ability to perform a low-level integrity check and repair any inconsistencies with the drive that could lead to CRC errors. These software applications can correct errors that would otherwise disrupt encryption. The PGP WDE Windows user guide suggests SpinRite or Norton Disk Doctor. What recourse do I have on the Mac?

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  • Where's my free space gone? (on my mac) [closed]

    - by Cawas
    Possible Duplicate: Something’s slowly eating my HD space Somehow part of my files from my USB disk, 40GB of it (exactly the space I was missing), were copied to /Volumes/ and when I mounted the disk it was called "600GB Disk 2", while "600GB Disk" was filled with duplicated data. All that happened at once, slowly, just this morning when I turned on my macbook. I could notice that thanks to Disk Inventory X. I could actually see those on GrandPerspective, but I thought it was just scanning my USB limited to that folder for whatever reason. On Disk Inventory I could see the /Volumes/ listing one folder as a folder and the second one as a link, like it should be. Well, looking at that folder, I quickly associated what was in it with my scheduled backup on Carbon Copy Cloner. I'm still not sure why the USB disk was mounted with wrong name, but what happened was CCC store the full path information of the source and destination, so when it tried to do the schedule backup it created the path that didn't exist, and copied everything there - while it should be copying into the mounted volume. While this is solved this time, what else could I have done to diagnose this kind of issue, for the next time?

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  • Do fluent interfaces significantly impact runtime performance of a .NET application?

    - by stakx
    I'm currently occupying myself with implementing a fluent interface for an existing technology, which would allow code similar to the following snippet: using (var directory = Open.Directory(@"path\to\some\directory")) { using (var file = Open.File("foobar.html").In(directory)) { // ... } } In order to implement such constructs, classes are needed that accumulate arguments and pass them on to other objects. For example, to implement the Open.File(...).In(...) construct, you would need two classes: // handles 'Open.XXX': public static class OpenPhrase { // handles 'Open.File(XXX)': public static OpenFilePhrase File(string filename) { return new OpenFilePhrase(filename); } // handles 'Open.Directory(XXX)': public static DirectoryObject Directory(string path) { // ... } } // handles 'Open.File(XXX).XXX': public class OpenFilePhrase { internal OpenFilePhrase(string filename) { _filename = filename } // handles 'Open.File(XXX).In(XXX): public FileObject In(DirectoryObject directory) { // ... } private readonly string _filename; } That is, the more constituent parts statements such as the initial examples have, the more objects need to be created for passing on arguments to subsequent objects in the chain until the actual statement can finally execute. Question: I am interested in some opinions: Does a fluent interface which is implemented using the above technique significantly impact the runtime performance of an application that uses it? With runtime performance, I refer to both speed and memory usage aspects. Bear in mind that a potentially large number of temporary, argument-saving objects would have to be created for only very brief timespans, which I assume may put a certain pressure on the garbage collector. If you think there is significant performance impact, do you know of a better way to implement fluent interfaces?

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  • How do I track down sporadic ASP.NET performance problems in a production environment?

    - by Steve Wortham
    I've had sporadic performance problems with my website for awhile now. 90% of the time the site is very fast. But occasionally it is just really, really slow. I mean like 5-10 seconds load time kind of slow. I thought I had narrowed it down to the server I was on so I migrated everything to a new dedicated server from a completely different web hosting company. But the problems continue. I guess what I'm looking for is a good tool that'll help me track down the problem, because it's clearly not the hardware. I'd like to be able to log certain events in my ASP.NET code and have that same logger also track server performance/resources at the time. If I can then look back at the logs then I can see what exactly my website was doing at the time of extreme slowness. Is there a .NET logging system that'll allow me to make calls into it with code while simultaneously tracking performance? What would you recommend?

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  • How do I improve my performance with this singly linked list struct within my program?

    - by Jesus
    Hey guys, I have a program that does operations of sets of strings. We have to implement functions such as addition and subtraction of two sets of strings. We are suppose to get it down to the point where performance if of O(N+M), where N,M are sets of strings. Right now, I believe my performance is at O(N*M), since I for each element of N, I go through every element of M. I'm particularly focused on getting the subtraction to the proper performance, as if I can get that down to proper performance, I believe I can carry that knowledge over to the rest of things I have to implement. The '-' operator is suppose to work like this, for example. Declare set1 to be an empty set. Declare set2 to be a set with { a b c } elements Declare set3 to be a set with ( b c d } elements set1 = set2 - set3 And now set1 is suppose to equal { a }. So basically, just remove any element from set3, that is also in set2. For the addition implementation (overloaded '+' operator), I also do the sorting of the strings (since we have to). All the functions work right now btw. So I was wondering if anyone could a) Confirm that currently I'm doing O(N*M) performance b) Give me some ideas/implementations on how to improve the performance to O(N+M) Note: I cannot add any member variables or functions to the class strSet or to the node structure. The implementation of the main program isn't very important, but I will post the code for my class definition and the implementation of the member functions: strSet2.h (Implementation of my class and struct) // Class to implement sets of strings // Implements operators for union, intersection, subtraction, // etc. for sets of strings // V1.1 15 Feb 2011 Added guard (#ifndef), deleted using namespace RCH #ifndef _STRSET_ #define _STRSET_ #include <iostream> #include <vector> #include <string> // Deleted: using namespace std; 15 Feb 2011 RCH struct node { std::string s1; node * next; }; class strSet { private: node * first; public: strSet (); // Create empty set strSet (std::string s); // Create singleton set strSet (const strSet &copy); // Copy constructor ~strSet (); // Destructor int SIZE() const; bool isMember (std::string s) const; strSet operator + (const strSet& rtSide); // Union strSet operator - (const strSet& rtSide); // Set subtraction strSet& operator = (const strSet& rtSide); // Assignment }; // End of strSet class #endif // _STRSET_ strSet2.cpp (implementation of member functions) #include <iostream> #include <vector> #include <string> #include "strset2.h" using namespace std; strSet::strSet() { first = NULL; } strSet::strSet(string s) { node *temp; temp = new node; temp->s1 = s; temp->next = NULL; first = temp; } strSet::strSet(const strSet& copy) { if(copy.first == NULL) { first = NULL; } else { node *n = copy.first; node *prev = NULL; while (n) { node *newNode = new node; newNode->s1 = n->s1; newNode->next = NULL; if (prev) { prev->next = newNode; } else { first = newNode; } prev = newNode; n = n->next; } } } strSet::~strSet() { if(first != NULL) { while(first->next != NULL) { node *nextNode = first->next; first->next = nextNode->next; delete nextNode; } } } int strSet::SIZE() const { int size = 0; node *temp = first; while(temp!=NULL) { size++; temp=temp->next; } return size; } bool strSet::isMember(string s) const { node *temp = first; while(temp != NULL) { if(temp->s1 == s) { return true; } temp = temp->next; } return false; } strSet strSet::operator + (const strSet& rtSide) { strSet newSet; newSet = *this; node *temp = rtSide.first; while(temp != NULL) { string newEle = temp->s1; if(!isMember(newEle)) { if(newSet.first==NULL) { node *newNode; newNode = new node; newNode->s1 = newEle; newNode->next = NULL; newSet.first = newNode; } else if(newSet.SIZE() == 1) { if(newEle < newSet.first->s1) { node *tempNext = newSet.first; node *newNode; newNode = new node; newNode->s1 = newEle; newNode->next = tempNext; newSet.first = newNode; } else { node *newNode; newNode = new node; newNode->s1 = newEle; newNode->next = NULL; newSet.first->next = newNode; } } else { node *prev = NULL; node *curr = newSet.first; while(curr != NULL) { if(newEle < curr->s1) { if(prev == NULL) { node *newNode; newNode = new node; newNode->s1 = newEle; newNode->next = curr; newSet.first = newNode; break; } else { node *newNode; newNode = new node; newNode->s1 = newEle; newNode->next = curr; prev->next = newNode; break; } } if(curr->next == NULL) { node *newNode; newNode = new node; newNode->s1 = newEle; newNode->next = NULL; curr->next = newNode; break; } prev = curr; curr = curr->next; } } } temp = temp->next; } return newSet; } strSet strSet::operator - (const strSet& rtSide) { strSet newSet; newSet = *this; node *temp = rtSide.first; while(temp != NULL) { string element = temp->s1; node *prev = NULL; node *curr = newSet.first; while(curr != NULL) { if( element < curr->s1 ) break; if( curr->s1 == element ) { if( prev == NULL) { node *duplicate = curr; newSet.first = newSet.first->next; delete duplicate; break; } else { node *duplicate = curr; prev->next = curr->next; delete duplicate; break; } } prev = curr; curr = curr->next; } temp = temp->next; } return newSet; } strSet& strSet::operator = (const strSet& rtSide) { if(this != &rtSide) { if(first != NULL) { while(first->next != NULL) { node *nextNode = first->next; first->next = nextNode->next; delete nextNode; } } if(rtSide.first == NULL) { first = NULL; } else { node *n = rtSide.first; node *prev = NULL; while (n) { node *newNode = new node; newNode->s1 = n->s1; newNode->next = NULL; if (prev) { prev->next = newNode; } else { first = newNode; } prev = newNode; n = n->next; } } } return *this; }

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  • The best way to predict performance without actually porting the code?

    - by ardiyu07
    I believe there are people with the same experience with me, where he/she must give a (estimated) performance report of porting a program from sequential to parallel with some designated multicore hardwares, with a very few amount of time given. For instance, if a 10K LoC sequential program was given and executes on Intel i7-3770k (not vectorized) in 100 ms, how long would it take to run if one parallelizes the code to a Tesla C2075 with NVIDIA CUDA, given that all kinds of parallelizing optimization techniques were done? (but you're only given 2-4 days to report the performance? assume that you didn't know the algorithm at all. Or perhaps it'd be safer if we just assume that it's an impossible situation to finish the job) Therefore, I'm wondering, what most likely be the fastest way to give such performance report? Is it safe to calculate solely by the hardware's capability, such as GFLOPs peak and memory bandwidth rate? Is there a mathematical way to calculate it? If there is, please prove your method with the corresponding problem description and the algorithm, and also the target hardwares' specifications. Or perhaps there already exists such tool to (roughly) estimate code porting? (Please don't the answer: 'kill yourself is the fastest way.')

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  • SQL SERVER – Subquery or Join – Various Options – SQL Server Engine knows the Best

    - by pinaldave
    This is followup post of my earlier article SQL SERVER – Convert IN to EXISTS – Performance Talk, after reading all the comments I have received I felt that I could write more on the same subject to clear few things out. First let us run following four queries, all of them are giving exactly same resultset. USE AdventureWorks GO -- use of = SELECT * FROM HumanResources.Employee E WHERE E.EmployeeID = ( SELECT EA.EmployeeID FROM HumanResources.EmployeeAddress EA WHERE EA.EmployeeID = E.EmployeeID) GO -- use of in SELECT * FROM HumanResources.Employee E WHERE E.EmployeeID IN ( SELECT EA.EmployeeID FROM HumanResources.EmployeeAddress EA WHERE EA.EmployeeID = E.EmployeeID) GO -- use of exists SELECT * FROM HumanResources.Employee E WHERE EXISTS ( SELECT EA.EmployeeID FROM HumanResources.EmployeeAddress EA WHERE EA.EmployeeID = E.EmployeeID) GO -- Use of Join SELECT * FROM HumanResources.Employee E INNER JOIN HumanResources.EmployeeAddress EA ON E.EmployeeID = EA.EmployeeID GO Let us compare the execution plan of the queries listed above. Click on image to see larger image. It is quite clear from the execution plan that in case of IN, EXISTS and JOIN SQL Server Engines is smart enough to figure out what is the best optimal plan of Merge Join for the same query and execute the same. However, in the case of use of Equal (=) Operator, SQL Server is forced to use Nested Loop and test each result of the inner query and compare to outer query, leading to cut the performance. Please note that here I no mean suggesting that Nested Loop is bad or Merge Join is better. This can very well vary on your machine and amount of resources available on your computer. When I see Equal (=) operator used in query like above, I usually recommend to see if user can use IN or EXISTS or JOIN. As I said, this can very much vary on different system. What is your take in above query? I believe SQL Server Engines is usually pretty smart to figure out what is ideal execution plan and use it. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Joins, SQL Optimization, SQL Performance, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • SQL SERVER – Server Side Paging in SQL Server 2011 – Part2

    - by pinaldave
    The best part of the having blog is that SQL Community helps to keep it running with new ideas. Earlier I wrote about SQL SERVER – Server Side Paging in SQL Server 2011 – A Better Alternative. A very popular article on that subject. I had used variables for “number of the rows” and “number of the pages”. Blog reader send me email asking in their organizations these values are stored in the table. Is there any the new syntax can read the data from the table. Absolutely YES! USE AdventureWorks2008R2 GO CREATE TABLE PagingSetting (RowsPerPage INT, PageNumber INT) INSERT INTO PagingSetting (RowsPerPage, PageNumber) VALUES(10,5) GO SELECT * FROM Sales.SalesOrderDetail ORDER BY SalesOrderDetailID OFFSET (SELECT RowsPerPage*PageNumber FROM PagingSetting) ROWS FETCH NEXT (SELECT RowsPerPage FROM PagingSetting) ROWS ONLY GO Here is the quick script: This is really an easy trick. I also wrote blog post on comparison of the performance over here: . SQL SERVER – Server Side Paging in SQL Server 2011 Performance Comparison Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Performance, SQL Query, SQL Scripts, SQL Server, SQL Tips and Tricks, SQLServer, T SQL, Technology Tagged: SQL Paging

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  • SQLAuthority News – Public Training Classes In Hyderabad 12-14 May – SQL and 10-11 May SharePoint

    - by pinaldave
    There were lots of request about providing more details for the blog post through email address specified in the article SQLAuthority News – Public Training Classes In Hyderabad 12-14 May – Microsoft SQL Server 2005/2008 Query Optimization & Performance Tuning. Here is the complete brochure of the course. There are two different courses are offered by Solid Quality Mentors 1) Microsoft SQL Server 2005/2008 Query Optimization & Performance Tuning – Pinal Dave Date: May 12-14, 2010 Price: Rs. 14,000/person for 3 days Discount Code: ‘SQLAuthority.com‘ Effective Price: Rs. 11,000/person for 3 days 2) SharePoint 2010 – Joy Rathnayake Date: May 10-11, 2010 Price: Rs. 11,000/person for 3 days Discount Code: ‘SQLAuthority.com’ Effective Price: Rs. 8,000/person for 3 days Download the complete PDF brochure. Additionally there is special program of SolidQ India Insider. I will provide the details for the same very soon. Please do send me email if you need any additional details. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Optimization, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, SQL Training, SQLAuthority News, T SQL, Technology

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  • Oracle Linux Delivers Top CPU Benchmark Results on Sun Blades

    - by sergio.leunissen
    From the Performance and Best Practices blog: Fresh SPEC CPU2006 results for Sun Blade X6275 M2 Server Modules running Oracle Linux 5.5. The highlights: The dual-node Sun Blade X6275 M2 server module, equipped with two Intel Xeon X5670 2.93 GHz processors per node and running the Oracle Enterprise Linux 5.5 operating system delivered the best SPECint_rate2006 and SPECfp_rate2006 benchmark results for all systems with Intel Xeon processor 5000 sequence. With a SPECint_rate2006 benchmark result of 679, the Sun Blade X6275 M2 server module, with two compute nodes per blade, delivers maximum performance for space constrained environments. Comparing Oracle's dual-node blade to HP's dual-node blade server, based on their single node performance, the Sun Blade X6275 M2 server module SPECfp_rate2006 score of 241 outperforms the best published HP ProLiant BL2X220c G5 server score by 3.2x. A single node of a Sun Blade X6275 M2 server module using 2.93 GHz Intel Xeon X5670 processors delivered 37% improvement in SPECint_rate2006 benchmark results and 22% improvement in SPECfp_rate2006 benchmark results compared to the previous generation Sun Blade X6275 server module. Both nodes of a Sun Blade X6275 M2 server module using 2.93 GHz Intel Xeon X5670 processors delivered 59% improvement on the SPECint_rate2006 benchmark and 40% improvement on the SPECfp_rate2006 benchmark compared to the previous generation Sun Blade X6275 server module.

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  • SQLAuthority News – Public Training Classes In Hyderabad 12-14 May – SQL and 10-11 May SharePoint

    - by pinaldave
    There were lots of request about providing more details for the blog post through email address specified in the article SQLAuthority News – Public Training Classes In Hyderabad 12-14 May – Microsoft SQL Server 2005/2008 Query Optimization & Performance Tuning. Here is the complete brochure of the course. There are two different courses are offered by Solid Quality Mentors 1) Microsoft SQL Server 2005/2008 Query Optimization & Performance Tuning – Pinal Dave Date: May 12-14, 2010 Price: Rs. 14,000/person for 3 days Discount Code: ‘SQLAuthority.com‘ Effective Price: Rs. 11,000/person for 3 days 2) SharePoint 2010 – Joy Rathnayake Date: May 10-11, 2010 Price: Rs. 11,000/person for 3 days Discount Code: ‘SQLAuthority.com’ Effective Price: Rs. 8,000/person for 3 days Download the complete PDF brochure. Additionally there is special program of SolidQ India Insider. I will provide the details for the same very soon. Please do send me email if you need any additional details. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Optimization, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, SQL Training, SQLAuthority News, T SQL, Technology

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  • SQL SERVER – GUID vs INT – Your Opinion

    - by pinaldave
    I think the title is clear what I am going to write in your post. This is age old problem and I want to compile the list stating advantages and disadvantages of using GUID and INT as a Primary Key or Clustered Index or Both (the usual case). Let me start a list by suggesting one advantage and one disadvantage in each case. INT Advantage: Numeric values (and specifically integers) are better for performance when used in joins, indexes and conditions. Numeric values are easier to understand for application users if they are displayed. Disadvantage: If your table is large, it is quite possible it will run out of it and after some numeric value there will be no additional identity to use. GUID Advantage: Unique across the server. Disadvantage: String values are not as optimal as integer values for performance when used in joins, indexes and conditions. More storage space is required than INT. Please note that I am looking to create list of all the generic comparisons. There can be special cases where the stated information is incorrect, feel free to comment on the same. Please leave your opinion and advice in comment section. I will combine a final list and update this blog after a week. By listing your name in post, I will also give due credit. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, SQL, SQL Authority, SQL Constraint and Keys, SQL Data Storage, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, SQLServer, T SQL, Technology

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  • How can I create a 4TB partition on my software RAID5 device?

    - by Kris Harper
    I have set up a RAID5 device with three 2TB hard drives using mdadm. The device was successfully created, but I cannot seem to create a partition on the device. When I try to make an ext3 or ext4 partition via Disk Utility, I get the following error Error creating partition: helper exited with exit code 1: In part_add_partition: device_file=/dev/md0, start=0, size=4000526106624, type= Entering MS-DOS parser (offset=0, size=4000526106624) MSDOS_MAGIC found found partition type 0xee => protective MBR for GPT Exiting MS-DOS parser Entering EFI GPT parser GPT magic found partition_entry_lba=2 num_entries=128 size_of_entry=128 Leaving EFI GPT parser EFI GPT partition table detected containing partition table scheme = 3 got it got disk new partition guid '' is not valid type '' for GPT appear to be malformed I have seen this question, but that seems to suggest using gparted to do the partitioning. I'm fine with doing that, but my RAID device doesn't show up in the list of gparted devices. I suspect because this is a RAID and not a regular disk. I have already created a GPT partition table on the device. How can I add a partition to my device?

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  • SQL SERVER – Cleaning Up SQL Server Indexes – Defragmentation, Fillfactor – Video

    - by pinaldave
    Storing data non-contiguously on disk is known as fragmentation. Before learning to eliminate fragmentation, you should have a clear understanding of the types of fragmentation. When records are stored non-contiguously inside the page, then it is called internal fragmentation. When on disk, the physical storage of pages and extents is not contiguous. We can get both types of fragmentation using the DMV: sys.dm_db_index_physical_stats. Here is the generic advice for reducing the fragmentation. If avg_fragmentation_in_percent > 5% and < 30%, then use ALTER INDEX REORGANIZE: This statement is replacement for DBCC INDEXDEFRAG to reorder the leaf level pages of the index in a logical order. As this is an online operation, the index is available while the statement is running. If avg_fragmentation_in_percent > 30%, then use ALTER INDEX REBUILD: This is replacement for DBCC DBREINDEX to rebuild the index online or offline. In such case, we can also use the drop and re-create index method.(Ref: MSDN) Here is quick video which covers many of the above mentioned topics. While Vinod and I were planning about Indexing course, we had plenty of fun and learning. We often recording few of our statement and just left it aside. Afterwords we thought it will be really funny Here is funny video shot by Vinod and Myself on the same subject: Here is the link to the SQL Server Performance:  Indexing Basics. Here is the additional reading material on the same subject: SQL SERVER – Fragmentation – Detect Fragmentation and Eliminate Fragmentation SQL SERVER – 2005 – Display Fragmentation Information of Data and Indexes of Database Table SQL SERVER – De-fragmentation of Database at Operating System to Improve Performance Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Index, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology, Video

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  • The enterprise vendor con - connecting SSD's using SATA 2 (3Gbits) thus limiting there performance

    - by tonyrogerson
    When comparing SSD against Hard drive performance it really makes me cross when folk think comparing an array of SSD running on 3GBits/sec to hard drives running on 6GBits/second is somehow valid. In a paper from DELL (http://www.dell.com/downloads/global/products/pvaul/en/PowerEdge-PowerVaultH800-CacheCade-final.pdf) on increasing database performance using the DELL PERC H800 with Solid State Drives they compare four SSD drives connected at 3Gbits/sec against ten 10Krpm drives connected at 6Gbits [Tony slaps forehead while shouting DOH!]. It is true in the case of hard drives it probably doesn’t make much difference 3Gbit or 6Gbit because SAS and SATA are both end to end protocols rather than shared bus architecture like SCSI, so the hard drive doesn’t share bandwidth and probably can’t get near the 600MiBytes/second throughput that 6Gbit gives unless you are doing contiguous reads, in my own tests on a single 15Krpm SAS disk using IOMeter (8 worker threads, queue depth of 16 with a stripe size of 64KiB, an 8KiB transfer size on a drive formatted with an allocation size of 8KiB for a 100% sequential read test) I only get 347MiBytes per second sustained throughput at an average latency of 2.87ms per IO equating to 44.5K IOps, ok, if that was 3GBits it would be less – around 280MiBytes per second, oh, but wait a minute [...fingers tap desk] You’ll struggle to find in the commodity space an SSD that doesn’t have the SATA 3 (6GBits) interface, SSD’s are fast not only low latency and high IOps but they also offer a very large sustained transfer rate, consider the OCZ Agility 3 it so happens that in my masters dissertation I did the same test but on a difference box, I got 374MiBytes per second at an average latency of 2.67ms per IO equating to 47.9K IOps – cost of an 240GB Agility 3 is £174.24 (http://www.scan.co.uk/products/240gb-ocz-agility-3-ssd-25-sata-6gb-s-sandforce-2281-read-525mb-s-write-500mb-s-85k-iops), but that same drive set in a box connected with SATA 2 (3Gbits) would only yield around 280MiBytes per second thus losing almost 100MiBytes per second throughput and a ton of IOps too. So why the hell are “enterprise” vendors still only connecting SSD’s at 3GBits? Well, my conspiracy states that they have no interest in you moving to SSD because they’ll lose so much money, the argument that they use SATA 2 doesn’t wash, SATA 3 has been out for some time now and all the commodity stuff you buy uses it now. Consider the cost, not in terms of price per GB but price per IOps, SSD absolutely thrash Hard Drives on that, it was true that the opposite was also true that Hard Drives thrashed SSD’s on price per GB, but is that true now, I’m not so sure – a 300GByte 2.5” 15Krpm SAS drive costs £329.76 ex VAT (http://www.scan.co.uk/products/300gb-seagate-st9300653ss-savvio-15k3-25-hdd-sas-6gb-s-15000rpm-64mb-cache-27ms) which equates to £1.09 per GB compared to a 480GB OCZ Agility 3 costing £422.10 ex VAT (http://www.scan.co.uk/products/480gb-ocz-agility-3-ssd-25-sata-6gb-s-sandforce-2281-read-525mb-s-write-410mb-s-30k-iops) which equates to £0.88 per GB. Ok, I compared an “enterprise” hard drive with a “commodity” SSD, ok, so things get a little more complicated here, most “enterprise” SSD’s are SLC and most commodity are MLC, SLC gives more performance and wear, I’ll talk about that another day. For now though, don’t get sucked in by vendor marketing, SATA 2 (3Gbit) just doesn’t cut it, SSD need 6Gbit to breath and even that SSD’s are pushing. Alas, SSD’s are connected using SATA so all the controllers I’ve seen thus far from HP and DELL only do SATA 2 – deliberate? Well, I’ll let you decide on that one.

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  • SQL SERVER – Performance Tuning Resolution

    - by pinaldave
    This blog post is written in response to T-SQL Tuesday hosted by MidnightDBAs. Taking resolutions is such an interesting subject. I think just like records, these are broken way more often. I find this is the funniest thing as we all take resolutions every year but not every year, we can manage to keep them. Well, does it mean we should not take resolutions? In fact I support resolutions. Every year, I take a resolution that I will strive reduce my body weight and I usually manage to keep eating healthy till the end of January. When February begins, I begin to loose focus from my goal and as March starts, the “As usual” eating habits begin. Looking at the positive side, what would happen if every year I do not eat healthy in January, I think that might cause terrible consequences to my health in the long run. So keeping resolutions is a good practise and following them to the extent one can is commendable. Let us come back to the world of SQL Server. What is my resolution for year 2011 for SQL Server? There are many, I am going to list three of very important resolutions that I have taken this new year over here. To understand SQL Server Performance Tuning at a deeper Level I think I am already half way through. I have been being very much busy during any given month doing hands-on performance tuning for at least 12 days on an average. That means, I am doing this activity for almost doing 2 weeks a month. I believe that I have a good understanding of the subject. Note that the word that I have used is “good,” and not “best.” There are often cases when I am stumped, and I have no clue of what to do next. Then, I usually go for my “trial and error” method - whichever method works, I make sure to keep a note on my blog. My goal is that I should never ever go for the trial and error method again to achieve the same solution. I should know the solution right away when I see the problem. I do understand that Performance Tuning can be a strange animal at times and one cannot guess the right step every time. However, aiming a high goal never hurts and I am going to learn more and more in this focused area. Going further from Basic BI understanding I do fairly decent with BI concepts. I know the nbasics of SSIS, SSRS, SSAS, PowerPivot and SharePoint (and few other things MDS, StreamInsight, etc). However, I still consider myself as a beginner. I do not have hands-on experience like many other BI Gurus around. I think I want to take my learning further in this direction. I do not want to be a BI expert as the first step but the goal is to move ahead from basic level towards an advanced level. I am going to start presenting in User Group Sessions and other places on this subject. When I have to prepare new subject for presentations, I think I force myself to learn more. I am committed to learn a bit more in this direction. Learning new features SQL Server 2011 Denali This is new thing from “Microsoft” for all the SQL Geeks. I am eagerly waiting for final product later this year and I am planning to learn it well. I think if I follow my above two goals, I think this goal will be automatically covered. I am eager and excited for this new offering from Microsoft. I guess, these are my resolutions; may be next year about the same time, I must revisit this post and see how much successful I am in following my goal. On a lighter note, I am particularly fan of following cartoon strip (Courtesy: Calvin and Hobbes). I think when we cannot resolve our resolutions, we tend to act like Calvin. Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: About Me, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • Visual Studio 2010 on Macbook Air

    - by Kyle B.
    Does anyone here run Visual Studio 2010 (or VS12 RC) on a Macbook Air? I have the current model with 4GB ram, 13" screen, and 256GB SSD drive. Before I go through the effort of configuring this, I'd like to know if anyone from the community has done this and: Was the performance acceptable? If it is, I plan to get a larger cinema display monitor as a second display and do all my coding on this machine ditching my desktop. Did you use Boot camp, Parallels, or VMWare? I feel to maximize performance that boot camp would be necessary to make the most utilization of the memory, but am not sure if this completely necessary. I'd prefer to use a VM, but wasn't sure if this was practical and would value your input before buying a license. Did you also run anything else on the Windows installation, such as SQL Server express, IISExpress, etc? Did performance lag after a certain point? Note: I would have asked this in superuser.com, but felt this applied more directly to the programming community.

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