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  • Unable to boot: Missing Operating system

    - by Vivek S Panicker
    i had installed Ubuntu 11.10 along with the another Ubuntu 11.10 which already installed in my netbook. Later I formatted the partition I newly installed. Next time when I boot it went to Grub Rescue menu. I boot my system again with Ubuntu USB stick, Then I installed Boot repair package in USB and restored MBR and GRUB menu in hard disk. Now when I am restarting, I am getting a message Missing operating system, press any key to continue. Can somebody help me on this? Below is the output for sudo fdisk -l omitting empty partition (7) Disk /dev/sda: 160.0 GB, 160041885696 bytes 255 heads, 63 sectors/track, 19457 cylinders, total 312581808 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00058a60 Device Boot Start End Blocks Id System /dev/sda1 * 2048 204072287 102035120 83 Linux /dev/sda2 204072958 312580095 54253569 5 Extended /dev/sda5 310507520 312580095 1036288 82 Linux swap / Solaris /dev/sda6 308432896 310503423 1035264 82 Linux swap / Solaris Partition table entries are not in disk order Disk /dev/sdb: 4006 MB, 4006608896 bytes 124 heads, 62 sectors/track, 1017 cylinders, total 7825408 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x0004d3df Device Boot Start End Blocks Id System /dev/sdb1 * 62 7818695 3909317 b W95 FAT32 Below is the output for sudo blkid /dev/loop0: TYPE="squashfs" /dev/loop1: LABEL="casper-rw" UUID="533defb1-f073-254a-b46f-7ca0ac1f4e0c" TYPE="ext2" /dev/sda1: LABEL="Ubuntu" UUID="6a141040-3ba8-457a-9de5-ad06e6057084" TYPE="ext4" /dev/sda5: UUID="3a7f62d6-9c65-4d12-a3b6-5d62b9710f7d" TYPE="swap" /dev/sda6: UUID="274da115-cec2-4418-a1af-88fe921e3670" TYPE="swap" /dev/sdb1: LABEL="PENDRIVE" UUID="EC22-6BE4" TYPE="vfat" File /boot/grub/grub.cfg # # DO NOT EDIT THIS FILE # # It is automatically generated by grub-mkconfig using templates # from /etc/grub.d and settings from /etc/default/grub # ### BEGIN /etc/grub.d/00_header ### if [ -s $prefix/grubenv ]; then set have_grubenv=true load_env fi set default="0" if [ "${prev_saved_entry}" ]; then set saved_entry="${prev_saved_entry}" save_env saved_entry set prev_saved_entry= save_env prev_saved_entry set boot_once=true fi function savedefault { if [ -z "${boot_once}" ]; then saved_entry="${chosen}" save_env saved_entry fi } function recordfail { set recordfail=1 if [ -n "${have_grubenv}" ]; then if [ -z "${boot_once}" ]; then save_env recordfail; fi; fi } function load_video { insmod vbe insmod vga insmod video_bochs insmod video_cirrus } insmod part_msdos insmod ext2 set root='(hd0,msdos1)' search --no-floppy --fs-uuid --set=root 6a141040-3ba8-457a-9de5-ad06e6057084 if loadfont /usr/share/grub/unicode.pf2 ; then set gfxmode=auto load_video insmod gfxterm insmod part_msdos insmod ext2 set root='(hd0,msdos1)' search --no-floppy --fs-uuid --set=root 6a141040-3ba8-457a-9de5-ad06e6057084 set locale_dir=($root)/boot/grub/locale set lang=en_US insmod gettext fi terminal_output gfxterm if [ "${recordfail}" = 1 ]; then set timeout=10 else set timeout=10 fi ### END /etc/grub.d/00_header ### ### BEGIN /etc/grub.d/05_debian_theme ### set menu_color_normal=white/black set menu_color_highlight=black/light-gray if background_color 44,0,30; then clear fi ### END /etc/grub.d/05_debian_theme ### ### BEGIN /etc/grub.d/10_linux ### if [ ${recordfail} != 1 ]; then if [ -e ${prefix}/gfxblacklist.txt ]; then if hwmatch ${prefix}/gfxblacklist.txt 3; then if [ ${match} = 0 ]; then set linux_gfx_mode=keep else set linux_gfx_mode=text fi else set linux_gfx_mode=text fi else set linux_gfx_mode=keep fi else set linux_gfx_mode=text fi export linux_gfx_mode if [ "$linux_gfx_mode" != "text" ]; then load_video; fi menuentry 'Ubuntu, with Linux 3.0.0-12-generic' --class ubuntu --class gnu-linux --class gnu --class os { recordfail set gfxpayload=$linux_gfx_mode insmod gzio insmod part_msdos insmod ext2 set root='(hd0,msdos1)' search --no-floppy --fs-uuid --set=root 6a141040-3ba8-457a-9de5-ad06e6057084 linux /boot/vmlinuz-3.0.0-12-generic root=UUID=6a141040-3ba8-457a-9de5-ad06e6057084 ro quiet splash vt.handoff=7 initrd /boot/initrd.img-3.0.0-12-generic } menuentry 'Ubuntu, with Linux 3.0.0-12-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os { recordfail insmod gzio insmod part_msdos insmod ext2 set root='(hd0,msdos1)' search --no-floppy --fs-uuid --set=root 6a141040-3ba8-457a-9de5-ad06e6057084 echo 'Loading Linux 3.0.0-12-generic ...' linux /boot/vmlinuz-3.0.0-12-generic root=UUID=6a141040-3ba8-457a-9de5-ad06e6057084 ro recovery nomodeset echo 'Loading initial ramdisk ...' initrd /boot/initrd.img-3.0.0-12-generic } ### END /etc/grub.d/10_linux ### ### BEGIN /etc/grub.d/20_linux_xen ### ### END /etc/grub.d/20_linux_xen ### ### BEGIN /etc/grub.d/20_memtest86+ ### menuentry "Memory test (memtest86+)" { insmod part_msdos insmod ext2 set root='(hd0,msdos1)' search --no-floppy --fs-uuid --set=root 6a141040-3ba8-457a-9de5-ad06e6057084 linux16 /boot/memtest86+.bin } menuentry "Memory test (memtest86+, serial console 115200)" { insmod part_msdos insmod ext2 set root='(hd0,msdos1)' search --no-floppy --fs-uuid --set=root 6a141040-3ba8-457a-9de5-ad06e6057084 linux16 /boot/memtest86+.bin console=ttyS0,115200n8 } ### END /etc/grub.d/20_memtest86+ ### ### BEGIN /etc/grub.d/30_os-prober ### ### END /etc/grub.d/30_os-prober ### ### BEGIN /etc/grub.d/40_custom ### # This file provides an easy way to add custom menu entries. Simply type the # menu entries you want to add after this comment. Be careful not to change # the 'exec tail' line above. ### END /etc/grub.d/40_custom ### ### BEGIN /etc/grub.d/41_custom ### if [ -f $prefix/custom.cfg ]; then source $prefix/custom.cfg; fi ### END /etc/grub.d/41_custom ###

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  • What's the best platform for blogging about coding ?

    - by timday
    I'm toying with starting an occasional blog for posting odd bits of coding related stuff (mainly C++, probably). Are there any platforms which can be recommended as providing exceptionally good support (e.g syntax highlighting) for posting snippets of code ? (Or any to avoid because posting mono-spaced font blocks of text is a pain). Outcome: I accepted Josh K's answer because what I actually ended up doing was realizing I was more interested in articles than a blog style, getting back into LaTeX (after almost 20 years away from it), using the "listings" package for code, and pushing the HTML/PDF results to my ISP's static-hosting pages. (HTML generated using tex4ht). Kudos to the answers mentioning Wordpress, Tumblr and Jekyll; I spent some time looking into all of them.

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  • Simple SST Unhooker

    This article includes description of simple unhooker that restores original SST hooked by unknown rootkits, which hide some services and processes.

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  • Automate Your Google Analytics Reporting with Apps Script

    Automate Your Google Analytics Reporting with Apps Script Do you rely on Google Analytics reporting to make sure you're making the most of your web traffic? Does your current process for exporting and analyzing your Analytics data feel clunky? Join Nick Mihailovski and Ikai Lan from the Analytics and Apps Script teams to learn how to integrate Google Analytics with Apps Script and save your sanity in the process. From: GoogleDevelopers Views: 0 2 ratings Time: 30:00 More in Science & Technology

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  • Google I/O 2012 - Deep Dive into the Next Version of the Google Drive API

    Google I/O 2012 - Deep Dive into the Next Version of the Google Drive API Ali Afshar, Ivan Lee This session discusses a number of best practices with the new Google Drive API. We'll cover how to properly sync files, how to manage sharing, and how to make your applications faster and more efficient than ever before. We'll go through an entire working application that exposes best practices. For all I/O 2012 sessions, go to developers.google.com From: GoogleDevelopers Views: 17 0 ratings Time: 45:50 More in Science & Technology

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  • Why is using C++ libraries is so complicated?

    - by Pius
    First of all, I want to note I love C++ and I'm one of those people who thinks it is easier to code in C++ than Java. Except for one tiny thing: libraries. In Java you can simply add some jar to the build path and you're done. In C++ you usually have to set multiple paths for the header files and the library itself. In some cases, you even have to use special build flags. I have mainly used Visual Studio, Code Blocks and no IDE at all. All 3 options do not differ much when talking about using external libraries. I wonder why was there made no simpler alternative for this? Like having a special .zip file that has everything you need in one place so the IDE can do all the work for you setting up the build flags. Is there any technical barrier for this?

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  • Should programming languages be strict or loose?

    - by Ralph
    In Python and JavaScript, semi-colons are optional. In PHP, quotes around array-keys are optional ($_GET[key] vs $_GET['key']), although if you omit them it will first look for a constant by that name. It also allows 2 different styles for blocks (colon, or brace delimited). I'm creating a programming language now, and I'm trying to decide how strict I should make it. There are a lot of cases where extra characters aren't really necessary and can be unambiguously interpreted due to priorities, but I'm wondering if I should still enforce them or not to encourage good programming habits. What do you think?

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  • Google I/O 2012 - How to Build Apps that Love Each Other with Web Intents

    Google I/O 2012 - How to Build Apps that Love Each Other with Web Intents Paul Kinlan, James Hawkins Web Intents allows you to build applications that integrate with one another with an ease that has never been seen on the web before. In this session we will show you how to connect applications using Web Intents and how to best integrate with the many actions available in Web Intents such as editing, saving and sharing. For all I/O 2012 sessions, go to developers.google.com From: GoogleDevelopers Views: 1394 15 ratings Time: 57:48 More in Science & Technology

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  • Senior Developers vs. Junior

    - by huwyss
    I like the following quote which I found on codinghorror:[As Steve points out this is one key difference between junior and senior developers:] In the old days, seeing too much code at once quite frankly exceeded my complexity threshold, and when I had to work with it I'd typically try to rewrite it or at least comment it heavily. Today, however, I just slog through it without complaining (much). When I have a specific goal in mind and a complicated piece of code to write, I spend my time making it happen rather than telling myself stories about it [in comments].

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  • Can't see my partitions after grub recovery

    - by dimbo
    I stupidly inserted the windows CD into my dual boot Ubuntu 11.10 / windows xp system. I just wanted to see if I could install windows on my external usb HD, but didn't actually go ahead with the install. It seems like the windows CD messed up my MBR and I had to use boot-repair and the ubuntu 11.10 live CD to gain access to ubuntu again. It seems to boot up a little differently (slower) but works. However, I now cant see any of my partitions in nautilus (there are 3). When I open gparted, it just shows my whole hard drive as unallocated (I know it has a windows partition that works and my ubuntu partition that I am using now). If I insert a usb pen, it is also not visible in nautilus but in gparted shows up as a FAT32 partition (which is correct although I cannot access it). sudo fdisk -l gives the following : demian@dimbo-TP:~$ sudo fdisk -l [sudo] password for demian: omitting empty partition (5) Disk /dev/sda: 320.1 GB, 320072933376 bytes 240 heads, 63 sectors/track, 41345 cylinders, total 625142448 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x877b877b Device Boot Start End Blocks Id System /dev/sda1 * 63 63842309 31921123+ 7 HPFS/NTFS/exFAT /dev/sda2 63844350 133484084 34819867+ 5 Extended /dev/sda3 127636488 133484084 2923798+ 82 Linux swap / Solaris /dev/sda4 133484085 625137344 245826630 83 Linux /dev/sda5 63844352 123445247 29800448 83 Linux /dev/sda6 123447296 127635455 2094080 82 Linux swap / Solaris Disk /dev/sdb: 8100 MB, 8100249600 bytes 12 heads, 40 sectors/track, 32960 cylinders, total 15820800 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0xc3072e18 Device Boot Start End Blocks Id System /dev/sdb1 * 5992 15820799 7907404 c W95 FAT32 (LBA) Here is my grub.conf file. Like I said before, I had to use the 'boot-repair' utility with the live cd to get grub working again. I think that this utility maybe created a new grub for me because the startup is definitely not the same. The screen goes blank for a while, and then the ubuntu loading dots come up for a brief moment (instead of during the whole startup process) before the dektop is displayed. Anyway : # DO NOT EDIT THIS FILE # # It is automatically generated by grub-mkconfig using templates # from /etc/grub.d and settings from /etc/default/grub # ### BEGIN /etc/grub.d/00_header ### if [ -s $prefix/grubenv ]; then set have_grubenv=true load_env fi set default="0" if [ "${prev_saved_entry}" ]; then set saved_entry="${prev_saved_entry}" save_env saved_entry set prev_saved_entry= save_env prev_saved_entry set boot_once=true fi function savedefault { if [ -z "${boot_once}" ]; then saved_entry="${chosen}" save_env saved_entry fi } function recordfail { set recordfail=1 if [ -n "${have_grubenv}" ]; then if [ -z "${boot_once}" ]; then save_env recordfail; fi; fi } function load_video { insmod vbe insmod vga insmod video_bochs insmod video_cirrus } insmod part_msdos insmod ext2 set root='(hd0,msdos6)' search --no-floppy --fs-uuid --set=root 5349ff67-b7b7-489f-a881-ae49c1dcd84a if loadfont /usr/share/grub/unicode.pf2 ; then set gfxmode=auto load_video insmod gfxterm insmod part_msdos insmod ext2 set root='(hd0,msdos6)' search --no-floppy --fs-uuid --set=root 5349ff67-b7b7-489f-a881-ae49c1dcd84a set locale_dir=($root)/boot/grub/locale set lang=en_US insmod gettext fi terminal_output gfxterm if [ "${recordfail}" = 1 ]; then set timeout=10 else set timeout=10 fi ### END /etc/grub.d/00_header ### ### BEGIN /etc/grub.d/05_debian_theme ### set menu_color_normal=white/black set menu_color_highlight=black/light-gray if background_color 44,0,30; then clear fi ### END /etc/grub.d/05_debian_theme ### ### BEGIN /etc/grub.d/10_linux ### if [ ${recordfail} != 1 ]; then if [ -e ${prefix}/gfxblacklist.txt ]; then if hwmatch ${prefix}/gfxblacklist.txt 3; then if [ ${match} = 0 ]; then set linux_gfx_mode=keep else set linux_gfx_mode=text fi else set linux_gfx_mode=text fi else set linux_gfx_mode=keep fi else set linux_gfx_mode=text fi export linux_gfx_mode if [ "$linux_gfx_mode" != "text" ]; then load_video; fi menuentry 'Ubuntu, with Linux 3.0.0-12-generic' --class ubuntu --class gnu-linux --class gnu --class os { recordfail set gfxpayload=$linux_gfx_mode insmod gzio insmod part_msdos insmod ext2 set root='(hd0,msdos6)' search --no-floppy --fs-uuid --set=root 5349ff67-b7b7-489f-a881-ae49c1dcd84a linux /boot/vmlinuz-3.0.0-12-generic root=UUID=5349ff67-b7b7-489f-a881-ae49c1dcd84a ro quiet splash vt.handoff=7 initrd /boot/initrd.img-3.0.0-12-generic } menuentry 'Ubuntu, with Linux 3.0.0-12-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os { recordfail insmod gzio insmod part_msdos insmod ext2 set root='(hd0,msdos6)' search --no-floppy --fs-uuid --set=root 5349ff67-b7b7-489f-a881-ae49c1dcd84a echo 'Loading Linux 3.0.0-12-generic ...' linux /boot/vmlinuz-3.0.0-12-generic root=UUID=5349ff67-b7b7-489f-a881-ae49c1dcd84a ro recovery nomodeset echo 'Loading initial ramdisk ...' initrd /boot/initrd.img-3.0.0-12-generic } ### END /etc/grub.d/10_linux ### ### BEGIN /etc/grub.d/20_linux_xen ### ### END /etc/grub.d/20_linux_xen ### ### BEGIN /etc/grub.d/20_memtest86+ ### menuentry "Memory test (memtest86+)" { insmod part_msdos insmod ext2 set root='(hd0,msdos6)' search --no-floppy --fs-uuid --set=root 5349ff67-b7b7-489f-a881-ae49c1dcd84a linux16 /boot/memtest86+.bin } menuentry "Memory test (memtest86+, serial console 115200)" { insmod part_msdos insmod ext2 set root='(hd0,msdos6)' search --no-floppy --fs-uuid --set=root 5349ff67-b7b7-489f-a881-ae49c1dcd84a linux16 /boot/memtest86+.bin console=ttyS0,115200n8 } ### END /etc/grub.d/20_memtest86+ ### ### BEGIN /etc/grub.d/30_os-prober ### menuentry "Microsoft Windows XP Professional (on /dev/sda1)" --class windows --class os { insmod part_msdos insmod ntfs set root='(hd0,msdos1)' search --no-floppy --fs-uuid --set=root 72A89361A89322A1 drivemap -s (hd0) ${root} chainloader +1 } ### END /etc/grub.d/30_os-prober ### ### BEGIN /etc/grub.d/40_custom ### # This file provides an easy way to add custom menu entries. Simply type the # menu entries you want to add after this comment. Be careful not to change # the 'exec tail' line above. ### END /etc/grub.d/40_custom ### ### BEGIN /etc/grub.d/41_custom ### if [ -f $prefix/custom.cfg ]; then source $prefix/custom.cfg; fi ### END /etc/grub.d/41_custom ### How can I get things back to normal. Thanks, Demian.

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  • Dual Boot Ubuntu and Windows 7: BOOTMGR is missing when I tried to boot in Windows

    - by Simon Polak
    So, I don't know what exactly how I managed to delete the MBR record on windows partition. But let me explain what I did next, I ran the ubuntu boot repair tool and now Windows is not even listed in my grub loader. So I went and booted with windows cd and choose repair. Then I ran ubuntu boot repair again via live cd. Here is the log http://paste.ubuntu.com/1426181/. Still no luck. Looks like osprobe can't detect windows on my /dev/sda2 partition. Any clues ? Here is how my partitions look like: Disk /dev/sda: 500.1 GB, 500107862016 bytes 255 heads, 63 sectors/track, 60801 cylinders, total 976773168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x525400d1 Device Boot Start End Blocks Id System /dev/sda1 * 2048 206847 102400 7 HPFS/NTFS/exFAT /dev/sda2 206848 509620669 254706911 7 HPFS/NTFS/exFAT /dev/sda3 509622270 976773119 233575425 5 Extended /dev/sda5 509622272 957757439 224067584 83 Linux /dev/sda6 957759488 976773119 9506816 82 Linux swap / Solaris

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  • Basic Defensive Database Programming Techniques

    We can all recognise good-quality database code: It doesn't break with every change in the server's configuration, or on upgrade. It isn't affected by concurrent usage, or high workload. In an extract from his forthcoming book, Alex explains just how to go about producing resilient TSQL code that works, and carries on working.

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  • Updating an Entity through a Service

    - by GeorgeK
    I'm separating my software into three main layers (maybe tiers would be a better term): Presentation ('Views') Business logic ('Services' and 'Repositories') Data access ('Entities' (e.g. ActiveRecords)) What do I have now? In Presentation, I use read-only access to Entities, returned from Repositories or Services, to display data. $banks = $banksRegistryService->getBanksRepository()->getBanksByCity( $city ); $banksViewModel = new PaginatedList( $banks ); // some way to display banks; // example, not real code I find this approach quite efficient in terms of performance and code maintanability and still safe as long as all write operations (create, update, delete) are preformed through a Service: namespace Service\BankRegistry; use Service\AbstractDatabaseService; use Service\IBankRegistryService; use Model\BankRegistry\Bank; class Service extends AbstractDatabaseService implements IBankRegistryService { /** * Registers a new Bank * * @param string $name Bank's name * @param string $bik Bank's Identification Code * @param string $correspondent_account Bank's correspondent account * * @return Bank */ public function registerBank( $name, $bik, $correspondent_account ) { $bank = new Bank(); $bank -> setName( $name ) -> setBik( $bik ) -> setCorrespondentAccount( $correspondent_account ); if( null === $this->getBanksRepository()->getDefaultBank() ) $this->setDefaultBank( $bank ); $this->getEntityManager()->persist( $bank ); return $bank; } /** * Makes the $bank system's default bank * * @param Bank $bank * @return IBankRegistryService */ public function setDefaultBank( Bank $bank ) { $default_bank = $this->getBanksRepository()->getDefaultBank(); if( null !== $default_bank ) $default_bank->setDefault( false ); $bank->setDefault( true ); return $this; } } Where am I stuck? I'm struggling about how to update certain fields in Bank Entity. Bad solution #1: Making a series of setters in Service for each setter in Bank; - seems to be quite reduntant, increases Service interface complexity and proportionally decreases it's simplicity - something to avoid if you care about code maitainability. I try to follow KISS and DRY principles. Bad solution #2: Modifying Bank directly through it's native setters; - really bad. If you'll ever need to move modification into the Service, it will be pain. Business logic should remain in Business logic layer. Plus, there are plans on logging all of the actions and maybe even involve user permissions (perhaps, through decorators) in future, so all modifications should be made only through the Service. Possible good solution: Creating an updateBank( Bank $bank, $array_of_fields_to_update) method; - makes the interface as simple as possible, but there is a problem: one should not try to manually set isDefault flag on a Bank, this operation should be performed through setDefaultBank method. It gets even worse when you have relations that you don't want to be directly modified. Of course, you can just limit the fields that can be modified by this method, but how do you tell method's user what they can and cannot modify? Exceptions?

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  • Google Top Geek E07

    Google Top Geek E07 In Spanish! Noticias: 1. Gráfico de conocimiento ahora en español y varios idiomas más. Totalmente localizado. 2. Nueva versión de Snapseed para iOS y Android. Gmail para Android y la versión 2.0 para iOS. Nuevo estilo para YouTube. 3. 500Millones de usuarios en Google+ y una nueva característica: comunidades. Las búsquedas de la semana y lo más visto en YouTube. Recomendamos Picket, una app para Android que funciona en México y te da la cartelera en cines. Noticias para desarrolladores: 1. Mejores mapas para apps de Android, nuevo API. 2. Una imagen dice más que mil palabras: Place Photos y Radar Search Ligas y más información en el blog: programa-con-google.blogspot.com From: GoogleDevelopers Views: 80 11 ratings Time: 18:09 More in Science & Technology

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  • Throwing exception from a property when my object state is invalid

    - by Rumi P.
    Microsoft guidelines say: "Avoid throwing exceptions from property getters", and I normally follow that. But my application uses Linq2SQL, and there is the case where my object can be in invalid state because somebody or something wrote nonsense into the database. Consider this toy example: [Table(Name="Rectangle")] public class Rectangle { [Column(Name="ID", IsPrimaryKey = true, IsDbGenerated = true)] public int ID {get; set;} [Column(Name="firstSide")] public double firstSide {get; set;} [Column(Name="secondSide")] public double secondSide {get; set;} public double sideRatio { get { return firstSide/secondSide; } } } Here, I could write code which ensures that my application never writes a Rectangle with a zero-length side into the database. But no matter how bulletproof I make my own code, somebody could open the database with a different application and create an invalid Rectangle, especially one with a 0 for secondSide. (For this example, please forget that it is possible to design the database in a way such that writing a side length of zero into the rectangle table is impossible; my domain model is very complex and there are constraints on model state which cannot be expressed in a relational database). So, the solution I am gravitating to is to change the getter to: get { if(firstSide > 0 && secondSide > 0) return firstSide/secondSide; else throw new System.InvalidOperationException("All rectangle sides should have a positive length"); } The reasoning behind not throwing exceptions from properties is that programmers should be able to use them without having to make precautions about catching and handling them them. But in this case, I think that it is OK to continue to use this property without such precautions: if the exception is thrown because my application wrote a non-zero rectangle side into the database, then this is a serious bug. It cannot and shouldn't be handled in the application, but there should be code which prevents it. It is good that the exception is visibly thrown, because that way the bug is caught. if the exception is thrown because a different application changed the data in the database, then handling it is outside of the scope of my application. So I can't do anything about it if I catch it. Is this a good enough reasoning to get over the "avoid" part of the guideline and throw the exception? Or should I turn it into a method after all? Note that in the real code, the properties which can have an invalid state feel less like the result of a calculation, so they are "natural" properties, not methods.

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