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• Grub 'Read Error' - Only Loads with LiveCD

  - by Ryan Sharp

  Problem After installing Ubuntu to complete my Windows 7/Ubuntu 12.04 dual-boot setup, Grub just wouldn't load at all unless I boot from the LiveCD. Afterwards, everything works completely normal. However, this workaround isn't a solution and I'd like to be able to boot without the aid of a disc. Fdisk -l Using the fdisk -l command, I am given the following: Disk /dev/sda: 64.0 GB, 64023257088 bytes 255 heads, 63 sectors/track, 7783 cylinders, total 125045424 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: 0x324971d1 Device Boot Start End Blocks Id System /dev/sda1 2048 206847 102400 7 HPFS/NTFS/exFAT /dev/sda2 208896 48957439 24374272 7 HPFS/NTFS/exFAT /dev/sda3 * 48959486 124067839 37554177 5 Extended /dev/sda5 48959488 124067839 37554176 83 Linux Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 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: 0xc0ee6a69 Device Boot Start End Blocks Id System /dev/sdb1 1024208894 1953523711 464657409 5 Extended /dev/sdb3 * 2048 1024206847 512102400 7 HPFS/NTFS/exFAT /dev/sdb5 1024208896 1937897471 456844288 83 Linux /dev/sdb6 1937899520 1953523711 7812096 82 Linux swap / Solaris Partition table entries are not in disk order Disk /dev/sdc: 320.1 GB, 320072933376 bytes 255 heads, 63 sectors/track, 38913 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: 0x292eee23 Device Boot Start End Blocks Id System /dev/sdc1 2048 625141759 312569856 7 HPFS/NTFS/exFAT Bootinfoscript I've used the BootInfoScript, and received the following output: Boot Info Script 0.61 [1 April 2012] ============================= Boot Info Summary: =============================== => Grub2 (v1.99) is installed in the MBR of /dev/sda and looks at sector 1 of the same hard drive for core.img. core.img is at this location and looks for (,msdos5)/boot/grub on this drive. => Grub2 (v1.99) is installed in the MBR of /dev/sdb and looks at sector 1 of the same hard drive for core.img. core.img is at this location and looks for (,msdos5)/boot/grub on this drive. => Windows is installed in the MBR of /dev/sdc. sda1: __________________________________________________________________________ File system: ntfs Boot sector type: Windows Vista/7: NTFS Boot sector info: No errors found in the Boot Parameter Block. Operating System: Boot files: /bootmgr /Boot/BCD sda2: __________________________________________________________________________ File system: ntfs Boot sector type: Windows Vista/7: NTFS Boot sector info: No errors found in the Boot Parameter Block. Operating System: Windows 7 Boot files: /bootmgr /Boot/BCD /Windows/System32/winload.exe sda3: __________________________________________________________________________ File system: Extended Partition Boot sector type: Unknown Boot sector info: sda5: __________________________________________________________________________ File system: ext4 Boot sector type: - Boot sector info: Operating System: Ubuntu 12.04.1 LTS Boot files: /boot/grub/grub.cfg /etc/fstab /boot/grub/core.img sdb1: __________________________________________________________________________ File system: Extended Partition Boot sector type: - Boot sector info: sdb5: __________________________________________________________________________ File system: ext4 Boot sector type: - Boot sector info: Operating System: Boot files: sdb6: __________________________________________________________________________ File system: swap Boot sector type: - Boot sector info: sdb3: __________________________________________________________________________ File system: ntfs Boot sector type: Windows Vista/7: NTFS Boot sector info: According to the info in the boot sector, sdb3 starts at sector 200744960. But according to the info from fdisk, sdb3 starts at sector 2048. According to the info in the boot sector, sdb3 has 823461887 sectors, but according to the info from fdisk, it has 1024204799 sectors. Operating System: Boot files: sdc1: __________________________________________________________________________ File system: ntfs Boot sector type: Windows Vista/7: NTFS Boot sector info: No errors found in the Boot Parameter Block. Operating System: Boot files: ============================ Drive/Partition Info: ============================= Drive: sda _____________________________________________________________________ Disk /dev/sda: 64.0 GB, 64023257088 bytes 255 heads, 63 sectors/track, 7783 cylinders, total 125045424 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes Partition Boot Start Sector End Sector # of Sectors Id System /dev/sda1 2,048 206,847 204,800 7 NTFS / exFAT / HPFS /dev/sda2 208,896 48,957,439 48,748,544 7 NTFS / exFAT / HPFS /dev/sda3 * 48,959,486 124,067,839 75,108,354 5 Extended /dev/sda5 48,959,488 124,067,839 75,108,352 83 Linux Drive: sdb _____________________________________________________________________ Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes Partition Boot Start Sector End Sector # of Sectors Id System /dev/sdb1 1,024,208,894 1,953,523,711 929,314,818 5 Extended /dev/sdb5 1,024,208,896 1,937,897,471 913,688,576 83 Linux /dev/sdb6 1,937,899,520 1,953,523,711 15,624,192 82 Linux swap / Solaris /dev/sdb3 * 2,048 1,024,206,847 1,024,204,800 7 NTFS / exFAT / HPFS Drive: sdc _____________________________________________________________________ Disk /dev/sdc: 320.1 GB, 320072933376 bytes 255 heads, 63 sectors/track, 38913 cylinders, total 625142448 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes Partition Boot Start Sector End Sector # of Sectors Id System /dev/sdc1 2,048 625,141,759 625,139,712 7 NTFS / exFAT / HPFS "blkid" output: ________________________________________________________________ Device UUID TYPE LABEL /dev/sda1 A48056DF8056B80E ntfs System Reserved /dev/sda2 A8C6D6A4C6D671D4 ntfs Windows /dev/sda5 fd71c537-3715-44e1-b1fe-07537e22b3dd ext4 /dev/sdb3 6373D03D0A3747A8 ntfs Steam /dev/sdb5 6f5a6eb3-a932-45aa-893e-045b57708270 ext4 /dev/sdb6 469848c8-867a-41b7-b0e1-b813a43c64af swap /dev/sdc1 725D7B961CF34B1B ntfs backup ================================ Mount points: ================================= Device Mount_Point Type Options /dev/sda5 / ext4 (rw,noatime,nodiratime,discard,errors=remount-ro) /dev/sdb5 /home ext4 (rw) =========================== sda5/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 "${boot_once}" ]; then save_env recordfail; fi; fi } function load_video { insmod vbe insmod vga insmod video_bochs insmod video_cirrus } insmod part_msdos insmod ext2 set root='(hd0,msdos5)' search --no-floppy --fs-uuid --set=root fd71c537-3715-44e1-b1fe-07537e22b3dd if loadfont /usr/share/grub/unicode.pf2 ; then set gfxmode=auto load_video insmod gfxterm insmod part_msdos insmod ext2 set root='(hd0,msdos5)' search --no-floppy --fs-uuid --set=root fd71c537-3715-44e1-b1fe-07537e22b3dd set locale_dir=($root)/boot/grub/locale set lang=en_GB insmod gettext fi terminal_output gfxterm if [ "${recordfail}" = 1 ]; then set timeout=-1 else set timeout=10 fi ### END /etc/grub.d/00_header ### ### BEGIN /etc/grub.d/05_debian_theme ### set menu_color_normal=white/black set menu_color_highlight=black/light-gray if background_color 44,0,30; then clear fi ### END /etc/grub.d/05_debian_theme ### ### BEGIN /etc/grub.d/10_linux ### function gfxmode { set gfxpayload="${1}" if [ "${1}" = "keep" ]; then set vt_handoff=vt.handoff=7 else set vt_handoff= fi } if [ "${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 3.2.0-29-generic' --class ubuntu --class gnu-linux --class gnu --class os { recordfail gfxmode $linux_gfx_mode insmod gzio insmod part_msdos insmod ext2 set root='(hd0,msdos5)' search --no-floppy --fs-uuid --set=root fd71c537-3715-44e1-b1fe-07537e22b3dd linux /boot/vmlinuz-3.2.0-29-generic root=UUID=fd71c537-3715-44e1-b1fe-07537e22b3dd ro quiet splash $vt_handoff initrd /boot/initrd.img-3.2.0-29-generic } menuentry 'Ubuntu, with Linux 3.2.0-29-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os { recordfail insmod gzio insmod part_msdos insmod ext2 set root='(hd0,msdos5)' search --no-floppy --fs-uuid --set=root fd71c537-3715-44e1-b1fe-07537e22b3dd echo 'Loading Linux 3.2.0-29-generic ...' linux /boot/vmlinuz-3.2.0-29-generic root=UUID=fd71c537-3715-44e1-b1fe-07537e22b3dd ro recovery nomodeset echo 'Loading initial ramdisk ...' initrd /boot/initrd.img-3.2.0-29-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,msdos5)' search --no-floppy --fs-uuid --set=root fd71c537-3715-44e1-b1fe-07537e22b3dd linux16 /boot/memtest86+.bin } menuentry "Memory test (memtest86+, serial console 115200)" { insmod part_msdos insmod ext2 set root='(hd0,msdos5)' search --no-floppy --fs-uuid --set=root fd71c537-3715-44e1-b1fe-07537e22b3dd linux16 /boot/memtest86+.bin console=ttyS0,115200n8 } ### END /etc/grub.d/20_memtest86+ ### ### BEGIN /etc/grub.d/30_os-prober ### menuentry "Windows 7 (loader) (on /dev/sda1)" --class windows --class os { insmod part_msdos insmod ntfs set root='(hd0,msdos1)' search --no-floppy --fs-uuid --set=root A48056DF8056B80E chainloader +1 } menuentry "Windows 7 (loader) (on /dev/sda2)" --class windows --class os { insmod part_msdos insmod ntfs set root='(hd0,msdos2)' search --no-floppy --fs-uuid --set=root A8C6D6A4C6D671D4 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 ### -------------------------------------------------------------------------------- =============================== sda5/etc/fstab: ================================ -------------------------------------------------------------------------------- # /etc/fstab: static file system information. # # Use 'blkid' to print the universally unique identifier for a # device; this may be used with UUID= as a more robust way to name devices # that works even if disks are added and removed. See fstab(5). # # <file system> <mount point> <type> <options> <dump> <pass> proc /proc proc nodev,noexec,nosuid 0 0 # / was on /dev/sda5 during installation UUID=fd71c537-3715-44e1-b1fe-07537e22b3dd / ext4 noatime,nodiratime,discard,errors=remount-ro 0 1 # /home was on /dev/sdb5 during installation UUID=6f5a6eb3-a932-45aa-893e-045b57708270 /home ext4 defaults 0 2 # swap was on /dev/sdb6 during installation UUID=469848c8-867a-41b7-b0e1-b813a43c64af none swap sw 0 0 tmpfs /tmp tmpfs defaults,noatime,mode=1777 0 0 -------------------------------------------------------------------------------- =================== sda5: Location of files loaded by Grub: ==================== GiB - GB File Fragment(s) = boot/grub/core.img 1 = boot/grub/grub.cfg 1 = boot/initrd.img-3.2.0-29-generic 2 = boot/vmlinuz-3.2.0-29-generic 1 = initrd.img 2 = vmlinuz 1 ======================== Unknown MBRs/Boot Sectors/etc: ======================== Unknown BootLoader on sda3 00000000 63 6f 70 69 61 20 65 20 63 6f 6c 61 41 63 65 64 |copia e colaAced| 00000010 65 72 20 61 20 74 6f 64 6f 20 6f 20 74 65 78 74 |er a todo o text| 00000020 6f 20 66 61 6c 61 64 6f 20 75 74 69 6c 69 7a 61 |o falado utiliza| 00000030 6e 64 6f 20 61 20 63 6f 6e 76 65 72 73 c3 a3 6f |ndo a convers..o| 00000040 20 64 65 20 74 65 78 74 6f 20 70 61 72 61 20 76 | de texto para v| 00000050 6f 7a 4d 61 6e 69 70 75 6c 61 72 20 61 73 20 64 |ozManipular as d| 00000060 65 66 69 6e 69 c3 a7 c3 b5 65 73 20 71 75 65 20 |efini....es que | 00000070 63 6f 6e 74 72 6f 6c 61 6d 20 6f 20 61 63 65 73 |controlam o aces| 00000080 73 6f 20 64 65 20 57 65 62 73 69 74 65 73 20 61 |so de Websites a| 00000090 20 63 6f 6f 6b 69 65 73 2c 20 4a 61 76 61 53 63 | cookies, JavaSc| 000000a0 72 69 70 74 20 65 20 70 6c 75 67 2d 69 6e 73 4d |ript e plug-insM| 000000b0 61 6e 69 70 75 6c 61 72 20 61 73 20 64 65 66 69 |anipular as defi| 000000c0 6e 69 c3 a7 c3 b5 65 73 20 72 65 6c 61 63 69 6f |ni....es relacio| 000000d0 6e 61 64 61 73 20 63 6f 6d 20 70 72 69 76 61 63 |nadas com privac| 000000e0 69 64 61 64 65 41 63 65 64 65 72 20 61 6f 73 20 |idadeAceder aos | 000000f0 73 65 75 73 20 70 65 72 69 66 c3 a9 72 69 63 6f |seus perif..rico| 00000100 73 20 55 53 42 55 74 69 6c 69 7a 61 72 20 6f 20 |s USBUtilizar o | 00000110 73 65 75 20 6d 69 63 72 6f 66 6f 6e 65 55 74 69 |seu microfoneUti| 00000120 6c 69 7a 61 72 20 61 20 73 75 61 20 63 c3 a2 6d |lizar a sua c..m| 00000130 61 72 61 55 74 69 6c 69 7a 61 72 20 6f 20 73 65 |araUtilizar o se| 00000140 75 20 6d 69 63 72 6f 66 6f 6e 65 20 65 20 61 20 |u microfone e a | 00000150 63 c3 a2 6d 61 72 61 4e c3 a3 6f 20 66 6f 69 20 |c..maraN..o foi | 00000160 70 6f 73 73 c3 ad 76 65 6c 20 65 6e 63 6f 6e 74 |poss..vel encont| 00000170 72 61 72 20 6f 20 63 61 6d 69 6e 68 6f 20 61 62 |rar o caminho ab| 00000180 73 6f 6c 75 74 6f 20 70 61 72 61 20 6f 20 64 69 |soluto para o di| 00000190 72 65 63 74 c3 b3 72 69 6f 20 61 20 65 6d 70 61 |rect..rio a empa| 000001a0 63 6f 74 61 72 2e 4f 20 64 69 72 65 63 74 c3 b3 |cotar.O direct..| 000001b0 72 69 6f 20 64 65 20 65 6e 74 72 61 64 61 00 fe |rio de entrada..| 000001c0 ff ff 83 fe ff ff 02 00 00 00 00 10 7a 04 00 00 |............z...| 000001d0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 000001f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.| 00000200 =============================== StdErr Messages: =============================== xz: (stdin): Compressed data is corrupt xz: (stdin): Compressed data is corrupt awk: cmd. line:36: Math support is not compiled in awk: cmd. line:36: Math support is not compiled in awk: cmd. line:36: Math support is not compiled in awk: cmd. line:36: Math support is not compiled in awk: cmd. line:36: Math support is not compiled in awk: cmd. line:36: Math support is not compiled in Begging / Appreciation ;) If anything else is required to solve my problem, please ask. My only hopes are that I can solve this, and that doing so won't require re-installation of Grub due to how complicated the procedures are, or that I would be needed to reinstall the OS', as I have done so about six times already since friday due to several other issues I've encountered. Thank you, and good day. System Ubuntu 12.04 64-bit / Windows 7 SP1 64-bit 64GB SSD as boot/OS drive, 1TB HDD as /Home Swap and Steam drive.

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• Take,Skip and Reverse Operator in Linq

  - by Jalpesh P. Vadgama

  I have found three more new operators in Linq which is use full in day to day programming stuff. Take,Skip and Reverse. Here are explanation of operators how it works. Take Operator: Take operator will return first N number of element from entities. Skip Operator: Skip operator will skip N number of element from entities and then return remaining elements as a result. Reverse Operator: As name suggest it will reverse order of elements of entities. Here is the examples of operators where i have taken simple string array to demonstrate that. C#, using GeSHi 1.0.8.6 using System; using System.Collections.Generic; using System.Linq; using System.Text;     namespace ConsoleApplication1 {     class Program     {         static void Main(string[] args)         {             string[] a = { "a", "b", "c", "d" };                           Console.WriteLine("Take Example");             var TkResult = a.Take(2);             foreach (string s in TkResult)             {                 Console.WriteLine(s);             }               Console.WriteLine("Skip Example");             var SkResult = a.Skip(2);             foreach (string s in SkResult)             {                 Console.WriteLine(s);             }               Console.WriteLine("Reverse Example");             var RvResult = a.Reverse();             foreach (string s in RvResult)             {                 Console.WriteLine(s);             }                       }     } } Parsed in 0.020 seconds at 44.65 KB/s Here is the output as expected. hope this will help you.. Technorati Tags: Linq,Linq-To-Sql,ASP.NET,C#.NET

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• VMWare vmfs vs NFS datastore with vmdk?

  - by CarpeNoctem

  I want to add a new harddisk to an existing VM and want the best performance possible. The new hard disk will exist on an NFS datastore. Currently I did the following: Created new vmdk on NFS datastore Created new lvm partition using fdisk Create new physical volume, volume group, and logical volume (2TB) Created ext3 partition on logical volume Is there a better way to do this? Should I be doing some vmware-ish file system instead?

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• Adaptec 5805 after reboot don't starting

  - by Rakedko ShotGuns

  After rebooting the system, the controller is not included. It only works if the computer is shut down and turn off. Late i update firmware "Adaptec RAID 5805 Firmware Build 18948" How to fix the problem? add Log Configuration summary Server name.....................raid_test Adaptec Storage Manager agent...7.31.00 (18856) Adaptec Storage Manager console.7.31.00 (18856) Number of controllers...........1 Operating system................Windows Configuration information for controller 1 ------------------------------------------------------- Type............................Controller Model...........................Adaptec 5805 Controller number...............1 Physical slot...................2 Installed memory size...........512 MB Serial number...................8C4510C6C9E Boot ROM........................5.2-0 (18948) Firmware........................5.2-0 (18948) Device driver...................5.2-0 (16119) Controller status...............Optimal Battery status..................Charging Battery temperature.............Normal Battery charge amount (%).......37 Estimated charge remaining......0 days, 16 hours, 12 minutes Background consistency check....Disabled Copy back.......................Disabled Controller temperature..........Normal (40C / 104F) Default logical drive task priorityHigh Performance mode................Dynamic Number of logical devices.......1 Number of hot-spare drives......0 Number of ready drives..........0 Number of drive(s) assigned to MaxCache cache0 Maximum drives allowed for MaxCache cache8 MaxCache Read Cache Pool Size...0 GB NCQ status......................Enabled Stay awake status...............Disabled Internal drive spinup limit.....0 External drive spinup limit.....0 Phy 0...........................No device attached Phy 1...........................No device attached Phy 2...........................No device attached Phy 3...........................1.50 Gb/s Phy 4...........................No device attached Phy 5...........................No device attached Phy 6...........................No device attached Phy 7...........................No device attached Statistics version..............2.0 SSD Cache size..................0 Pages on fetch list.............0 Fetch list candidates...........0 Candidate replacements..........0 69319...........................31293 Logical device..................0 Logical device name............. RAID level......................Simple volume Data space......................148,916 GB Date created....................09/19/2012 Interface type..................Serial ATA State...........................Optimal Read-cache mode.................Enabled Preferred MaxCache read cache settingEnabled Actual MaxCache read cache setting Disabled Write-cache mode................Enabled (write-back) Write-cache setting.............Enabled (write-back) Partitioned.....................Yes Protected by hot spare..........No Bootable........................Yes Bad stripes.....................No Power Status....................Disabled Power State.....................Active Reduce RPM timer................Never Power off timer.................Never Verify timer....................Never Segment 0.......................Present: controller 1, connector 0, device 0, S/N 9RX3KZMT Overall host IOs................99075 Overall MB......................4411203 DRAM cache hits.................71929 SSD cache hits..................0 Uncached IOs....................29239 Overall disk failures...........0 DRAM cache full hits............71929 DRAM cache fetch / flush wait...0 DRAM cache hybrid reads.........3476 DRAM cache flushes..............-- Read hits.......................0 Write hits......................0 Valid Pages.....................0 Updates on writes...............0 Invalidations by large writes...0 Invalidations by R/W balance....0 Invalidations by replacement....0 Invalidations by other..........0 Page Fetches....................0 0...............................0 73..............................10822 8...............................3 46138...........................4916 27184...........................15226 20875...........................323 16982...........................1771 1563............................5317 1948............................2969 Serial attached SCSI ----------------------- Type............................Disk drive Vendor..........................Unknown Model...........................ST3160815AS Serial Number...................9RX3KZMT Firmware level..................3.AAD Reported channel................0 Reported SCSI device ID.........0 Interface type..................Serial ATA Size............................149,05 GB Negotiated transfer speed.......1.50 Gb/s State...........................Optimal S.M.A.R.T. error................No Write-cache mode................Write back Hardware errors.................0 Medium errors...................0 Parity errors...................0 Link failures...................0 Aborted commands................0 S.M.A.R.T. warnings.............0 Solid-state disk (non-spinning).false MaxCache cache capable..........false MaxCache cache assigned.........false NCQ status......................Enabled Phy 0...........................1.50 Gb/s Power State.....................Full rpm Supported power states..........Full rpm, Powered off 0x01............................113 0x03............................98 0x04............................99 0x05............................100 0x07............................83 0x09............................75 0x0A............................100 0x0C............................99 0xBB............................100 0xBD............................100 0xBE............................61 0xC2............................39 0xC3............................69 0xC5............................100 0xC6............................100 0xC7............................200 0xC8............................100 0xCA............................100 Aborted commands................0 Link failures...................0 Medium errors...................0 Parity errors...................0 Hardware errors.................0 SMART errors....................0 End of the configuration information for controller 1 List item

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• Linux not picking up new partition correctly on emc pseudo device

  - by James

  Hi We have a database server running oracle rac. We were recently running out of space on the main LUN that it is attached to. I created a new 100GB LUN and concatenated this onto the existing LUN creating a new MetaLUN. After some messing I managed to get linux to recognise the new space. I then created a new partition in on the pseudo device, to use the new space. Previously when I have done this on other system the next step is to create an ASM disk on the new partition and add this disk to the oracle disk group. This however fails. I am aware of various issues with ASM and powerpath, but I don't think this is the issue here. As on while investigating the issue I discovered that one of the underlying logical device is not reflecting the size change. See below; Powermt displays all of the underlying logical units [root@XXXXX~]# powermt display dev=emcpowerd Pseudo name=emcpowerd CLARiiON ID=CKM00091500009 [VFRAC2] Logical device ID=6006016030312200787502866C65DE11 [LUN 30] state=alive; policy=CLAROpt; priority=0; queued-IOs=0 Owner: default=SP A, current=SP A Array failover mode: 1 ============================================================================== ---------------- Host --------------- - Stor - -- I/O Path - -- Stats --- ### HW Path I/O Paths Interf. Mode State Q-IOs Errors ============================================================================== 3 qla2xxx sde SP A0 active alive 0 0 3 qla2xxx sdj SP B0 active alive 0 0 4 qla2xxx sdo SP A1 active alive 0 0 4 qla2xxx sdt SP B1 active alive 0 0 Fdisk on the pseudo device shows correct space. [root@XXXXX ~]# fdisk -l /dev/emcpowerd Disk /dev/emcpowerd: 429.4 GB, 429496729600 bytes 255 heads, 63 sectors/track, 52216 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System /dev/emcpowerd1 1 39162 314568733+ 83 Linux /dev/emcpowerd2 39163 52216 104856255 83 Linux fdisk on one of the logical units is wrong [root@XXXXX~]# fdisk -l /dev/sde Disk /dev/sde: 322.1 GB, 322122547200 bytes 255 heads, 63 sectors/track, 39162 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System /dev/sde1 1 39162 314568733+ 83 Linux /dev/sde2 39163 52216 104856255 83 Linux fdisk on the rest of the units is fine [root@XXXXX ~]# fdisk -l /dev/sdj Disk /dev/sdj: 429.4 GB, 429496729600 bytes 255 heads, 63 sectors/track, 52216 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System /dev/sdj1 1 39162 314568733+ 83 Linux /dev/sdj2 39163 52216 104856255 83 Linux Also when I created the the partition linux did not create the any entries in the /dev directory for the second partition so I created these manually [root@XXXXX dev]# mknod sde2 b 8 66 [root@XXXXX dev]# ls -al sd[ejot]? brw-r----- 1 root disk 8, 65 Dec 29 14:20 sde1 brw-r--r-- 1 root disk 8, 66 Apr 8 20:31 sde2 brw-r----- 1 root disk 8, 145 Dec 29 14:19 sdj1 brw-r--r-- 1 root disk 8, 146 Apr 8 20:33 sdj2 brw-r----- 1 root disk 8, 225 Apr 6 23:12 sdo1 brw-r--r-- 1 root disk 8, 226 Apr 8 20:33 sdo2 brw-r----- 1 root disk 65, 49 Dec 29 14:19 sdt1 brw-r--r-- 1 root disk 65, 50 Apr 8 20:33 sdt2 This is a production server that we cannot easily reboot. Any ideas would be much appreciated. J

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• Resizing Partitions on Live RHEL/cPanel Server

  - by Timothy R. Butler

  I've resized many partitions over the years on Linux, Windows and Mac OS X -- but always using a GUI. However, the time has come where the preset partition sizes my data center placed on my server aren't the right sizes and I need to resize a production server's disks. I could fiddle with it and probably do OK, but given that it is a production server, I wanted to get some advice about the right way to do this. I do have KVM over IP access, so if it is best to take the server offline and boot off a rescue partition, I can do that. root [/var/lib/mysql]# df -h Filesystem Size Used Avail Use% Mounted on /dev/sda2 9.9G 2.1G 7.3G 23% / tmpfs 7.8G 0 7.8G 0% /dev/shm /dev/sda1 99M 77M 18M 82% /boot /dev/sda8 884G 463G 376G 56% /home /dev/sda3 9.9G 8.0G 1.5G 85% /usr /dev/sda5 9.9G 9.1G 308M 97% /var /usr/tmpDSK 2.0G 38M 1.8G 3% /tmp As you can see /var and /usr are quite close to being full and I've actually had to symlink some logs on /usr to directories in /home to balance things out. What I would like to do is to add 6-10 GB each to /usr and /var, presumably taking the space from /home. As I think about how the disk is arranged, the best thought I've come up with is to reduce /home by 16 GB, say, and move /var to the spot freed up, then allocating /var's space to /usr. However, that would put /var at the far end of the disk, which seems less than idea, given that MySQL has all of its data on that partition. I'd love to take the space out of the closer end of /usr, but I assume that would take a very arduous (and perhaps risky) process of moving all of the data in /usr around. I seem to recall having such a process fail for me on a computer in the past. The other option might be to merge / and /usr since / is underutilized, though I'm not sure if that's a good idea. Do you have any suggestions both on the best reallocation plan and the commands to use to accomplish it? UPDATE: I should add -- here's the partition table. There's one unused partition, which, if memory serves, was the original tmp location before I created a tmp image: Name Flags Part Type FS Type [Label] Size (MB) ------------------------------------------------------------------------------ Unusable 1.05* sda1 Boot Primary Linux ext2 106.96* sda2 Primary Linux ext3 10737.42* sda3 Primary Linux ext3 10737.42* sda5 NC Logical Linux ext3 10738.47* sda6 NC Logical Linux swap / Solaris 2148.54* sda7 NC Logical Linux ext3 1074.80* sda8 NC Logical Linux ext3 964098.53*

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• Oracle Fusion Supply Chain Management (SCM) Designs May Improve End User Productivity

  - by Applications User Experience

  By Applications User Experience on March 10, 2011 Michele Molnar, Senior Usability Engineer, Applications User Experience The Challenge: The SCM User Experience team, in close collaboration with product management and strategy, completely redesigned the user experience for Oracle Fusion applications. One of the goals of this redesign was to increase end user productivity by applying design patterns and guidelines and incorporating findings from extensive usability research. But a question remained: How do we know that the Oracle Fusion designs will actually increase end user productivity? The Test: To answer this question, the SCM Usability Engineers compared Oracle Fusion designs to their corresponding existing Oracle applications using the workflow time analysis method. The workflow time analysis method breaks tasks into a sequence of operators. By applying standard time estimates for all of the operators in the task, an estimate of the overall task time can be calculated. The workflow time analysis method has been recently adopted by the Applications User Experience group for use in predicting end user productivity. Using this method, a design can be tested and refined as needed to improve productivity even before the design is coded. For the study, we selected some of our recent designs for Oracle Fusion Product Information Management (PIM). The designs encompassed tasks performed by Product Managers to create, manage, and define products for their organization. (See Figure 1 for an example.) In applying this method, the SCM Usability Engineers collaborated with Product Management to compare the new Oracle Fusion Applications designs against Oracle’s existing applications. Together, we performed the following activities: Identified the five most frequently performed tasks Created detailed task scenarios that provided the context for each task Conducted task walkthroughs Analyzed and documented the steps and flow required to complete each task Applied standard time estimates to the operators in each task to estimate the overall task completion time Figure 1. The interactions on each Oracle Fusion Product Information Management screen were documented, as indicated by the red highlighting. The task scenario and script provided the context for each task.  The Results: The workflow time analysis method predicted that the Oracle Fusion Applications designs would result in productivity gains in each task, ranging from 8% to 62%, with an overall productivity gain of 43%. All other factors being equal, the new designs should enable these tasks to be completed in about half the time it takes with existing Oracle Applications. Further analysis revealed that these performance gains would be achieved by reducing the number of clicks and screens needed to complete the tasks. Conclusions: Using the workflow time analysis method, we can expect the Oracle Fusion Applications redesign to succeed in improving end user productivity. The workflow time analysis method appears to be an effective and efficient tool for testing, refining, and retesting designs to optimize productivity. The workflow time analysis method does not replace usability testing with end users, but it can be used as an early predictor of design productivity even before designs are coded. We are planning to conduct usability tests later in the development cycle to compare actual end user data with the workflow time analysis results. Such results can potentially be used to validate the productivity improvement predictions. Used together, the workflow time analysis method and usability testing will enable us to continue creating, evaluating, and delivering Oracle Fusion designs that exceed the expectations of our end users, both in the quality of the user experience and in productivity. (For more information about studying productivity, refer to the Measuring User Productivity blog.)

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• Adaptec 5805 not recognized after reboot

  - by Rakedko ShotGuns

  After rebooting the system, the controller is not recognized. It only works if the computer is shut down and turned off. I have recently updated the firmware to "Adaptec RAID 5805 Firmware Build 18948". How do I fix the problem? Configuration summary --------------------------- 1. Server name.....................raid_test Adaptec Storage Manager agent...7.31.00 (18856) Adaptec Storage Manager console.7.31.00 (18856) Number of controllers...........1 Operating system................Windows Configuration information for controller 1 ------------------------------------------------------- Type............................Controller Model...........................Adaptec 5805 Controller number...............1 Physical slot...................2 Installed memory size...........512 MB Serial number...................8C4510C6C9E Boot ROM........................5.2-0 (18948) Firmware........................5.2-0 (18948) Device driver...................5.2-0 (16119) Controller status...............Optimal Battery status..................Charging Battery temperature.............Normal Battery charge amount (%).......37 Estimated charge remaining......0 days, 16 hours, 12 minutes Background consistency check....Disabled Copy back.......................Disabled Controller temperature..........Normal (40C / 104F) Default logical drive task priority High Performance mode................Dynamic Number of logical devices.......1 Number of hot-spare drives......0 Number of ready drives..........0 Number of drive(s) assigned to MaxCache cache0 Maximum drives allowed for MaxCache cache8 MaxCache Read Cache Pool Size...0 GB NCQ status......................Enabled Stay awake status...............Disabled Internal drive spinup limit.....0 External drive spinup limit.....0 Phy 0...........................No device attached Phy 1...........................No device attached Phy 2...........................No device attached Phy 3...........................1.50 Gb/s Phy 4...........................No device attached Phy 5...........................No device attached Phy 6...........................No device attached Phy 7...........................No device attached Statistics version..............2.0 SSD Cache size..................0 Pages on fetch list.............0 Fetch list candidates...........0 Candidate replacements..........0 69319...........................31293 Logical device..................0 Logical device name............. RAID level......................Simple volume Data space......................148,916 GB Date created....................09/19/2012 Interface type..................Serial ATA State...........................Optimal Read-cache mode.................Enabled Preferred MaxCache read cache settingEnabled Actual MaxCache read cache setting Disabled Write-cache mode................Enabled (write-back) Write-cache setting.............Enabled (write-back) Partitioned.....................Yes Protected by hot spare..........No Bootable........................Yes Bad stripes.....................No Power Status....................Disabled Power State.....................Active Reduce RPM timer................Never Power off timer.................Never Verify timer....................Never Segment 0.......................Present: controller 1, connector 0, device 0, S/N 9RX3KZMT Overall host IOs................99075 Overall MB......................4411203 DRAM cache hits.................71929 SSD cache hits..................0 Uncached IOs....................29239 Overall disk failures...........0 DRAM cache full hits............71929 DRAM cache fetch / flush wait...0 DRAM cache hybrid reads.........3476 DRAM cache flushes..............-- Read hits.......................0 Write hits......................0 Valid Pages.....................0 Updates on writes...............0 Invalidations by large writes...0 Invalidations by R/W balance....0 Invalidations by replacement....0 Invalidations by other..........0 Page Fetches....................0 0...............................0 73..............................10822 8...............................3 46138...........................4916 27184...........................15226 20875...........................323 16982...........................1771 1563............................5317 1948............................2969 Serial attached SCSI ----------------------- Type............................Disk drive Vendor..........................Unknown Model...........................ST3160815AS Serial Number...................9RX3KZMT Firmware level..................3.AAD Reported channel................0 Reported SCSI device ID.........0 Interface type..................Serial ATA Size............................149,05 GB Negotiated transfer speed.......1.50 Gb/s State...........................Optimal S.M.A.R.T. error................No Write-cache mode................Write back Hardware errors.................0 Medium errors...................0 Parity errors...................0 Link failures...................0 Aborted commands................0 S.M.A.R.T. warnings.............0 Solid-state disk (non-spinning).false MaxCache cache capable..........false MaxCache cache assigned.........false NCQ status......................Enabled Phy 0...........................1.50 Gb/s Power State.....................Full rpm Supported power states..........Full rpm, Powered off 0x01............................113 0x03............................98 0x04............................99 0x05............................100 0x07............................83 0x09............................75 0x0A............................100 0x0C............................99 0xBB............................100 0xBD............................100 0xBE............................61 0xC2............................39 0xC3............................69 0xC5............................100 0xC6............................100 0xC7............................200 0xC8............................100 0xCA............................100 Aborted commands................0 Link failures...................0 Medium errors...................0 Parity errors...................0 Hardware errors.................0 SMART errors....................0 End of the configuration information for controller 1

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• Error 5 partition table invalid or corrupt

  - by Clodoaldo

  I'm trying to add a second SSD to a Centos 6 system. But I get the Error 5 partition table invalid or corrupt at boot. The system already has a single SSD (sdb) and a pair of HDDs (sd{a,c}) in a RAID 1 array from where it boots. It is as if the new SSD assumes one of the devices of the RAID array. Is it? How to avoid that or rearrange the setup? # cat fstab UUID=967b4035-782d-4c66-b22f-50244fe970ca / ext4 defaults 1 1 UUID=86fd06e9-cdc9-4166-ba9f-c237cfc43e02 /boot ext4 defaults 1 2 UUID=72552a7a-d8ae-4f0a-8917-b75a6239ce9f /ssd ext4 discard,relatime 1 2 UUID=8000e5e6-caa2-4765-94f8-9caeb2bda26e swap swap defaults 0 0 tmpfs /dev/shm tmpfs defaults 0 0 devpts /dev/pts devpts gid=5,mode=620 0 0 sysfs /sys sysfs defaults 0 0 proc /proc proc defaults 0 0 # ll /dev/disk/by-id/ total 0 lrwxrwxrwx. 1 root root 9 Jun 15 23:50 ata-OCZ-VERTEX3_OCZ-43DSRFTNCLE9ZJXX -> ../../sdb lrwxrwxrwx. 1 root root 10 Jun 15 23:50 ata-OCZ-VERTEX3_OCZ-43DSRFTNCLE9ZJXX-part1 -> ../../sdb1 lrwxrwxrwx. 1 root root 9 Jun 15 23:50 ata-ST3500413AS_5VMT49E3 -> ../../sdc lrwxrwxrwx. 1 root root 10 Jun 15 23:50 ata-ST3500413AS_5VMT49E3-part1 -> ../../sdc1 lrwxrwxrwx. 1 root root 10 Jun 15 23:50 ata-ST3500413AS_5VMT49E3-part2 -> ../../sdc2 lrwxrwxrwx. 1 root root 10 Jun 15 23:50 ata-ST3500413AS_5VMT49E3-part3 -> ../../sdc3 lrwxrwxrwx. 1 root root 9 Jun 15 23:50 ata-ST3500413AS_5VMTJNAJ -> ../../sda lrwxrwxrwx. 1 root root 10 Jun 15 23:50 ata-ST3500413AS_5VMTJNAJ-part1 -> ../../sda1 lrwxrwxrwx. 1 root root 10 Jun 15 23:50 ata-ST3500413AS_5VMTJNAJ-part2 -> ../../sda2 lrwxrwxrwx. 1 root root 10 Jun 15 23:50 ata-ST3500413AS_5VMTJNAJ-part3 -> ../../sda3 lrwxrwxrwx. 1 root root 9 Jun 15 23:50 md-name-localhost.localdomain:0 -> ../../md0 lrwxrwxrwx. 1 root root 9 Jun 15 23:50 md-name-localhost.localdomain:1 -> ../../md1 lrwxrwxrwx. 1 root root 9 Jun 15 23:50 md-name-localhost.localdomain:2 -> ../../md2 lrwxrwxrwx. 1 root root 9 Jun 15 23:50 md-uuid-a04d7241:8da6023e:f9004352:107a923a -> ../../md1 lrwxrwxrwx. 1 root root 9 Jun 15 23:50 md-uuid-a22c43b9:f1954990:d3ddda5e:f9aff3c9 -> ../../md0 lrwxrwxrwx. 1 root root 9 Jun 15 23:50 md-uuid-f403a2d0:447803b5:66edba73:569f8305 -> ../../md2 lrwxrwxrwx. 1 root root 9 Jun 15 23:50 scsi-SATA_OCZ-VERTEX3_OCZ-43DSRFTNCLE9ZJXX -> ../../sdb lrwxrwxrwx. 1 root root 10 Jun 15 23:50 scsi-SATA_OCZ-VERTEX3_OCZ-43DSRFTNCLE9ZJXX-part1 -> ../../sdb1 lrwxrwxrwx. 1 root root 9 Jun 15 23:50 scsi-SATA_ST3500413AS_5VMT49E3 -> ../../sdc lrwxrwxrwx. 1 root root 10 Jun 15 23:50 scsi-SATA_ST3500413AS_5VMT49E3-part1 -> ../../sdc1 lrwxrwxrwx. 1 root root 10 Jun 15 23:50 scsi-SATA_ST3500413AS_5VMT49E3-part2 -> ../../sdc2 lrwxrwxrwx. 1 root root 10 Jun 15 23:50 scsi-SATA_ST3500413AS_5VMT49E3-part3 -> ../../sdc3 lrwxrwxrwx. 1 root root 9 Jun 15 23:50 scsi-SATA_ST3500413AS_5VMTJNAJ -> ../../sda lrwxrwxrwx. 1 root root 10 Jun 15 23:50 scsi-SATA_ST3500413AS_5VMTJNAJ-part1 -> ../../sda1 lrwxrwxrwx. 1 root root 10 Jun 15 23:50 scsi-SATA_ST3500413AS_5VMTJNAJ-part2 -> ../../sda2 lrwxrwxrwx. 1 root root 10 Jun 15 23:50 scsi-SATA_ST3500413AS_5VMTJNAJ-part3 -> ../../sda3 lrwxrwxrwx. 1 root root 9 Jun 15 23:50 wwn-0x5000c500383621ff -> ../../sdc lrwxrwxrwx. 1 root root 10 Jun 15 23:50 wwn-0x5000c500383621ff-part1 -> ../../sdc1 lrwxrwxrwx. 1 root root 10 Jun 15 23:50 wwn-0x5000c500383621ff-part2 -> ../../sdc2 lrwxrwxrwx. 1 root root 10 Jun 15 23:50 wwn-0x5000c500383621ff-part3 -> ../../sdc3 lrwxrwxrwx. 1 root root 9 Jun 15 23:50 wwn-0x5000c5003838b2e7 -> ../../sda lrwxrwxrwx. 1 root root 10 Jun 15 23:50 wwn-0x5000c5003838b2e7-part1 -> ../../sda1 lrwxrwxrwx. 1 root root 10 Jun 15 23:50 wwn-0x5000c5003838b2e7-part2 -> ../../sda2 lrwxrwxrwx. 1 root root 10 Jun 15 23:50 wwn-0x5000c5003838b2e7-part3 -> ../../sda3 lrwxrwxrwx. 1 root root 9 Jun 15 23:50 wwn-0x5e83a97f592139d6 -> ../../sdb lrwxrwxrwx. 1 root root 10 Jun 15 23:50 wwn-0x5e83a97f592139d6-part1 -> ../../sdb1 # fdisk -l Disk /dev/sdb: 120.0 GB, 120034123776 bytes 255 heads, 63 sectors/track, 14593 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x79298ec9 Device Boot Start End Blocks Id System /dev/sdb1 1 14594 117219328 83 Linux Disk /dev/sdc: 500.1 GB, 500107862016 bytes 255 heads, 63 sectors/track, 60801 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x000d99de Device Boot Start End Blocks Id System /dev/sdc1 1 1275 10240000 fd Linux raid autodetect /dev/sdc2 * 1275 1339 512000 fd Linux raid autodetect /dev/sdc3 1339 60802 477633536 fd Linux raid autodetect Disk /dev/sda: 500.1 GB, 500107862016 bytes 255 heads, 63 sectors/track, 60801 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x000b3327 Device Boot Start End Blocks Id System /dev/sda1 1 1275 10240000 fd Linux raid autodetect /dev/sda2 * 1275 1339 512000 fd Linux raid autodetect /dev/sda3 1339 60802 477633536 fd Linux raid autodetect Disk /dev/md0: 10.5 GB, 10484641792 bytes 2 heads, 4 sectors/track, 2559727 cylinders Units = cylinders of 8 * 512 = 4096 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/md0 doesn't contain a valid partition table Disk /dev/md2: 489.1 GB, 489095557120 bytes 2 heads, 4 sectors/track, 119408095 cylinders Units = cylinders of 8 * 512 = 4096 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/md2 doesn't contain a valid partition table Disk /dev/md1: 524 MB, 524275712 bytes 2 heads, 4 sectors/track, 127997 cylinders Units = cylinders of 8 * 512 = 4096 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/md1 doesn't contain a valid partition table # cat /etc/grub.conf default=0 timeout=5 splashimage=(hd2,1)/grub/splash.xpm.gz hiddenmenu title CentOS (2.6.32-220.17.1.el6.x86_64) root (hd2,1) kernel /vmlinuz-2.6.32-220.17.1.el6.x86_64 ro root=UUID=967b4035-782d-4c66-b22f-50244fe970ca rd_MD_UUID=f403a2d0:447803b5:66edba73:569f8305 rd_MD_UUID=a22c43b9:f1954990:d3ddda5e:f9aff3c9 rd_NO_LUKS rd_NO_LVM rd_NO_DM LANG=en_US.UTF-8 SYSFONT=latarcyrheb-sun16 KEYBOARDTYPE=pc KEYTABLE=br-abnt2 crashkernel=auto rhgb quiet initrd /initramfs-2.6.32-220.17.1.el6.x86_64.img

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• Should I expose IObservable<T> on my interfaces?

  - by Alex

  My colleague and I have dispute. We are writing a .NET application that processes massive amounts of data. It receives data elements, groups subsets of them into blocks according to some criterion and processes those blocks. Let's say we have data items of type Foo arriving some source (from the network, for example) one by one. We wish to gather subsets of related objects of type Foo, construct an object of type Bar from each such subset and process objects of type Bar. One of us suggested the following design. Its main theme is exposing IObservable objects directly from the interfaces of our components. // ********* Interfaces ********** interface IFooSource { // this is the event-stream of objects of type Foo IObservable<Foo> FooArrivals { get; } } interface IBarSource { // this is the event-stream of objects of type Bar IObservable<Bar> BarArrivals { get; } } / ********* Implementations ********* class FooSource : IFooSource { // Here we put logic that receives Foo objects from the network and publishes them to the FooArrivals event stream. } class FooSubsetsToBarConverter : IBarSource { IFooSource fooSource; IObservable<Bar> BarArrivals { get { // Do some fancy Rx operators on fooSource.FooArrivals, like Buffer, Window, Join and others and return IObservable<Bar> } } } // this class will subscribe to the bar source and do processing class BarsProcessor { BarsProcessor(IBarSource barSource); void Subscribe(); } // ******************* Main ************************ class Program { public static void Main(string[] args) { var fooSource = FooSourceFactory.Create(); var barsProcessor = BarsProcessorFactory.Create(fooSource) // this will create FooSubsetToBarConverter and BarsProcessor barsProcessor.Subscribe(); fooSource.Run(); // this enters a loop of listening for Foo objects from the network and notifying about their arrival. } } The other suggested another design that its main theme is using our own publisher/subscriber interfaces and using Rx inside the implementations only when needed. //********** interfaces ********* interface IPublisher<T> { void Subscribe(ISubscriber<T> subscriber); } interface ISubscriber<T> { Action<T> Callback { get; } } //********** implementations ********* class FooSource : IPublisher<Foo> { public void Subscribe(ISubscriber<Foo> subscriber) { /* ... */ } // here we put logic that receives Foo objects from some source (the network?) publishes them to the registered subscribers } class FooSubsetsToBarConverter : ISubscriber<Foo>, IPublisher<Bar> { void Callback(Foo foo) { // here we put logic that aggregates Foo objects and publishes Bars when we have received a subset of Foos that match our criteria // maybe we use Rx here internally. } public void Subscribe(ISubscriber<Bar> subscriber) { /* ... */ } } class BarsProcessor : ISubscriber<Bar> { void Callback(Bar bar) { // here we put code that processes Bar objects } } //********** program ********* class Program { public static void Main(string[] args) { var fooSource = fooSourceFactory.Create(); var barsProcessor = barsProcessorFactory.Create(fooSource) // this will create BarsProcessor and perform all the necessary subscriptions fooSource.Run(); // this enters a loop of listening for Foo objects from the network and notifying about their arrival. } } Which one do you think is better? Exposing IObservable and making our components create new event streams from Rx operators, or defining our own publisher/subscriber interfaces and using Rx internally if needed? Here are some things to consider about the designs: In the first design the consumer of our interfaces has the whole power of Rx at his/her fingertips and can perform any Rx operators. One of us claims this is an advantage and the other claims that this is a drawback. The second design allows us to use any publisher/subscriber architecture under the hood. The first design ties us to Rx. If we wish to use the power of Rx, it requires more work in the second design because we need to translate the custom publisher/subscriber implementation to Rx and back. It requires writing glue code for every class that wishes to do some event processing.

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• Error 22 no such partition on adding a SSD

  - by Clodoaldo

  I'm trying to add a second SSD to a Centos 6 system. But I get the error 22 no such partition at boot. The system already has a single SSD (sdb) and a pair of HDDs (sd{a,c}) in a RAID 1 array from where it boots. It is as if the new SSD assumes one of the devices of the RAID array. Is it? How to avoid that or rearrange the setup? # cat fstab UUID=967b4035-782d-4c66-b22f-50244fe970ca / ext4 defaults 1 1 UUID=86fd06e9-cdc9-4166-ba9f-c237cfc43e02 /boot ext4 defaults 1 2 UUID=72552a7a-d8ae-4f0a-8917-b75a6239ce9f /ssd ext4 discard,relatime 1 2 UUID=8000e5e6-caa2-4765-94f8-9caeb2bda26e swap swap defaults 0 0 tmpfs /dev/shm tmpfs defaults 0 0 devpts /dev/pts devpts gid=5,mode=620 0 0 sysfs /sys sysfs defaults 0 0 proc /proc proc defaults 0 0 # ll /dev/disk/by-id/ total 0 lrwxrwxrwx. 1 root root 9 Jun 15 23:50 ata-OCZ-VERTEX3_OCZ-43DSRFTNCLE9ZJXX -> ../../sdb lrwxrwxrwx. 1 root root 10 Jun 15 23:50 ata-OCZ-VERTEX3_OCZ-43DSRFTNCLE9ZJXX-part1 -> ../../sdb1 lrwxrwxrwx. 1 root root 9 Jun 15 23:50 ata-ST3500413AS_5VMT49E3 -> ../../sdc lrwxrwxrwx. 1 root root 10 Jun 15 23:50 ata-ST3500413AS_5VMT49E3-part1 -> ../../sdc1 lrwxrwxrwx. 1 root root 10 Jun 15 23:50 ata-ST3500413AS_5VMT49E3-part2 -> ../../sdc2 lrwxrwxrwx. 1 root root 10 Jun 15 23:50 ata-ST3500413AS_5VMT49E3-part3 -> ../../sdc3 lrwxrwxrwx. 1 root root 9 Jun 15 23:50 ata-ST3500413AS_5VMTJNAJ -> ../../sda lrwxrwxrwx. 1 root root 10 Jun 15 23:50 ata-ST3500413AS_5VMTJNAJ-part1 -> ../../sda1 lrwxrwxrwx. 1 root root 10 Jun 15 23:50 ata-ST3500413AS_5VMTJNAJ-part2 -> ../../sda2 lrwxrwxrwx. 1 root root 10 Jun 15 23:50 ata-ST3500413AS_5VMTJNAJ-part3 -> ../../sda3 lrwxrwxrwx. 1 root root 9 Jun 15 23:50 md-name-localhost.localdomain:0 -> ../../md0 lrwxrwxrwx. 1 root root 9 Jun 15 23:50 md-name-localhost.localdomain:1 -> ../../md1 lrwxrwxrwx. 1 root root 9 Jun 15 23:50 md-name-localhost.localdomain:2 -> ../../md2 lrwxrwxrwx. 1 root root 9 Jun 15 23:50 md-uuid-a04d7241:8da6023e:f9004352:107a923a -> ../../md1 lrwxrwxrwx. 1 root root 9 Jun 15 23:50 md-uuid-a22c43b9:f1954990:d3ddda5e:f9aff3c9 -> ../../md0 lrwxrwxrwx. 1 root root 9 Jun 15 23:50 md-uuid-f403a2d0:447803b5:66edba73:569f8305 -> ../../md2 lrwxrwxrwx. 1 root root 9 Jun 15 23:50 scsi-SATA_OCZ-VERTEX3_OCZ-43DSRFTNCLE9ZJXX -> ../../sdb lrwxrwxrwx. 1 root root 10 Jun 15 23:50 scsi-SATA_OCZ-VERTEX3_OCZ-43DSRFTNCLE9ZJXX-part1 -> ../../sdb1 lrwxrwxrwx. 1 root root 9 Jun 15 23:50 scsi-SATA_ST3500413AS_5VMT49E3 -> ../../sdc lrwxrwxrwx. 1 root root 10 Jun 15 23:50 scsi-SATA_ST3500413AS_5VMT49E3-part1 -> ../../sdc1 lrwxrwxrwx. 1 root root 10 Jun 15 23:50 scsi-SATA_ST3500413AS_5VMT49E3-part2 -> ../../sdc2 lrwxrwxrwx. 1 root root 10 Jun 15 23:50 scsi-SATA_ST3500413AS_5VMT49E3-part3 -> ../../sdc3 lrwxrwxrwx. 1 root root 9 Jun 15 23:50 scsi-SATA_ST3500413AS_5VMTJNAJ -> ../../sda lrwxrwxrwx. 1 root root 10 Jun 15 23:50 scsi-SATA_ST3500413AS_5VMTJNAJ-part1 -> ../../sda1 lrwxrwxrwx. 1 root root 10 Jun 15 23:50 scsi-SATA_ST3500413AS_5VMTJNAJ-part2 -> ../../sda2 lrwxrwxrwx. 1 root root 10 Jun 15 23:50 scsi-SATA_ST3500413AS_5VMTJNAJ-part3 -> ../../sda3 lrwxrwxrwx. 1 root root 9 Jun 15 23:50 wwn-0x5000c500383621ff -> ../../sdc lrwxrwxrwx. 1 root root 10 Jun 15 23:50 wwn-0x5000c500383621ff-part1 -> ../../sdc1 lrwxrwxrwx. 1 root root 10 Jun 15 23:50 wwn-0x5000c500383621ff-part2 -> ../../sdc2 lrwxrwxrwx. 1 root root 10 Jun 15 23:50 wwn-0x5000c500383621ff-part3 -> ../../sdc3 lrwxrwxrwx. 1 root root 9 Jun 15 23:50 wwn-0x5000c5003838b2e7 -> ../../sda lrwxrwxrwx. 1 root root 10 Jun 15 23:50 wwn-0x5000c5003838b2e7-part1 -> ../../sda1 lrwxrwxrwx. 1 root root 10 Jun 15 23:50 wwn-0x5000c5003838b2e7-part2 -> ../../sda2 lrwxrwxrwx. 1 root root 10 Jun 15 23:50 wwn-0x5000c5003838b2e7-part3 -> ../../sda3 lrwxrwxrwx. 1 root root 9 Jun 15 23:50 wwn-0x5e83a97f592139d6 -> ../../sdb lrwxrwxrwx. 1 root root 10 Jun 15 23:50 wwn-0x5e83a97f592139d6-part1 -> ../../sdb1 # fdisk -l Disk /dev/sdb: 120.0 GB, 120034123776 bytes 255 heads, 63 sectors/track, 14593 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x79298ec9 Device Boot Start End Blocks Id System /dev/sdb1 1 14594 117219328 83 Linux Disk /dev/sdc: 500.1 GB, 500107862016 bytes 255 heads, 63 sectors/track, 60801 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x000d99de Device Boot Start End Blocks Id System /dev/sdc1 1 1275 10240000 fd Linux raid autodetect /dev/sdc2 * 1275 1339 512000 fd Linux raid autodetect /dev/sdc3 1339 60802 477633536 fd Linux raid autodetect Disk /dev/sda: 500.1 GB, 500107862016 bytes 255 heads, 63 sectors/track, 60801 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x000b3327 Device Boot Start End Blocks Id System /dev/sda1 1 1275 10240000 fd Linux raid autodetect /dev/sda2 * 1275 1339 512000 fd Linux raid autodetect /dev/sda3 1339 60802 477633536 fd Linux raid autodetect Disk /dev/md0: 10.5 GB, 10484641792 bytes 2 heads, 4 sectors/track, 2559727 cylinders Units = cylinders of 8 * 512 = 4096 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/md0 doesn't contain a valid partition table Disk /dev/md2: 489.1 GB, 489095557120 bytes 2 heads, 4 sectors/track, 119408095 cylinders Units = cylinders of 8 * 512 = 4096 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/md2 doesn't contain a valid partition table Disk /dev/md1: 524 MB, 524275712 bytes 2 heads, 4 sectors/track, 127997 cylinders Units = cylinders of 8 * 512 = 4096 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x00000000 Disk /dev/md1 doesn't contain a valid partition table # cat /etc/grub.conf default=0 timeout=5 splashimage=(hd2,1)/grub/splash.xpm.gz hiddenmenu title CentOS (2.6.32-220.17.1.el6.x86_64) root (hd2,1) kernel /vmlinuz-2.6.32-220.17.1.el6.x86_64 ro root=UUID=967b4035-782d-4c66-b22f-50244fe970ca rd_MD_UUID=f403a2d0:447803b5:66edba73:569f8305 rd_MD_UUID=a22c43b9:f1954990:d3ddda5e:f9aff3c9 rd_NO_LUKS rd_NO_LVM rd_NO_DM LANG=en_US.UTF-8 SYSFONT=latarcyrheb-sun16 KEYBOARDTYPE=pc KEYTABLE=br-abnt2 crashkernel=auto rhgb quiet initrd /initramfs-2.6.32-220.17.1.el6.x86_64.img

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• Duplication of Architecture State means physically extra?

  - by Doopy Doo

  Hyper-Threading Technology makes a single physical processor appear as two logical processors; the physical execution resources are shared and the architecture state is duplicated for the two logical processors. So, this means that there are two sets of basic registers such as Next Instruction Pointer, processor registers like AX, BX, CX etc physically embedded in the micro-processor chip, OR they(arch. state) are made to look two sets by some low level duplication by software/OS.

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• Server Vs Service / Physical Vs Virtual

  - by user559142

  When reading definitions for a server service (e.g. iis) you will often find that there are several cross references to a virtual server but none seem to definitively refer to the two as the same..... Can somebody help me to understand the differences - I cannot get my head around what the difference between each is? Ideally I would like to know the differences between the following/or indeed if any refer to the same... 1) Logical Server 2) Virtual Host 3) Logical Partition 4) Physical Server Vs Virtual Server 5) Server Service Vs Virtual Host

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• Create a primary partition on Windows 7

  - by TutorialPoint

  I have windows 7 installed. On the moment i have the following partitions on 1 hard disk: (300 GB) C: (Windows) (Primary, System, Boot, Page File, Crash Dump, Active) 100 GB D: (Data) (Logical) 100 GB E: (System Reserved created after Boot repair) (primary, system) 100 MB Now i want to create a new primary partition on this disk, because i have +/- 100 GB left, for a new OS. However when trying to make a new partition, it makes it a Logical partition, not Primary. How to make it primary...?

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• Simple Java calculator

  - by Kevin Duke

  Firstly this is not a homework question. I am practicing my knowledge on java. I figured a good way to do this is to write a simple program without help. Unfortunately, my compiler is telling me errors I don't know how to fix. Without changing much logic and code, could someone kindly point out where some of my errors are? Thanks import java.lang.*; import java.util.*; public class Calculator { private int solution; private int x; private int y; private char operators; public Calculator() { solution = 0; Scanner operators = new Scanner(System.in); Scanner operands = new Scanner(System.in); } public int addition(int x, int y) { return x + y; } public int subtraction(int x, int y) { return x - y; } public int multiplication(int x, int y) { return x * y; } public int division(int x, int y) { solution = x / y; return solution; } public void main (String[] args) { System.out.println("What operation? ('+', '-', '*', '/')"); System.out.println("Insert 2 numbers to be subtracted"); System.out.println("operand 1: "); x = operands; System.out.println("operand 2: "); y = operands.next(); switch(operators) { case('+'): addition(operands); operands.next(); break; case('-'): subtraction(operands); operands.next(); break; case('*'): multiplication(operands); operands.next(); break; case('/'): division(operands); operands.next(); break; } } }

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• SQL Azure server as unit of billing

  - by vtortola

  Hi, One of the azure training kit presentation says: Each account has zero or more logical servers Provisioned via a common portal Establishes a billing instrument Each logical server has one or more databases Contains metadata about database & usage Unit of authentication, geo-location, billing, reporting Generated DNS-based name Each database has standard SQL objects Users, Tables, Views, Indices, etc Unit of consistency So now I'm lost :D. Were not the databases themselves the units of billing? I mean, I thought that servers were just like logical containers and you were charged per number and size of databases. How servers are billed? Thanks.

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• PDF search on the iPhone

  - by pt2ph8

  After two days trying to read annotations from a PDF using Quartz, I've managed to do it and posted my code. Now I'd like to do the same for another frequently asked question: searching PDF documents with Quartz. Same situation as before, this question has been asked many times with almost no practical answers. So I need some pointers first, as I still haven't implemented this myself. What I tried: I tried using CGPDFScannerScan handling the TJ and Tj operators - returns the right text on some PDF, whereas on other documents it returns mostly random letters. Maybe it's related to text encoding? Someone pointed out that text blocks (marked by BT/ET operators) should be handled instead, but I still haven't managed to do so. Anyone managed to extract text from any PDF? After that, searching should be easy by storing all the text in a NSMutableString and using rangeOfString (if there's a better way please let me know). But then how to highlight the result? I know there are a few operators to find the glyph sizes, so I could calculate the resulting rect based on those values, but I've been reading the spec for hours... it's a bloated mess and I'm going insane. Anyone with a practical explanation? Thanks.

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• PTLQueue : a scalable bounded-capacity MPMC queue

  - by Dave

  Title: Fast concurrent MPMC queue -- I've used the following concurrent queue algorithm enough that it warrants a blog entry. I'll sketch out the design of a fast and scalable multiple-producer multiple-consumer (MPSC) concurrent queue called PTLQueue. The queue has bounded capacity and is implemented via a circular array. Bounded capacity can be a useful property if there's a mismatch between producer rates and consumer rates where an unbounded queue might otherwise result in excessive memory consumption by virtue of the container nodes that -- in some queue implementations -- are used to hold values. A bounded-capacity queue can provide flow control between components. Beware, however, that bounded collections can also result in resource deadlock if abused. The put() and take() operators are partial and wait for the collection to become non-full or non-empty, respectively. Put() and take() do not allocate memory, and are not vulnerable to the ABA pathologies. The PTLQueue algorithm can be implemented equally well in C/C++ and Java. Partial operators are often more convenient than total methods. In many use cases if the preconditions aren't met, there's nothing else useful the thread can do, so it may as well wait via a partial method. An exception is in the case of work-stealing queues where a thief might scan a set of queues from which it could potentially steal. Total methods return ASAP with a success-failure indication. (It's tempting to describe a queue or API as blocking or non-blocking instead of partial or total, but non-blocking is already an overloaded concurrency term. Perhaps waiting/non-waiting or patient/impatient might be better terms). It's also trivial to construct partial operators by busy-waiting via total operators, but such constructs may be less efficient than an operator explicitly and intentionally designed to wait. A PTLQueue instance contains an array of slots, where each slot has volatile Turn and MailBox fields. The array has power-of-two length allowing mod/div operations to be replaced by masking. We assume sensible padding and alignment to reduce the impact of false sharing. (On x86 I recommend 128-byte alignment and padding because of the adjacent-sector prefetch facility). Each queue also has PutCursor and TakeCursor cursor variables, each of which should be sequestered as the sole occupant of a cache line or sector. You can opt to use 64-bit integers if concerned about wrap-around aliasing in the cursor variables. Put(null) is considered illegal, but the caller or implementation can easily check for and convert null to a distinguished non-null proxy value if null happens to be a value you'd like to pass. Take() will accordingly convert the proxy value back to null. An advantage of PTLQueue is that you can use atomic fetch-and-increment for the partial methods. We initialize each slot at index I with (Turn=I, MailBox=null). Both cursors are initially 0. All shared variables are considered "volatile" and atomics such as CAS and AtomicFetchAndIncrement are presumed to have bidirectional fence semantics. Finally T is the templated type. I've sketched out a total tryTake() method below that allows the caller to poll the queue. tryPut() has an analogous construction. Zebra stripping : alternating row colors for nice-looking code listings. See also google code "prettify" : https://code.google.com/p/google-code-prettify/ Prettify is a javascript module that yields the HTML/CSS/JS equivalent of pretty-print. -- pre:nth-child(odd) { background-color:#ff0000; } pre:nth-child(even) { background-color:#0000ff; } border-left: 11px solid #ccc; margin: 1.7em 0 1.7em 0.3em; background-color:#BFB; font-size:12px; line-height:65%; " // PTLQueue : Put(v) : // producer : partial method - waits as necessary assert v != null assert Mask = 1 && (Mask & (Mask+1)) == 0 // Document invariants // doorway step // Obtain a sequence number -- ticket // As a practical concern the ticket value is temporally unique // The ticket also identifies and selects a slot auto tkt = AtomicFetchIncrement (&PutCursor, 1) slot * s = &Slots[tkt & Mask] // waiting phase : // wait for slot's generation to match the tkt value assigned to this put() invocation. // The "generation" is implicitly encoded as the upper bits in the cursor // above those used to specify the index : tkt div (Mask+1) // The generation serves as an epoch number to identify a cohort of threads // accessing disjoint slots while s-Turn != tkt : Pause assert s-MailBox == null s-MailBox = v // deposit and pass message Take() : // consumer : partial method - waits as necessary auto tkt = AtomicFetchIncrement (&TakeCursor,1) slot * s = &Slots[tkt & Mask] // 2-stage waiting : // First wait for turn for our generation // Acquire exclusive "take" access to slot's MailBox field // Then wait for the slot to become occupied while s-Turn != tkt : Pause // Concurrency in this section of code is now reduced to just 1 producer thread // vs 1 consumer thread. // For a given queue and slot, there will be most one Take() operation running // in this section. // Consumer waits for producer to arrive and make slot non-empty // Extract message; clear mailbox; advance Turn indicator // We have an obvious happens-before relation : // Put(m) happens-before corresponding Take() that returns that same "m" for T v = s-MailBox if v != null : s-MailBox = null ST-ST barrier s-Turn = tkt + Mask + 1 // unlock slot to admit next producer and consumer return v Pause tryTake() : // total method - returns ASAP with failure indication for auto tkt = TakeCursor slot * s = &Slots[tkt & Mask] if s-Turn != tkt : return null T v = s-MailBox // presumptive return value if v == null : return null // ratify tkt and v values and commit by advancing cursor if CAS (&TakeCursor, tkt, tkt+1) != tkt : continue s-MailBox = null ST-ST barrier s-Turn = tkt + Mask + 1 return v The basic idea derives from the Partitioned Ticket Lock "PTL" (US20120240126-A1) and the MultiLane Concurrent Bag (US8689237). The latter is essentially a circular ring-buffer where the elements themselves are queues or concurrent collections. You can think of the PTLQueue as a partitioned ticket lock "PTL" augmented to pass values from lock to unlock via the slots. Alternatively, you could conceptualize of PTLQueue as a degenerate MultiLane bag where each slot or "lane" consists of a simple single-word MailBox instead of a general queue. Each lane in PTLQueue also has a private Turn field which acts like the Turn (Grant) variables found in PTL. Turn enforces strict FIFO ordering and restricts concurrency on the slot mailbox field to at most one simultaneous put() and take() operation. PTL uses a single "ticket" variable and per-slot Turn (grant) fields while MultiLane has distinct PutCursor and TakeCursor cursors and abstract per-slot sub-queues. Both PTL and MultiLane advance their cursor and ticket variables with atomic fetch-and-increment. PTLQueue borrows from both PTL and MultiLane and has distinct put and take cursors and per-slot Turn fields. Instead of a per-slot queues, PTLQueue uses a simple single-word MailBox field. PutCursor and TakeCursor act like a pair of ticket locks, conferring "put" and "take" access to a given slot. PutCursor, for instance, assigns an incoming put() request to a slot and serves as a PTL "Ticket" to acquire "put" permission to that slot's MailBox field. To better explain the operation of PTLQueue we deconstruct the operation of put() and take() as follows. Put() first increments PutCursor obtaining a new unique ticket. That ticket value also identifies a slot. Put() next waits for that slot's Turn field to match that ticket value. This is tantamount to using a PTL to acquire "put" permission on the slot's MailBox field. Finally, having obtained exclusive "put" permission on the slot, put() stores the message value into the slot's MailBox. Take() similarly advances TakeCursor, identifying a slot, and then acquires and secures "take" permission on a slot by waiting for Turn. Take() then waits for the slot's MailBox to become non-empty, extracts the message, and clears MailBox. Finally, take() advances the slot's Turn field, which releases both "put" and "take" access to the slot's MailBox. Note the asymmetry : put() acquires "put" access to the slot, but take() releases that lock. At any given time, for a given slot in a PTLQueue, at most one thread has "put" access and at most one thread has "take" access. This restricts concurrency from general MPMC to 1-vs-1. We have 2 ticket locks -- one for put() and one for take() -- each with its own "ticket" variable in the form of the corresponding cursor, but they share a single "Grant" egress variable in the form of the slot's Turn variable. Advancing the PutCursor, for instance, serves two purposes. First, we obtain a unique ticket which identifies a slot. Second, incrementing the cursor is the doorway protocol step to acquire the per-slot mutual exclusion "put" lock. The cursors and operations to increment those cursors serve double-duty : slot-selection and ticket assignment for locking the slot's MailBox field. At any given time a slot MailBox field can be in one of the following states: empty with no pending operations -- neutral state; empty with one or more waiting take() operations pending -- deficit; occupied with no pending operations; occupied with one or more waiting put() operations -- surplus; empty with a pending put() or pending put() and take() operations -- transitional; or occupied with a pending take() or pending put() and take() operations -- transitional. The partial put() and take() operators can be implemented with an atomic fetch-and-increment operation, which may confer a performance advantage over a CAS-based loop. In addition we have independent PutCursor and TakeCursor cursors. Critically, a put() operation modifies PutCursor but does not access the TakeCursor and a take() operation modifies the TakeCursor cursor but does not access the PutCursor. This acts to reduce coherence traffic relative to some other queue designs. It's worth noting that slow threads or obstruction in one slot (or "lane") does not impede or obstruct operations in other slots -- this gives us some degree of obstruction isolation. PTLQueue is not lock-free, however. The implementation above is expressed with polite busy-waiting (Pause) but it's trivial to implement per-slot parking and unparking to deschedule waiting threads. It's also easy to convert the queue to a more general deque by replacing the PutCursor and TakeCursor cursors with Left/Front and Right/Back cursors that can move either direction. Specifically, to push and pop from the "left" side of the deque we would decrement and increment the Left cursor, respectively, and to push and pop from the "right" side of the deque we would increment and decrement the Right cursor, respectively. We used a variation of PTLQueue for message passing in our recent OPODIS 2013 paper. ul { list-style:none; padding-left:0; padding:0; margin:0; margin-left:0; } ul#myTagID { padding: 0px; margin: 0px; list-style:none; margin-left:0;} -- -- There's quite a bit of related literature in this area. I'll call out a few relevant references: Wilson's NYU Courant Institute UltraComputer dissertation from 1988 is classic and the canonical starting point : Operating System Data Structures for Shared-Memory MIMD Machines with Fetch-and-Add. Regarding provenance and priority, I think PTLQueue or queues effectively equivalent to PTLQueue have been independently rediscovered a number of times. See CB-Queue and BNPBV, below, for instance. But Wilson's dissertation anticipates the basic idea and seems to predate all the others. Gottlieb et al : Basic Techniques for the Efficient Coordination of Very Large Numbers of Cooperating Sequential Processors Orozco et al : CB-Queue in Toward high-throughput algorithms on many-core architectures which appeared in TACO 2012. Meneghin et al : BNPVB family in Performance evaluation of inter-thread communication mechanisms on multicore/multithreaded architecture Dmitry Vyukov : bounded MPMC queue (highly recommended) Alex Otenko : US8607249 (highly related). John Mellor-Crummey : Concurrent queues: Practical fetch-and-phi algorithms. Technical Report 229, Department of Computer Science, University of Rochester Thomasson : FIFO Distributed Bakery Algorithm (very similar to PTLQueue). Scott and Scherer : Dual Data Structures I'll propose an optimization left as an exercise for the reader. Say we wanted to reduce memory usage by eliminating inter-slot padding. Such padding is usually "dark" memory and otherwise unused and wasted. But eliminating the padding leaves us at risk of increased false sharing. Furthermore lets say it was usually the case that the PutCursor and TakeCursor were numerically close to each other. (That's true in some use cases). We might still reduce false sharing by incrementing the cursors by some value other than 1 that is not trivially small and is coprime with the number of slots. Alternatively, we might increment the cursor by one and mask as usual, resulting in a logical index. We then use that logical index value to index into a permutation table, yielding an effective index for use in the slot array. The permutation table would be constructed so that nearby logical indices would map to more distant effective indices. (Open question: what should that permutation look like? Possibly some perversion of a Gray code or De Bruijn sequence might be suitable). As an aside, say we need to busy-wait for some condition as follows : "while C == 0 : Pause". Lets say that C is usually non-zero, so we typically don't wait. But when C happens to be 0 we'll have to spin for some period, possibly brief. We can arrange for the code to be more machine-friendly with respect to the branch predictors by transforming the loop into : "if C == 0 : for { Pause; if C != 0 : break; }". Critically, we want to restructure the loop so there's one branch that controls entry and another that controls loop exit. A concern is that your compiler or JIT might be clever enough to transform this back to "while C == 0 : Pause". You can sometimes avoid this by inserting a call to a some type of very cheap "opaque" method that the compiler can't elide or reorder. On Solaris, for instance, you could use :"if C == 0 : { gethrtime(); for { Pause; if C != 0 : break; }}". It's worth noting the obvious duality between locks and queues. If you have strict FIFO lock implementation with local spinning and succession by direct handoff such as MCS or CLH,then you can usually transform that lock into a queue. Hidden commentary and annotations - invisible : * And of course there's a well-known duality between queues and locks, but I'll leave that topic for another blog post. * Compare and contrast : PTLQ vs PTL and MultiLane * Equivalent : Turn; seq; sequence; pos; position; ticket * Put = Lock; Deposit Take = identify and reserve slot; wait; extract & clear; unlock * conceptualize : Distinct PutLock and TakeLock implemented as ticket lock or PTL Distinct arrival cursors but share per-slot "Turn" variable provides exclusive role-based access to slot's mailbox field put() acquires exclusive access to a slot for purposes of "deposit" assigns slot round-robin and then acquires deposit access rights/perms to that slot take() acquires exclusive access to slot for purposes of "withdrawal" assigns slot round-robin and then acquires withdrawal access rights/perms to that slot At any given time, only one thread can have withdrawal access to a slot at any given time, only one thread can have deposit access to a slot Permissible for T1 to have deposit access and T2 to simultaneously have withdrawal access * round-robin for the purposes of; role-based; access mode; access role mailslot; mailbox; allocate/assign/identify slot rights; permission; license; access permission; * PTL/Ticket hybrid Asymmetric usage ; owner oblivious lock-unlock pairing K-exclusion add Grant cursor pass message m from lock to unlock via Slots[] array Cursor performs 2 functions : + PTL ticket + Assigns request to slot in round-robin fashion Deconstruct protocol : explication put() : allocate slot in round-robin fashion acquire PTL for "put" access store message into slot associated with PTL index take() : Acquire PTL for "take" access // doorway step seq = fetchAdd (&Grant, 1) s = &Slots[seq & Mask] // waiting phase while s-Turn != seq : pause Extract : wait for s-mailbox to be full v = s-mailbox s-mailbox = null Release PTL for both "put" and "take" access s-Turn = seq + Mask + 1 * Slot round-robin assignment and lock "doorway" protocol leverage the same cursor and FetchAdd operation on that cursor FetchAdd (&Cursor,1) + round-robin slot assignment and dispersal + PTL/ticket lock "doorway" step waiting phase is via "Turn" field in slot * PTLQueue uses 2 cursors -- put and take. Acquire "put" access to slot via PTL-like lock Acquire "take" access to slot via PTL-like lock 2 locks : put and take -- at most one thread can access slot's mailbox Both locks use same "turn" field Like multilane : 2 cursors : put and take slot is simple 1-capacity mailbox instead of queue Borrow per-slot turn/grant from PTL Provides strict FIFO Lock slot : put-vs-put take-vs-take at most one put accesses slot at any one time at most one put accesses take at any one time reduction to 1-vs-1 instead of N-vs-M concurrency Per slot locks for put/take Release put/take by advancing turn * is instrumental in ... * P-V Semaphore vs lock vs K-exclusion * See also : FastQueues-excerpt.java dice-etc/queue-mpmc-bounded-blocking-circular-xadd/ * PTLQueue is the same as PTLQB - identical * Expedient return; ASAP; prompt; immediately * Lamport's Bakery algorithm : doorway step then waiting phase Threads arriving at doorway obtain a unique ticket number Threads enter in ticket order * In the terminology of Reed and Kanodia a ticket lock corresponds to the busy-wait implementation of a semaphore using an eventcount and a sequencer It can also be thought of as an optimization of Lamport's bakery lock was designed for fault-tolerance rather than performance Instead of spinning on the release counter, processors using a bakery lock repeatedly examine the tickets of their peers --

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• Making Sense of ASP.NET Paths

  - by Rick Strahl

  ASP.Net includes quite a plethora of properties to retrieve path information about the current request, control and application. There's a ton of information available about paths on the Request object, some of it appearing to overlap and some of it buried several levels down, and it can be confusing to find just the right path that you are looking for. To keep things straight I thought it a good idea to summarize the path options along with descriptions and example paths. I wrote a post about this a long time ago in 2004 and I find myself frequently going back to that page to quickly figure out which path I’m looking for in processing the current URL. Apparently a lot of people must be doing the same, because the original post is the second most visited even to this date on this blog to the tune of nearly 500 hits per day. So, I decided to update and expand a bit on the original post with a little more information and clarification based on the original comments. Request Object Paths Available Here's a list of the Path related properties on the Request object (and the Page object). Assume a path like http://www.west-wind.com/webstore/admin/paths.aspx for the paths below where webstore is the name of the virtual. .blackborder td { border-bottom: solid 1px silver; border-left: solid 1px silver; } Request Property Description and Value ApplicationPath Returns the web root-relative logical path to the virtual root of this app. /webstore/ PhysicalApplicationPath Returns local file system path of the virtual root for this app. c:\inetpub\wwwroot\webstore PhysicalPath Returns the local file system path to the current script or path. c:\inetpub\wwwroot\webstore\admin\paths.aspx Path FilePath CurrentExecutionFilePath All of these return the full root relative logical path to the script page including path and scriptname. CurrentExcecutionFilePath will return the ‘current’ request path after a Transfer/Execute call while FilePath will always return the original request’s path. /webstore/admin/paths.aspx AppRelativeCurrentExecutionFilePath Returns an ASP.NET root relative virtual path to the script or path for the current request. If in  a Transfer/Execute call the transferred Path is returned. ~/admin/paths.aspx PathInfo Returns any extra path following the script name. If no extra path is provided returns the root-relative path (returns text in red below). string.Empty if no PathInfo is available. /webstore/admin/paths.aspx/ExtraPathInfo RawUrl Returns the full root relative URL including querystring and extra path as a string. /webstore/admin/paths.aspx?sku=wwhelp40 Url Returns a fully qualified URL including querystring and extra path. Note this is a Uri instance rather than string. http://www.west-wind.com/webstore/admin/paths.aspx?sku=wwhelp40 UrlReferrer The fully qualified URL of the page that sent the request. This is also a Uri instance and this value is null if the page was directly accessed by typing into the address bar or using an HttpClient based Referrer client Http header. http://www.west-wind.com/webstore/default.aspx?Info Control.TemplateSourceDirectory Returns the logical path to the folder of the page, master or user control on which it is called. This is useful if you need to know the path only to a Page or control from within the control. For non-file controls this returns the Page path. /webstore/admin/ As you can see there’s a ton of information available there for each of the three common path formats: Physical Path is an OS type path that points to a path or file on disk. Logical Path is a Web path that is relative to the Web server’s root. It includes the virtual plus the application relative path. ~/ (Root-relative) Path is an ASP.NET specific path that includes ~/ to indicate the virtual root Web path. ASP.NET can convert virtual paths into either logical paths using Control.ResolveUrl(), or physical paths using Server.MapPath(). Root relative paths are useful for specifying portable URLs that don’t rely on relative directory structures and very useful from within control or component code. You should be able to get any necessary format from ASP.NET from just about any path or script using these mechanisms. ~/ Root Relative Paths and ResolveUrl() and ResolveClientUrl() ASP.NET supports root-relative virtual path syntax in most of its URL properties in Web Forms. So you can easily specify a root relative path in a control rather than a location relative path: <asp:Image runat="server" ID="imgHelp" ImageUrl="~/images/help.gif" /> ASP.NET internally resolves this URL by using ResolveUrl("~/images/help.gif") to arrive at the root-relative URL of /webstore/images/help.gif which uses the Request.ApplicationPath as the basepath to replace the ~. By convention any custom Web controls also should use ResolveUrl() on URL properties to provide the same functionality. In your own code you can use Page.ResolveUrl() or Control.ResolveUrl() to accomplish the same thing: string imgPath = this.ResolveUrl("~/images/help.gif"); imgHelp.ImageUrl = imgPath; Unfortunately ResolveUrl() is limited to WebForm pages, so if you’re in an HttpHandler or Module it’s not available. ASP.NET Mvc also has it’s own more generic version of ResolveUrl in Url.Decode: <script src="<%= Url.Content("~/scripts/new.js") %>" type="text/javascript"></script> which is part of the UrlHelper class. In ASP.NET MVC the above sort of syntax is actually even more crucial than in WebForms due to the fact that views are not referencing specific pages but rather are often path based which can lead to various variations on how a particular view is referenced. In a Module or Handler code Control.ResolveUrl() unfortunately is not available which in retrospect seems like an odd design choice – URL resolution really should happen on a Request basis not as part of the Page framework. Luckily you can also rely on the static VirtualPathUtility class: string path = VirtualPathUtility.ToAbsolute("~/admin/paths.aspx"); VirtualPathUtility also many other quite useful methods for dealing with paths and converting between the various kinds of paths supported. One thing to watch out for is that ToAbsolute() will throw an exception if a query string is provided and doesn’t work on fully qualified URLs. I wrote about this topic with a custom solution that works fully qualified URLs and query strings here (check comments for some interesting discussions too). Similar to ResolveUrl() is ResolveClientUrl() which creates a fully qualified HTTP path that includes the protocol and domain name. It’s rare that this full resolution is needed but can be useful in some scenarios. Mapping Virtual Paths to Physical Paths with Server.MapPath() If you need to map root relative or current folder relative URLs to physical URLs or you can use HttpContext.Current.Server.MapPath(). Inside of a Page you can do the following: string physicalPath = Server.MapPath("~/scripts/ww.jquery.js")); MapPath is pretty flexible and it understands both ASP.NET style virtual paths as well as plain relative paths, so the following also works. string physicalPath = Server.MapPath("scripts/silverlight.js"); as well as dot relative syntax: string physicalPath = Server.MapPath("../scripts/jquery.js"); Once you have the physical path you can perform standard System.IO Path and File operations on the file. Remember with physical paths and IO or copy operations you need to make sure you have permissions to access files and folders based on the Web server user account that is active (NETWORK SERVICE, ASPNET typically). Note the Server.MapPath will not map up beyond the virtual root of the application for security reasons. Server and Host Information Between these settings you can get all the information you may need to figure out where you are at and to build new Url if necessary. If you need to build a URL completely from scratch you can get access to information about the server you are accessing: Server Variable Function and Example SERVER_NAME The of the domain or IP Address wwww.west-wind.com or 127.0.0.1 SERVER_PORT The port that the request runs under. 80 SERVER_PORT_SECURE Determines whether https: was used. 0 or 1 APPL_MD_PATH ADSI DirectoryServices path to the virtual root directory. Note that LM typically doesn’t work for ADSI access so you should replace that with LOCALHOST or the machine’s NetBios name. /LM/W3SVC/1/ROOT/webstore Request.Url and Uri Parsing If you still need more control over the current request URL or  you need to create new URLs from an existing one, the current Request.Url Uri property offers a lot of control. Using the Uri class and UriBuilder makes it easy to retrieve parts of a URL and create new URLs based on existing URL. The UriBuilder class is the preferred way to create URLs – much preferable over creating URIs via string concatenation. Uri Property Function Scheme The URL scheme or protocol prefix. http or https Port The port if specifically specified. DnsSafeHost The domain name or local host NetBios machine name www.west-wind.com or rasnote LocalPath The full path of the URL including script name and extra PathInfo. /webstore/admin/paths.aspx Query The query string if any ?id=1 The Uri class itself is great for retrieving Uri parts, but most of the properties are read only if you need to modify a URL in order to change it you can use the UriBuilder class to load up an existing URL and modify it to create a new one. Here are a few common operations I’ve needed to do to get specific URLs: Convert the Request URL to an SSL/HTTPS link For example to take the current request URL and converted  it to a secure URL can be done like this: UriBuilder build = new UriBuilder(Request.Url); build.Scheme = "https"; build.Port = -1; // don't inject port Uri newUri = build.Uri; string newUrl = build.ToString(); Retrieve the fully qualified URL without a QueryString AFAIK, there’s no native routine to retrieve the current request URL without the query string. It’s easy to do with UriBuilder however: UriBuilder builder = newUriBuilder(Request.Url); builder.Query = ""; stringlogicalPathWithoutQuery = builder.ToString(); What else? I took a look through the old post’s comments and addressed as many of the questions and comments that came up in there. With a few small and silly exceptions this update post handles most of these. But I’m sure there are a more things that go in here. What else would be useful to put onto this post so it serves as a nice all in one place to go for path references? If you think of something leave a comment and I’ll try to update the post with it in the future.© Rick Strahl, West Wind Technologies, 2005-2010Posted in ASP.NET  

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• Understanding and Controlling Parallel Query Processing in SQL Server

  Data warehousing and general reporting applications tend to be CPU intensive because they need to read and process a large number of rows. To facilitate quick data processing for queries that touch a large amount of data, Microsoft SQL Server exploits the power of multiple logical processors to provide parallel query processing operations such as parallel scans. Through extensive testing, we have learned that, for most large queries that are executed in a parallel fashion, SQL Server can deliver linear or nearly linear response time speedup as the number of logical processors increases. However, some queries in high parallelism scenarios perform suboptimally. There are also some parallelism issues that can occur in a multi-user parallel query workload. This white paper describes parallel performance problems you might encounter when you run such queries and workloads, and it explains why these issues occur. In addition, it presents how data warehouse developers can detect these issues, and how they can work around them or mitigate them.

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• Installation doesn't detect existing partitions

  - by retrac1324

  I am trying to install Ubuntu 11.10 in a dual boot with my existing Windows 7 but the installer does not detect any existing partitions. I have tried resetting my BCD using EasyBCD and doing fixmbr from the Windows startup disc. A while ago I had to use TestDisk to recover my partition table so this might be the cause but I have installed Ubuntu and Windows many times before with no problems. fdisk -l output: Disk /dev/sda: 640.1 GB, 640135028736 bytes 255 heads, 63 sectors/track, 77825 cylinders, total 1250263728 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: 0x360555e5 Device Boot Start End Blocks Id System /dev/sda1 * 2048 1250274689 625136321 7 HPFS/NTFS/exFAT Disk /dev/sdf: 7803 MB, 7803174912 bytes 255 heads, 63 sectors/track, 948 cylinders, total 15240576 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: 0x6f795a8d Device Boot Start End Blocks Id System /dev/sdf1 * 63 15240575 7620256+ c W95 FAT32 (LBA)

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• Unable to boot Windows 7 after installing Ubuntu

  - by Devendra

  I have Windows 7 on my machine and then installed Ubuntu 12.04 using a live CD. I can see both Windows 7 and Ubuntu in the grub menu, but when I select Windows 7 it shows a black screen for about 2 seconds and the returns to the Grub menu. But if I select Ubuntu it's working fine. This is the contents of the boot-repair log: Boot Info Script 0.61.full + Boot-Repair extra info [Boot-Info November 20th 2012] ============================= Boot Info Summary: =============================== => Grub2 (v2.00) is installed in the MBR of /dev/sda and looks at sector 1 of the same hard drive for core.img. core.img is at this location and looks in partition 1 for (,msdos6)/boot/grub. sda1: __________________________________________________________________________ File system: ntfs Boot sector type: Grub2 (v1.99-2.00) Boot sector info: Grub2 (v2.00) is installed in the boot sector of sda1 and looks at sector 388911128 of the same hard drive for core.img. core.img is at this location and looks in partition 1 for (,msdos6)/boot/grub. No errors found in the Boot Parameter Block. Operating System: Windows 7 Boot files: /bootmgr /Boot/BCD /Windows/System32/winload.exe sda2: __________________________________________________________________________ File system: ntfs Boot sector type: Windows Vista/7: NTFS Boot sector info: No errors found in the Boot Parameter Block. Operating System: Boot files: sda3: __________________________________________________________________________ File system: ntfs Boot sector type: Windows Vista/7: NTFS Boot sector info: No errors found in the Boot Parameter Block. Operating System: Boot files: sda4: __________________________________________________________________________ File system: Extended Partition Boot sector type: - Boot sector info: sda5: __________________________________________________________________________ File system: ntfs Boot sector type: Windows Vista/7: NTFS Boot sector info: According to the info in the boot sector, sda5 starts at sector 2048. Operating System: Boot files: sda6: __________________________________________________________________________ File system: ext4 Boot sector type: - Boot sector info: Operating System: Ubuntu 12.10 Boot files: /boot/grub/grub.cfg /etc/fstab /boot/grub/i386-pc/core.img sda7: __________________________________________________________________________ File system: swap Boot sector type: - Boot sector info: ============================ Drive/Partition Info: ============================= Drive: sda _____________________________________________________________________ Disk /dev/sda: 750.2 GB, 750156374016 bytes 255 heads, 63 sectors/track, 91201 cylinders, total 1465149168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes Partition Boot Start Sector End Sector # of Sectors Id System /dev/sda1 * 206,848 146,802,687 146,595,840 7 NTFS / exFAT / HPFS /dev/sda2 147,007,488 293,623,807 146,616,320 7 NTFS / exFAT / HPFS /dev/sda3 293,623,808 332,820,613 39,196,806 7 NTFS / exFAT / HPFS /dev/sda4 332,822,526 1,465,145,343 1,132,322,818 f W95 Extended (LBA) /dev/sda5 461,342,720 1,465,145,343 1,003,802,624 7 NTFS / exFAT / HPFS /dev/sda6 332,822,528 453,171,199 120,348,672 83 Linux /dev/sda7 453,173,248 461,338,623 8,165,376 82 Linux swap / Solaris "blkid" output: ________________________________________________________________ Device UUID TYPE LABEL /dev/sda1 F6AE2C13AE2BCB47 ntfs /dev/sda2 DC2273012272DFC6 ntfs /dev/sda3 1E76E43376E40D79 ntfs New Volume /dev/sda5 5ED60ACDD60AA57D ntfs /dev/sda6 9e70fd16-b48b-4f88-adcf-e443aef83124 ext4 /dev/sda7 52f3dd94-6be7-4a7b-a3ae-f43eb8810483 swap ================================ Mount points: ================================= Device Mount_Point Type Options /dev/sda6 / ext4 (rw,errors=remount-ro) =========================== sda6/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 $prefix/grubenv ]; then set have_grubenv=true load_env fi set default="0" if [ x"${feature_menuentry_id}" = xy ]; then menuentry_id_option="--id" else menuentry_id_option="" fi export menuentry_id_option 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 { if [ x$feature_all_video_module = xy ]; then insmod all_video else insmod efi_gop insmod efi_uga insmod ieee1275_fb insmod vbe insmod vga insmod video_bochs insmod video_cirrus fi } if [ x$feature_default_font_path = xy ] ; then font=unicode else insmod part_msdos insmod ext2 set root='hd0,msdos6' if [ x$feature_platform_search_hint = xy ]; then search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos6 --hint-efi=hd0,msdos6 --hint-baremetal=ahci0,msdos6 9e70fd16-b48b-4f88-adcf-e443aef83124 else search --no-floppy --fs-uuid --set=root 9e70fd16-b48b-4f88-adcf-e443aef83124 fi font="/usr/share/grub/unicode.pf2" fi if loadfont $font ; then set gfxmode=auto load_video insmod gfxterm set locale_dir=$prefix/locale set lang=en_IN insmod gettext fi terminal_output gfxterm if [ "${recordfail}" = 1 ]; then set timeout=10 else set timeout=10 fi ### END /etc/grub.d/00_header ### ### BEGIN /etc/grub.d/05_debian_theme ### set menu_color_normal=white/black set menu_color_highlight=black/light-gray if background_color 44,0,30; then clear fi ### END /etc/grub.d/05_debian_theme ### ### BEGIN /etc/grub.d/10_linux ### function gfxmode { set gfxpayload="${1}" if [ "${1}" = "keep" ]; then set vt_handoff=vt.handoff=7 else set vt_handoff= fi } if [ "${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' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-simple-9e70fd16-b48b-4f88-adcf-e443aef83124' { recordfail gfxmode $linux_gfx_mode insmod gzio insmod part_msdos insmod ext2 set root='hd0,msdos6' if [ x$feature_platform_search_hint = xy ]; then search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos6 --hint-efi=hd0,msdos6 --hint-baremetal=ahci0,msdos6 9e70fd16-b48b-4f88-adcf-e443aef83124 else search --no-floppy --fs-uuid --set=root 9e70fd16-b48b-4f88-adcf-e443aef83124 fi linux /boot/vmlinuz-3.5.0-17-generic root=UUID=9e70fd16-b48b-4f88-adcf-e443aef83124 ro quiet splash $vt_handoff initrd /boot/initrd.img-3.5.0-17-generic } submenu 'Advanced options for Ubuntu' $menuentry_id_option 'gnulinux-advanced-9e70fd16-b48b-4f88-adcf-e443aef83124' { menuentry 'Ubuntu, with Linux 3.5.0-17-generic' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-3.5.0-17-generic-advanced-9e70fd16-b48b-4f88-adcf-e443aef83124' { recordfail gfxmode $linux_gfx_mode insmod gzio insmod part_msdos insmod ext2 set root='hd0,msdos6' if [ x$feature_platform_search_hint = xy ]; then search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos6 --hint-efi=hd0,msdos6 --hint-baremetal=ahci0,msdos6 9e70fd16-b48b-4f88-adcf-e443aef83124 else search --no-floppy --fs-uuid --set=root 9e70fd16-b48b-4f88-adcf-e443aef83124 fi echo 'Loading Linux 3.5.0-17-generic ...' linux /boot/vmlinuz-3.5.0-17-generic root=UUID=9e70fd16-b48b-4f88-adcf-e443aef83124 ro quiet splash $vt_handoff echo 'Loading initial ramdisk ...' initrd /boot/initrd.img-3.5.0-17-generic } menuentry 'Ubuntu, with Linux 3.5.0-17-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-3.5.0-17-generic-recovery-9e70fd16-b48b-4f88-adcf-e443aef83124' { recordfail insmod gzio insmod part_msdos insmod ext2 set root='hd0,msdos6' if [ x$feature_platform_search_hint = xy ]; then search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos6 --hint-efi=hd0,msdos6 --hint-baremetal=ahci0,msdos6 9e70fd16-b48b-4f88-adcf-e443aef83124 else search --no-floppy --fs-uuid --set=root 9e70fd16-b48b-4f88-adcf-e443aef83124 fi echo 'Loading Linux 3.5.0-17-generic ...' linux /boot/vmlinuz-3.5.0-17-generic root=UUID=9e70fd16-b48b-4f88-adcf-e443aef83124 ro recovery nomodeset echo 'Loading initial ramdisk ...' initrd /boot/initrd.img-3.5.0-17-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' if [ x$feature_platform_search_hint = xy ]; then search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos6 --hint-efi=hd0,msdos6 --hint-baremetal=ahci0,msdos6 9e70fd16-b48b-4f88-adcf-e443aef83124 else search --no-floppy --fs-uuid --set=root 9e70fd16-b48b-4f88-adcf-e443aef83124 fi linux16 /boot/memtest86+.bin } menuentry "Memory test (memtest86+, serial console 115200)" { insmod part_msdos insmod ext2 set root='hd0,msdos6' if [ x$feature_platform_search_hint = xy ]; then search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos6 --hint-efi=hd0,msdos6 --hint-baremetal=ahci0,msdos6 9e70fd16-b48b-4f88-adcf-e443aef83124 else search --no-floppy --fs-uuid --set=root 9e70fd16-b48b-4f88-adcf-e443aef83124 fi linux16 /boot/memtest86+.bin console=ttyS0,115200n8 } ### END /etc/grub.d/20_memtest86+ ### ### BEGIN /etc/grub.d/30_os-prober ### menuentry 'Windows 7 (loader) (on /dev/sda1)' --class windows --class os $menuentry_id_option 'osprober-chain-F6AE2C13AE2BCB47' { insmod part_msdos insmod ntfs set root='hd0,msdos1' if [ x$feature_platform_search_hint = xy ]; then search --no-floppy --fs-uuid --set=root --hint-bios=hd0,msdos1 --hint-efi=hd0,msdos1 --hint-baremetal=ahci0,msdos1 F6AE2C13AE2BCB47 else search --no-floppy --fs-uuid --set=root F6AE2C13AE2BCB47 fi chainloader +1 } ### END /etc/grub.d/30_os-prober ### ### BEGIN /etc/grub.d/30_uefi-firmware ### ### END /etc/grub.d/30_uefi-firmware ### ### 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 ${config_directory}/custom.cfg ]; then source ${config_directory}/custom.cfg elif [ -z "${config_directory}" -a -f $prefix/custom.cfg ]; then source $prefix/custom.cfg; fi ### END /etc/grub.d/41_custom ### -------------------------------------------------------------------------------- =============================== sda6/etc/fstab: ================================ -------------------------------------------------------------------------------- # /etc/fstab: static file system information. # # Use 'blkid' to print the universally unique identifier for a # device; this may be used with UUID= as a more robust way to name devices # that works even if disks are added and removed. See fstab(5). # # <file system> <mount point> <type> <options> <dump> <pass> # / was on /dev/sda6 during installation UUID=9e70fd16-b48b-4f88-adcf-e443aef83124 / ext4 errors=remount-ro 0 1 # swap was on /dev/sda7 during installation UUID=52f3dd94-6be7-4a7b-a3ae-f43eb8810483 none swap sw 0 0 -------------------------------------------------------------------------------- =================== sda6: Location of files loaded by Grub: ==================== GiB - GB File Fragment(s) 162.831275940 = 174.838751232 boot/grub/grub.cfg 1 163.036647797 = 175.059267584 boot/initrd.img-3.5.0-17-generic 1 206.871749878 = 222.126850048 boot/vmlinuz-3.5.0-17-generic 1 163.036647797 = 175.059267584 initrd.img 1 163.036647797 = 175.059267584 initrd.img.old 1 206.871749878 = 222.126850048 vmlinuz 1 =============================== StdErr Messages: =============================== cat: write error: Broken pipe cat: write error: Broken pipe ADDITIONAL INFORMATION : =================== log of boot-repair 2012-12-11__00h59 =================== boot-repair version : 3.195~ppa28~quantal boot-sav version : 3.195~ppa28~quantal glade2script version : 3.2.2~ppa45~quantal boot-sav-extra version : 3.195~ppa28~quantal boot-repair is executed in installed-session (Ubuntu 12.10, quantal, Ubuntu, x86_64) CPU op-mode(s): 32-bit, 64-bit BOOT_IMAGE=/boot/vmlinuz-3.5.0-17-generic root=UUID=9e70fd16-b48b-4f88-adcf-e443aef83124 ro quiet splash vt.handoff=7 =================== os-prober: /dev/sda6:The OS now in use - Ubuntu 12.10 CurrentSession:linux /dev/sda1:Windows 7 (loader):Windows:chain =================== blkid: /dev/sda1: UUID="F6AE2C13AE2BCB47" TYPE="ntfs" /dev/sda2: UUID="DC2273012272DFC6" TYPE="ntfs" /dev/sda3: LABEL="New Volume" UUID="1E76E43376E40D79" TYPE="ntfs" /dev/sda5: UUID="5ED60ACDD60AA57D" TYPE="ntfs" /dev/sda6: UUID="9e70fd16-b48b-4f88-adcf-e443aef83124" TYPE="ext4" /dev/sda7: UUID="52f3dd94-6be7-4a7b-a3ae-f43eb8810483" TYPE="swap" 1 disks with OS, 2 OS : 1 Linux, 0 MacOS, 1 Windows, 0 unknown type OS. Warning: extended partition does not start at a cylinder boundary. DOS and Linux will interpret the contents differently. =================== /etc/default/grub : # If you change this file, run 'update-grub' afterwards to update # /boot/grub/grub.cfg. # For full documentation of the options in this file, see: # info -f grub -n 'Simple configuration' GRUB_DEFAULT=0 #GRUB_HIDDEN_TIMEOUT=0 GRUB_HIDDEN_TIMEOUT_QUIET=true GRUB_TIMEOUT=10 GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian` GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" GRUB_CMDLINE_LINUX="" # Uncomment to enable BadRAM filtering, modify to suit your needs # This works with Linux (no patch required) and with any kernel that obtains # the memory map information from GRUB (GNU Mach, kernel of FreeBSD ...) #GRUB_BADRAM="0x01234567,0xfefefefe,0x89abcdef,0xefefefef" # Uncomment to disable graphical terminal (grub-pc only) #GRUB_TERMINAL=console # The resolution used on graphical terminal # note that you can use only modes which your graphic card supports via VBE # you can see them in real GRUB with the command `vbeinfo' #GRUB_GFXMODE=640x480 # Uncomment if you don't want GRUB to pass "root=UUID=xxx" parameter to Linux #GRUB_DISABLE_LINUX_UUID=true # Uncomment to disable generation of recovery mode menu entries #GRUB_DISABLE_RECOVERY="true" # Uncomment to get a beep at grub start #GRUB_INIT_TUNE="480 440 1" =================== /etc/grub.d/ : drwxr-xr-x 2 root root 4096 Oct 17 20:29 grub.d total 72 -rwxr-xr-x 1 root root 7541 Oct 14 23:06 00_header -rwxr-xr-x 1 root root 5488 Oct 4 15:00 05_debian_theme -rwxr-xr-x 1 root root 10891 Oct 14 23:06 10_linux -rwxr-xr-x 1 root root 10258 Oct 14 23:06 20_linux_xen -rwxr-xr-x 1 root root 1688 Oct 11 19:40 20_memtest86+ -rwxr-xr-x 1 root root 10976 Oct 14 23:06 30_os-prober -rwxr-xr-x 1 root root 1426 Oct 14 23:06 30_uefi-firmware -rwxr-xr-x 1 root root 214 Oct 14 23:06 40_custom -rwxr-xr-x 1 root root 216 Oct 14 23:06 41_custom -rw-r--r-- 1 root root 483 Oct 14 23:06 README =================== UEFI/Legacy mode: This installed-session is not in EFI-mode. EFI in dmesg. Please report this message to [email protected] [ 0.000000] ACPI: UEFI 00000000bafe7000 0003E (v01 DELL QA09 00000002 PTL 00000002) [ 0.000000] ACPI: UEFI 00000000bafe6000 00042 (v01 PTL COMBUF 00000001 PTL 00000001) [ 0.000000] ACPI: UEFI 00000000bafe3000 00256 (v01 DELL QA09 00000002 PTL 00000002) SecureBoot disabled. =================== PARTITIONS & DISKS: sda6 : sda, not-sepboot, grubenv-ok grub2, grub-pc , update-grub, 64, with-boot, is-os, not--efi--part, fstab-without-boot, fstab-without-efi, no-nt, no-winload, no-recov-nor-hid, no-bmgr, notwinboot, apt-get, grub-install, with--usr, fstab-without-usr, not-sep-usr, standard, farbios, . sda1 : sda, not-sepboot, no-grubenv nogrub, no-docgrub, no-update-grub, 32, no-boot, is-os, not--efi--part, part-has-no-fstab, part-has-no-fstab, no-nt, haswinload, no-recov-nor-hid, bootmgr, is-winboot, nopakmgr, nogrubinstall, no---usr, part-has-no-fstab, not-sep-usr, standard, not-far, /mnt/boot-sav/sda1. sda2 : sda, not-sepboot, no-grubenv nogrub, no-docgrub, no-update-grub, 32, no-boot, no-os, not--efi--part, part-has-no-fstab, part-has-no-fstab, no-nt, no-winload, no-recov-nor-hid, no-bmgr, notwinboot, nopakmgr, nogrubinstall, no---usr, part-has-no-fstab, not-sep-usr, standard, farbios, /mnt/boot-sav/sda2. sda3 : sda, not-sepboot, no-grubenv nogrub, no-docgrub, no-update-grub, 32, no-boot, no-os, not--efi--part, part-has-no-fstab, part-has-no-fstab, no-nt, no-winload, no-recov-nor-hid, no-bmgr, notwinboot, nopakmgr, nogrubinstall, no---usr, part-has-no-fstab, not-sep-usr, standard, farbios, /mnt/boot-sav/sda3. sda5 : sda, not-sepboot, no-grubenv nogrub, no-docgrub, no-update-grub, 32, no-boot, no-os, not--efi--part, part-has-no-fstab, part-has-no-fstab, no-nt, no-winload, no-recov-nor-hid, no-bmgr, notwinboot, nopakmgr, nogrubinstall, no---usr, part-has-no-fstab, not-sep-usr, standard, farbios, /mnt/boot-sav/sda5. sda : not-GPT, BIOSboot-not-needed, has-no-EFIpart, not-usb, has-os, 2048 sectors * 512 bytes =================== parted -l: Model: ATA WDC WD7500BPKT-7 (scsi) Disk /dev/sda: 750GB Sector size (logical/physical): 512B/4096B Partition Table: msdos Number Start End Size Type File system Flags 1 106MB 75.2GB 75.1GB primary ntfs boot 2 75.3GB 150GB 75.1GB primary ntfs 3 150GB 170GB 20.1GB primary ntfs 4 170GB 750GB 580GB extended lba 6 170GB 232GB 61.6GB logical ext4 7 232GB 236GB 4181MB logical linux-swap(v1) 5 236GB 750GB 514GB logical ntfs =================== parted -lm: BYT; /dev/sda:750GB:scsi:512:4096:msdos:ATA WDC WD7500BPKT-7; 1:106MB:75.2GB:75.1GB:ntfs::boot; 2:75.3GB:150GB:75.1GB:ntfs::; 3:150GB:170GB:20.1GB:ntfs::; 4:170GB:750GB:580GB:::lba; 6:170GB:232GB:61.6GB:ext4::; 7:232GB:236GB:4181MB:linux-swap(v1)::; 5:236GB:750GB:514GB:ntfs::; =================== mount: /dev/sda6 on / type ext4 (rw,errors=remount-ro) proc on /proc type proc (rw,noexec,nosuid,nodev) sysfs on /sys type sysfs (rw,noexec,nosuid,nodev) none on /sys/fs/fuse/connections type fusectl (rw) none on /sys/kernel/debug type debugfs (rw) none on /sys/kernel/security type securityfs (rw) udev on /dev type devtmpfs (rw,mode=0755) devpts on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=0620) tmpfs on /run type tmpfs (rw,noexec,nosuid,size=10%,mode=0755) none on /run/lock type tmpfs (rw,noexec,nosuid,nodev,size=5242880) none on /run/shm type tmpfs (rw,nosuid,nodev) none on /run/user type tmpfs (rw,noexec,nosuid,nodev,size=104857600,mode=0755) gvfsd-fuse on /run/user/dev/gvfs type fuse.gvfsd-fuse (rw,nosuid,nodev,user=dev) /dev/sda1 on /mnt/boot-sav/sda1 type fuseblk (rw,nosuid,nodev,allow_other,blksize=4096) /dev/sda2 on /mnt/boot-sav/sda2 type fuseblk (rw,nosuid,nodev,allow_other,blksize=4096) /dev/sda3 on /mnt/boot-sav/sda3 type fuseblk (rw,nosuid,nodev,allow_other,blksize=4096) /dev/sda5 on /mnt/boot-sav/sda5 type fuseblk (rw,nosuid,nodev,allow_other,blksize=4096) =================== ls: /sys/block/sda (filtered): alignment_offset bdi capability dev device discard_alignment events events_async events_poll_msecs ext_range holders inflight power queue range removable ro sda1 sda2 sda3 sda4 sda5 sda6 sda7 size slaves stat subsystem trace uevent /sys/block/sr0 (filtered): alignment_offset bdi capability dev device discard_alignment events events_async events_poll_msecs ext_range holders inflight power queue range removable ro size slaves stat subsystem trace uevent /dev (filtered): alarm ashmem autofs binder block bsg btrfs-control bus cdrom cdrw char console core cpu cpu_dma_latency disk dri dvd dvdrw ecryptfs fb0 fb1 fd full fuse hpet input kmsg kvm log mapper mcelog mei mem net network_latency network_throughput null oldmem port ppp psaux ptmx pts random rfkill rtc rtc0 sda sda1 sda2 sda3 sda4 sda5 sda6 sda7 sg0 sg1 shm snapshot snd sr0 stderr stdin stdout uinput urandom v4l vga_arbiter vhost-net video0 zero ls /dev/mapper: control =================== df -Th: Filesystem Type Size Used Avail Use% Mounted on /dev/sda6 ext4 57G 2.7G 51G 6% / udev devtmpfs 1.9G 12K 1.9G 1% /dev tmpfs tmpfs 770M 892K 769M 1% /run none tmpfs 5.0M 0 5.0M 0% /run/lock none tmpfs 1.9G 260K 1.9G 1% /run/shm none tmpfs 100M 44K 100M 1% /run/user /dev/sda1 fuseblk 70G 36G 35G 51% /mnt/boot-sav/sda1 /dev/sda2 fuseblk 70G 66G 4.8G 94% /mnt/boot-sav/sda2 /dev/sda3 fuseblk 19G 87M 19G 1% /mnt/boot-sav/sda3 /dev/sda5 fuseblk 479G 436G 44G 92% /mnt/boot-sav/sda5 =================== fdisk -l: Disk /dev/sda: 750.2 GB, 750156374016 bytes 255 heads, 63 sectors/track, 91201 cylinders, total 1465149168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 4096 bytes / 4096 bytes Disk identifier: 0x1dc69d0b Device Boot Start End Blocks Id System /dev/sda1 * 206848 146802687 73297920 7 HPFS/NTFS/exFAT /dev/sda2 147007488 293623807 73308160 7 HPFS/NTFS/exFAT /dev/sda3 293623808 332820613 19598403 7 HPFS/NTFS/exFAT /dev/sda4 332822526 1465145343 566161409 f W95 Ext'd (LBA) Partition 4 does not start on physical sector boundary. /dev/sda5 461342720 1465145343 501901312 7 HPFS/NTFS/exFAT /dev/sda6 332822528 453171199 60174336 83 Linux /dev/sda7 453173248 461338623 4082688 82 Linux swap / Solaris Partition table entries are not in disk order =================== Recommended repair Recommended-Repair This setting will reinstall the grub2 of sda6 into the MBR of sda. Additional repair will be performed: unhide-bootmenu-10s grub-install (GRUB) 2.00-7ubuntu11,grub-install (GRUB) 2. Reinstall the GRUB of sda6 into the MBR of sda Installation finished. No error reported. grub-install /dev/sda: exit code of grub-install /dev/sda:0 update-grub Generating grub.cfg ... Found linux image: /boot/vmlinuz-3.5.0-17-generic Found initrd image: /boot/initrd.img-3.5.0-17-generic Found memtest86+ image: /boot/memtest86+.bin Found Windows 7 (loader) on /dev/sda1 Unhide GRUB boot menu in sda6/boot/grub/grub.cfg Boot successfully repaired. You can now reboot your computer. The boot files of [The OS now in use - Ubuntu 12.10] are far from the start of the disk. Your BIOS may not detect them. You may want to retry after creating a /boot partition (EXT4, >200MB, start of the disk). This can be performed via tools such as gParted. Then select this partition via the [Separate /boot partition:] option of [Boot Repair]. (https://help.ubuntu.com/community/BootPartition)

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• Making Sense of ASP.NET Paths

  - by Renso

  Making Sense of ASP.NET Paths ASP.Net includes quite a plethora of properties to retrieve path information about the current request, control and application. There's a ton of information available about paths on the Request object, some of it appearing to overlap and some of it buried several levels down, and it can be confusing to find just the right path that you are looking for. To keep things straight I thought it a good idea to summarize the path options along with descriptions and example paths. I wrote a post about this a long time ago in 2004 and I find myself frequently going back to that page to quickly figure out which path I’m looking for in processing the current URL. Apparently a lot of people must be doing the same, because the original post is the second most visited even to this date on this blog to the tune of nearly 500 hits per day. So, I decided to update and expand a bit on the original post with a little more information and clarification based on the original comments. Request Object Paths Available Here's a list of the Path related properties on the Request object (and the Page object). Assume a path like http://www.west-wind.com/webstore/admin/paths.aspx for the paths below where webstore is the name of the virtual. Request Property Description and Value ApplicationPath Returns the web root-relative logical path to the virtual root of this app. /webstore/ PhysicalApplicationPath Returns local file system path of the virtual root for this app. c:\inetpub\wwwroot\webstore PhysicalPath Returns the local file system path to the current script or path. c:\inetpub\wwwroot\webstore\admin\paths.aspx Path FilePath CurrentExecutionFilePath All of these return the full root relative logical path to the script page including path and scriptname. CurrentExcecutionFilePath will return the ‘current’ request path after a Transfer/Execute call while FilePath will always return the original request’s path. /webstore/admin/paths.aspx AppRelativeCurrentExecutionFilePath Returns an ASP.NET root relative virtual path to the script or path for the current request. If in  a Transfer/Execute call the transferred Path is returned. ~/admin/paths.aspx PathInfo Returns any extra path following the script name. If no extra path is provided returns the root-relative path (returns text in red below). string.Empty if no PathInfo is available. /webstore/admin/paths.aspx/ExtraPathInfo RawUrl Returns the full root relative URL including querystring and extra path as a string. /webstore/admin/paths.aspx?sku=wwhelp40 Url Returns a fully qualified URL including querystring and extra path. Note this is a Uri instance rather than string. http://www.west-wind.com/webstore/admin/paths.aspx?sku=wwhelp40 UrlReferrer The fully qualified URL of the page that sent the request. This is also a Uri instance and this value is null if the page was directly accessed by typing into the address bar or using an HttpClient based Referrer client Http header. http://www.west-wind.com/webstore/default.aspx?Info Control.TemplateSourceDirectory Returns the logical path to the folder of the page, master or user control on which it is called. This is useful if you need to know the path only to a Page or control from within the control. For non-file controls this returns the Page path. /webstore/admin/ As you can see there’s a ton of information available there for each of the three common path formats: Physical Path is an OS type path that points to a path or file on disk. Logical Path is a Web path that is relative to the Web server’s root. It includes the virtual plus the application relative path. ~/ (Root-relative) Path is an ASP.NET specific path that includes ~/ to indicate the virtual root Web path. ASP.NET can convert virtual paths into either logical paths using Control.ResolveUrl(), or physical paths using Server.MapPath(). Root relative paths are useful for specifying portable URLs that don’t rely on relative directory structures and very useful from within control or component code. You should be able to get any necessary format from ASP.NET from just about any path or script using these mechanisms. ~/ Root Relative Paths and ResolveUrl() and ResolveClientUrl() ASP.NET supports root-relative virtual path syntax in most of its URL properties in Web Forms. So you can easily specify a root relative path in a control rather than a location relative path: <asp:Image runat="server" ID="imgHelp" ImageUrl="~/images/help.gif" /> ASP.NET internally resolves this URL by using ResolveUrl("~/images/help.gif") to arrive at the root-relative URL of /webstore/images/help.gif which uses the Request.ApplicationPath as the basepath to replace the ~. By convention any custom Web controls also should use ResolveUrl() on URL properties to provide the same functionality. In your own code you can use Page.ResolveUrl() or Control.ResolveUrl() to accomplish the same thing: string imgPath = this.ResolveUrl("~/images/help.gif"); imgHelp.ImageUrl = imgPath; Unfortunately ResolveUrl() is limited to WebForm pages, so if you’re in an HttpHandler or Module it’s not available. ASP.NET Mvc also has it’s own more generic version of ResolveUrl in Url.Decode: <script src="<%= Url.Content("~/scripts/new.js") %>" type="text/javascript"></script> which is part of the UrlHelper class. In ASP.NET MVC the above sort of syntax is actually even more crucial than in WebForms due to the fact that views are not referencing specific pages but rather are often path based which can lead to various variations on how a particular view is referenced. In a Module or Handler code Control.ResolveUrl() unfortunately is not available which in retrospect seems like an odd design choice – URL resolution really should happen on a Request basis not as part of the Page framework. Luckily you can also rely on the static VirtualPathUtility class: string path = VirtualPathUtility.ToAbsolute("~/admin/paths.aspx"); VirtualPathUtility also many other quite useful methods for dealing with paths and converting between the various kinds of paths supported. One thing to watch out for is that ToAbsolute() will throw an exception if a query string is provided and doesn’t work on fully qualified URLs. I wrote about this topic with a custom solution that works fully qualified URLs and query strings here (check comments for some interesting discussions too). Similar to ResolveUrl() is ResolveClientUrl() which creates a fully qualified HTTP path that includes the protocol and domain name. It’s rare that this full resolution is needed but can be useful in some scenarios. Mapping Virtual Paths to Physical Paths with Server.MapPath() If you need to map root relative or current folder relative URLs to physical URLs or you can use HttpContext.Current.Server.MapPath(). Inside of a Page you can do the following: string physicalPath = Server.MapPath("~/scripts/ww.jquery.js")); MapPath is pretty flexible and it understands both ASP.NET style virtual paths as well as plain relative paths, so the following also works. string physicalPath = Server.MapPath("scripts/silverlight.js"); as well as dot relative syntax: string physicalPath = Server.MapPath("../scripts/jquery.js"); Once you have the physical path you can perform standard System.IO Path and File operations on the file. Remember with physical paths and IO or copy operations you need to make sure you have permissions to access files and folders based on the Web server user account that is active (NETWORK SERVICE, ASPNET typically). Note the Server.MapPath will not map up beyond the virtual root of the application for security reasons. Server and Host Information Between these settings you can get all the information you may need to figure out where you are at and to build new Url if necessary. If you need to build a URL completely from scratch you can get access to information about the server you are accessing: Server Variable Function and Example SERVER_NAME The of the domain or IP Address wwww.west-wind.com or 127.0.0.1 SERVER_PORT The port that the request runs under. 80 SERVER_PORT_SECURE Determines whether https: was used. 0 or 1 APPL_MD_PATH ADSI DirectoryServices path to the virtual root directory. Note that LM typically doesn’t work for ADSI access so you should replace that with LOCALHOST or the machine’s NetBios name. /LM/W3SVC/1/ROOT/webstore Request.Url and Uri Parsing If you still need more control over the current request URL or  you need to create new URLs from an existing one, the current Request.Url Uri property offers a lot of control. Using the Uri class and UriBuilder makes it easy to retrieve parts of a URL and create new URLs based on existing URL. The UriBuilder class is the preferred way to create URLs – much preferable over creating URIs via string concatenation. Uri Property Function Scheme The URL scheme or protocol prefix. http or https Port The port if specifically specified. DnsSafeHost The domain name or local host NetBios machine name www.west-wind.com or rasnote LocalPath The full path of the URL including script name and extra PathInfo. /webstore/admin/paths.aspx Query The query string if any ?id=1 The Uri class itself is great for retrieving Uri parts, but most of the properties are read only if you need to modify a URL in order to change it you can use the UriBuilder class to load up an existing URL and modify it to create a new one. Here are a few common operations I’ve needed to do to get specific URLs: Convert the Request URL to an SSL/HTTPS link For example to take the current request URL and converted  it to a secure URL can be done like this: UriBuilder build = new UriBuilder(Request.Url); build.Scheme = "https"; build.Port = -1; // don't inject portUri newUri = build.Uri; string newUrl = build.ToString(); Retrieve the fully qualified URL without a QueryString AFAIK, there’s no native routine to retrieve the current request URL without the query string. It’s easy to do with UriBuilder however: UriBuilder builder = newUriBuilder(Request.Url); builder.Query = ""; stringlogicalPathWithoutQuery = builder.ToString();

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• Hello Operator, My Switch Is Bored

  - by Paul White

  This is a post for T-SQL Tuesday #43 hosted by my good friend Rob Farley. The topic this month is Plan Operators. I haven’t taken part in T-SQL Tuesday before, but I do like to write about execution plans, so this seemed like a good time to start. This post is in two parts. The first part is primarily an excuse to use a pretty bad play on words in the title of this blog post (if you’re too young to know what a telephone operator or a switchboard is, I hate you). The second part of the post looks at an invisible query plan operator (so to speak). 1. My Switch Is Bored Allow me to present the rare and interesting execution plan operator, Switch: Books Online has this to say about Switch: Following that description, I had a go at producing a Fast Forward Cursor plan that used the TOP operator, but had no luck. That may be due to my lack of skill with cursors, I’m not too sure. The only application of Switch in SQL Server 2012 that I am familiar with requires a local partitioned view: CREATE TABLE dbo.T1 (c1 int NOT NULL CHECK (c1 BETWEEN 00 AND 24)); CREATE TABLE dbo.T2 (c1 int NOT NULL CHECK (c1 BETWEEN 25 AND 49)); CREATE TABLE dbo.T3 (c1 int NOT NULL CHECK (c1 BETWEEN 50 AND 74)); CREATE TABLE dbo.T4 (c1 int NOT NULL CHECK (c1 BETWEEN 75 AND 99)); GO CREATE VIEW V1 AS SELECT c1 FROM dbo.T1 UNION ALL SELECT c1 FROM dbo.T2 UNION ALL SELECT c1 FROM dbo.T3 UNION ALL SELECT c1 FROM dbo.T4; Not only that, but it needs an updatable local partitioned view. We’ll need some primary keys to meet that requirement: ALTER TABLE dbo.T1 ADD CONSTRAINT PK_T1 PRIMARY KEY (c1);   ALTER TABLE dbo.T2 ADD CONSTRAINT PK_T2 PRIMARY KEY (c1);   ALTER TABLE dbo.T3 ADD CONSTRAINT PK_T3 PRIMARY KEY (c1);   ALTER TABLE dbo.T4 ADD CONSTRAINT PK_T4 PRIMARY KEY (c1); We also need an INSERT statement that references the view. Even more specifically, to see a Switch operator, we need to perform a single-row insert (multi-row inserts use a different plan shape): INSERT dbo.V1 (c1) VALUES (1); And now…the execution plan: The Constant Scan manufactures a single row with no columns. The Compute Scalar works out which partition of the view the new value should go in. The Assert checks that the computed partition number is not null (if it is, an error is returned). The Nested Loops Join executes exactly once, with the partition id as an outer reference (correlated parameter). The Switch operator checks the value of the parameter and executes the corresponding input only. If the partition id is 0, the uppermost Clustered Index Insert is executed, adding a row to table T1. If the partition id is 1, the next lower Clustered Index Insert is executed, adding a row to table T2…and so on. In case you were wondering, here’s a query and execution plan for a multi-row insert to the view: INSERT dbo.V1 (c1) VALUES (1), (2); Yuck! An Eager Table Spool and four Filters! I prefer the Switch plan. My guess is that almost all the old strategies that used a Switch operator have been replaced over time, using things like a regular Concatenation Union All combined with Start-Up Filters on its inputs. Other new (relative to the Switch operator) features like table partitioning have specific execution plan support that doesn’t need the Switch operator either. This feels like a bit of a shame, but perhaps it is just nostalgia on my part, it’s hard to know. Please do let me know if you encounter a query that can still use the Switch operator in 2012 – it must be very bored if this is the only possible modern usage! 2. Invisible Plan Operators The second part of this post uses an example based on a question Dave Ballantyne asked using the SQL Sentry Plan Explorer plan upload facility. If you haven’t tried that yet, make sure you’re on the latest version of the (free) Plan Explorer software, and then click the Post to SQLPerformance.com button. That will create a site question with the query plan attached (which can be anonymized if the plan contains sensitive information). Aaron Bertrand and I keep a close eye on questions there, so if you have ever wanted to ask a query plan question of either of us, that’s a good way to do it. The problem The issue I want to talk about revolves around a query issued against a calendar table. The script below creates a simplified version and adds 100 years of per-day information to it: USE tempdb; GO CREATE TABLE dbo.Calendar ( dt date NOT NULL, isWeekday bit NOT NULL, theYear smallint NOT NULL,   CONSTRAINT PK__dbo_Calendar_dt PRIMARY KEY CLUSTERED (dt) ); GO -- Monday is the first day of the week for me SET DATEFIRST 1;   -- Add 100 years of data INSERT dbo.Calendar WITH (TABLOCKX) (dt, isWeekday, theYear) SELECT CA.dt, isWeekday = CASE WHEN DATEPART(WEEKDAY, CA.dt) IN (6, 7) THEN 0 ELSE 1 END, theYear = YEAR(CA.dt) FROM Sandpit.dbo.Numbers AS N CROSS APPLY ( VALUES (DATEADD(DAY, N.n - 1, CONVERT(date, '01 Jan 2000', 113))) ) AS CA (dt) WHERE N.n BETWEEN 1 AND 36525; The following query counts the number of weekend days in 2013: SELECT Days = COUNT_BIG(*) FROM dbo.Calendar AS C WHERE theYear = 2013 AND isWeekday = 0; It returns the correct result (104) using the following execution plan: The query optimizer has managed to estimate the number of rows returned from the table exactly, based purely on the default statistics created separately on the two columns referenced in the query’s WHERE clause. (Well, almost exactly, the unrounded estimate is 104.289 rows.) There is already an invisible operator in this query plan – a Filter operator used to apply the WHERE clause predicates. We can see it by re-running the query with the enormously useful (but undocumented) trace flag 9130 enabled: Now we can see the full picture. The whole table is scanned, returning all 36,525 rows, before the Filter narrows that down to just the 104 we want. Without the trace flag, the Filter is incorporated in the Clustered Index Scan as a residual predicate. It is a little bit more efficient than using a separate operator, but residual predicates are still something you will want to avoid where possible. The estimates are still spot on though: Anyway, looking to improve the performance of this query, Dave added the following filtered index to the Calendar table: CREATE NONCLUSTERED INDEX Weekends ON dbo.Calendar(theYear) WHERE isWeekday = 0; The original query now produces a much more efficient plan: Unfortunately, the estimated number of rows produced by the seek is now wrong (365 instead of 104): What’s going on? The estimate was spot on before we added the index! Explanation You might want to grab a coffee for this bit. Using another trace flag or two (8606 and 8612) we can see that the cardinality estimates were exactly right initially: The highlighted information shows the initial cardinality estimates for the base table (36,525 rows), the result of applying the two relational selects in our WHERE clause (104 rows), and after performing the COUNT_BIG(*) group by aggregate (1 row). All of these are correct, but that was before cost-based optimization got involved :) Cost-based optimization When cost-based optimization starts up, the logical tree above is copied into a structure (the ‘memo’) that has one group per logical operation (roughly speaking). The logical read of the base table (LogOp_Get) ends up in group 7; the two predicates (LogOp_Select) end up in group 8 (with the details of the selections in subgroups 0-6). These two groups still have the correct cardinalities as trace flag 8608 output (initial memo contents) shows: During cost-based optimization, a rule called SelToIdxStrategy runs on group 8. It’s job is to match logical selections to indexable expressions (SARGs). It successfully matches the selections (theYear = 2013, is Weekday = 0) to the filtered index, and writes a new alternative into the memo structure. The new alternative is entered into group 8 as option 1 (option 0 was the original LogOp_Select): The new alternative is to do nothing (PhyOp_NOP = no operation), but to instead follow the new logical instructions listed below the NOP. The LogOp_GetIdx (full read of an index) goes into group 21, and the LogOp_SelectIdx (selection on an index) is placed in group 22, operating on the result of group 21. The definition of the comparison ‘the Year = 2013’ (ScaOp_Comp downwards) was already present in the memo starting at group 2, so no new memo groups are created for that. New Cardinality Estimates The new memo groups require two new cardinality estimates to be derived. First, LogOp_Idx (full read of the index) gets a predicted cardinality of 10,436. This number comes from the filtered index statistics: DBCC SHOW_STATISTICS (Calendar, Weekends) WITH STAT_HEADER; The second new cardinality derivation is for the LogOp_SelectIdx applying the predicate (theYear = 2013). To get a number for this, the cardinality estimator uses statistics for the column ‘theYear’, producing an estimate of 365 rows (there are 365 days in 2013!): DBCC SHOW_STATISTICS (Calendar, theYear) WITH HISTOGRAM; This is where the mistake happens. Cardinality estimation should have used the filtered index statistics here, to get an estimate of 104 rows: DBCC SHOW_STATISTICS (Calendar, Weekends) WITH HISTOGRAM; Unfortunately, the logic has lost sight of the link between the read of the filtered index (LogOp_GetIdx) in group 22, and the selection on that index (LogOp_SelectIdx) that it is deriving a cardinality estimate for, in group 21. The correct cardinality estimate (104 rows) is still present in the memo, attached to group 8, but that group now has a PhyOp_NOP implementation. Skipping over the rest of cost-based optimization (in a belated attempt at brevity) we can see the optimizer’s final output using trace flag 8607: This output shows the (incorrect, but understandable) 365 row estimate for the index range operation, and the correct 104 estimate still attached to its PhyOp_NOP. This tree still has to go through a few post-optimizer rewrites and ‘copy out’ from the memo structure into a tree suitable for the execution engine. One step in this process removes PhyOp_NOP, discarding its 104-row cardinality estimate as it does so. To finish this section on a more positive note, consider what happens if we add an OVER clause to the query aggregate. This isn’t intended to be a ‘fix’ of any sort, I just want to show you that the 104 estimate can survive and be used if later cardinality estimation needs it: SELECT Days = COUNT_BIG(*) OVER () FROM dbo.Calendar AS C WHERE theYear = 2013 AND isWeekday = 0; The estimated execution plan is: Note the 365 estimate at the Index Seek, but the 104 lives again at the Segment! We can imagine the lost predicate ‘isWeekday = 0’ as sitting between the seek and the segment in an invisible Filter operator that drops the estimate from 365 to 104. Even though the NOP group is removed after optimization (so we don’t see it in the execution plan) bear in mind that all cost-based choices were made with the 104-row memo group present, so although things look a bit odd, it shouldn’t affect the optimizer’s plan selection. I should also mention that we can work around the estimation issue by including the index’s filtering columns in the index key: CREATE NONCLUSTERED INDEX Weekends ON dbo.Calendar(theYear, isWeekday) WHERE isWeekday = 0 WITH (DROP_EXISTING = ON); There are some downsides to doing this, including that changes to the isWeekday column may now require Halloween Protection, but that is unlikely to be a big problem for a static calendar table ;)  With the updated index in place, the original query produces an execution plan with the correct cardinality estimation showing at the Index Seek: That’s all for today, remember to let me know about any Switch plans you come across on a modern instance of SQL Server! Finally, here are some other posts of mine that cover other plan operators: Segment and Sequence Project Common Subexpression Spools Why Plan Operators Run Backwards Row Goals and the Top Operator Hash Match Flow Distinct Top N Sort Index Spools and Page Splits Singleton and Range Seeks Bitmaps Hash Join Performance Compute Scalar © 2013 Paul White – All Rights Reserved Twitter: @SQL_Kiwi

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• Oracle VM Deep Dives

  - by rickramsey

  "With IT staff now tasked to deliver on-demand services, datacenter virtualization requirements have gone beyond simple consolidation and cost reduction. Simply provisioning and delivering an operating environment falls short. IT organizations must rapidly deliver services, such as infrastructure-as-a-service (IaaS), platform-as-a-service (PaaS), and software-as-a-service (SaaS). Virtualization solutions need to be application-driven and enable:" "Easier deployment and management of business critical applications" "Rapid and automated provisioning of the entire application stack inside the virtual machine" "Integrated management of the complete stack including the VM and the applications running inside the VM." Application Driven Virtualization, an Oracle white paper That was published in August of 2011. The new release of Oracle VM Server delivers significant virtual networking performance improvements, among other things. If you're not sure how virtual networks work or how to use them, these two articles by Greg King and friends might help. Looking Under the Hood at Virtual Networking by Greg King Oracle VM Server for x86 lets you create logical networks out of physical Ethernet ports, bonded ports, VLAN segments, virtual MAC addresses (VNICs), and network channels. You can then assign channels (or "roles") to each logical network so that it handles the type of traffic you want it to. Greg King explains how you go about doing this, and how Oracle VM Server for x86 implements the network infrastructure you configured. He also describes how the VM interacts with paravirtualized guest operating systems, hardware virtualized operating systems, and VLANs. Finally, he provides an example that shows you how it all looks from the VM Manager view, the logical view, and the command line view of Oracle VM Server for x86. Fundamental Concepts of VLAN Networks by Greg King and Don Smerker Oracle VM Server for x86 supports a wide range of options in network design, varying in complexity from a single network to configurations that include network bonds, VLANS, bridges, and multiple networks connecting the Oracle VM servers and guests. You can create separate networks to isolate traffic, or you can configure a single network for multiple roles. Network design depends on many factors, including the number and type of network interfaces, reliability and performance goals, the number of Oracle VM servers and guests, and the anticipated workload. The Oracle VM Manager GUI presents four different ways to create an Oracle VM network: Bonds and ports VLANs Both bond/ports and VLANS A local network This article focuses the second option, designing a complex Oracle VM network infrastructure using only VLANs, and it steps through the concepts needed to create a robust network infrastructure for your Oracle VM servers and guests. More Resources Virtual Networking for Dummies Download Oracle VM Server for x86 Find technical resources for Oracle VM Server for x86 -Rick Follow me on: Blog | Facebook | Twitter | Personal Twitter | YouTube | The Great Peruvian Novel

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