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  • How can I prevent ubuntu from mounting particular partitions/deivices?

    - by Patryk
    I would like to stop Ubuntu from mounting my other (Windows') partitions automatically (since I do not need it really often - and especially I would like not to automount "System reserved" partition for Windows. There is a similar question here How can I stop Ubuntu 12.04 from mounting Fedora 16's Swap Partition? but! I do not have these partitions added in /etc/fstab. How can I do it ? For proof, my /etc/fstab proc /proc proc nodev,noexec,nosuid 0 0 # / was on /dev/sda7 during installation UUID=1384cee0-6a71-4b83-b0d3-1338db925168 / ext4 errors=remount-ro 0 1 # swap was on /dev/sda6 during installation UUID=e3729117-b936-4c1d-9883-aee73dab6729 none swap sw 0 0 #------ MY WINDOWS D DRIVE---------- I WANT TO KEP IT UUID=98E8B14DE8B12A80 /media/d ntfs defaults,errors=remount-ro 0 0

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  • SSD Tweaks for Ubuntu 12.04

    - by Mustafa Erdinç
    I need to tweak my Dell XPS 13z SSD for maximum performance and life cycle than I read the solutions explained here, but it is for 11.10 and my fstab is different. For now my fstab is looks like this: proc /proc proc nodev,noexec,nosuid 0 0 # / was on /dev/sda1 during installation UUID=abf5ce9e-bdb7-4b2f-a7bd-bbd9efa72a98 / ext4 errors=remount-ro 0 1 # /home was on /dev/sda2 during installation UUID=491427b2-7482-4483-b6eb-7c564b991aff /home ext4 defaults 0 2 # swap was on /dev/sda3 during installation #UUID=7551000d-e708-4e0f-9fd2-9f93119f63fb none swap sw 0 0 /dev/mapper/cryptswap1 none swap sw 0 0 tmpfs /tmp tmpfs mode=1777 And my rc.local is looks like this: echo noop > /sys/block/sda/queue/scheduler echo deadline > /sys/block/sda/queue/scheduler echo 1 > /sys/block/sda/queue/iosched/fifo_batch exit 0 Do you have any suggestions, what should I do? Regards

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  • Ubuntu missing from the Grub menu

    - by varevarao
    Recently I've had some audio issues with Ubuntu (using precise), and in the process of trying to resolve that I ran a dist-upgrade. Everything went just fine, and the sound seemed good, until I rebooted my machine for the first time since the dist-upgrade. All I see now in the Grub menu at startup is memtest86+, another memtest variant, and Windows 7. It's not showing any of the linux kernels that Ubuntu is running on. I am attaching my bootinfoscript: Boot Info Script 0.61.full + Boot-Repair extra info [Boot-Info November 20th 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 (,msdos6)/boot/grub on this drive. sda1: __________________________________________________________________________ File system: vfat Boot sector type: Dell Utility: FAT16 Boot sector info: No errors found in the Boot Parameter Block. Operating System: Boot files: 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: Windows 7 Boot files: sda4: __________________________________________________________________________ File system: Extended Partition Boot sector type: Unknown 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: Grub2 (v1.99-2.00) Boot sector info: Grub2 (v1.99) is installed in the boot sector of sda6 and looks at sector 220046240 of the same hard drive for core.img. core.img is at this location and looks for (,msdos6)/boot/grub on this drive. Operating System: Ubuntu 12.04.1 LTS Boot files: /boot/grub/grub.cfg /etc/fstab /boot/grub/core.img sda7: __________________________________________________________________________ File system: swap Boot sector type: - Boot sector info: ============================ Drive/Partition Info: ============================= Drive: sda _____________________________________________________________________ Disk /dev/sda: 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/sda1 63 273,104 273,042 de Dell Utility /dev/sda2 * 274,432 19,406,847 19,132,416 7 NTFS / exFAT / HPFS /dev/sda3 19,406,848 218,274,364 198,867,517 7 NTFS / exFAT / HPFS /dev/sda4 218,275,838 625,139,711 406,863,874 f W95 Extended (LBA) /dev/sda5 328,630,272 625,139,711 296,509,440 7 NTFS / exFAT / HPFS /dev/sda6 218,275,840 324,030,463 105,754,624 83 Linux /dev/sda7 324,032,512 328,626,175 4,593,664 82 Linux swap / Solaris "blkid" output: ________________________________________________________________ Device UUID TYPE LABEL /dev/loop0 squashfs /dev/sda1 07DA-0512 vfat DellUtility /dev/sda2 8834146034145392 ntfs RECOVERY /dev/sda3 48E2189DE21890F4 ntfs OS /dev/sda5 BC2A44C02A447982 ntfs Varshneya /dev/sda6 34731459-4b0f-46ac-a9bf-cb360a2c947c ext4 /dev/sda7 dcb9ce9b-799a-4c65-b008-887b01775670 swap /dev/sr0 iso9660 Ubuntu 12.04.1 LTS i386 ================================ Mount points: ================================= Device Mount_Point Type Options /dev/loop0 /rofs squashfs (ro,noatime) /dev/sda6 /mnt ext4 (rw) /dev/sr0 /cdrom iso9660 (ro,noatime) =========================== 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 $prefix/grubenv ]; then set have_grubenv=true load_env fi set default="0" if [ "${prev_saved_entry}" ]; then set saved_entry="${prev_saved_entry}" save_env saved_entry set prev_saved_entry= save_env prev_saved_entry set boot_once=true fi function savedefault { if [ -z "${boot_once}" ]; then saved_entry="${chosen}" save_env saved_entry fi } function recordfail { set recordfail=1 if [ -n "${have_grubenv}" ]; then if [ -z "${boot_once}" ]; then save_env recordfail; fi; fi } function load_video { insmod vbe insmod vga insmod video_bochs insmod video_cirrus } insmod part_msdos insmod ext2 set root='(hd0,msdos6)' search --no-floppy --fs-uuid --set=root 34731459-4b0f-46ac-a9bf-cb360a2c947c if loadfont /boot/grub/unicode.pf2 ; then set gfxmode=auto load_video insmod gfxterm insmod part_msdos insmod ext2 set root='(hd0,msdos6)' search --no-floppy --fs-uuid --set=root 34731459-4b0f-46ac-a9bf-cb360a2c947c set locale_dir=($root)/boot/grub/locale set lang=en_US insmod gettext fi terminal_output gfxterm if [ "${recordfail}" = 1 ]; then set timeout=-1 else set timeout=10 fi ### END /etc/grub.d/00_header ### ### BEGIN /etc/grub.d/05_debian_theme ### set menu_color_normal=white/black set menu_color_highlight=black/light-gray ### END /etc/grub.d/05_debian_theme ### ### BEGIN /etc/grub.d/10_linux ### function gfxmode { set gfxpayload="${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 ### END /etc/grub.d/10_linux ### ### BEGIN /etc/grub.d/20_linux_xen ### ### END /etc/grub.d/20_linux_xen ### ### BEGIN /etc/grub.d/20_memtest86+ ### menuentry "Memory test (memtest86+)" { insmod part_msdos insmod ext2 set root='(hd0,msdos6)' search --no-floppy --fs-uuid --set=root 34731459-4b0f-46ac-a9bf-cb360a2c947c linux16 /boot/memtest86+.bin } menuentry "Memory test (memtest86+, serial console 115200)" { insmod part_msdos insmod ext2 set root='(hd0,msdos6)' search --no-floppy --fs-uuid --set=root 34731459-4b0f-46ac-a9bf-cb360a2c947c 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/sda2)" --class windows --class os { insmod part_msdos insmod ntfs set root='(hd0,msdos2)' search --no-floppy --fs-uuid --set=root 8834146034145392 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 ### -------------------------------------------------------------------------------- =============================== sda6/etc/fstab: ================================ -------------------------------------------------------------------------------- # /etc/fstab: static file system information. # # Use 'blkid -o value -s UUID' 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/sda6 during installation UUID=34731459-4b0f-46ac-a9bf-cb360a2c947c / ext4 errors=remount-ro,user_xattr 0 1 # swap was on /dev/sda7 during installation UUID=dcb9ce9b-799a-4c65-b008-887b01775670 none swap sw 0 0 -------------------------------------------------------------------------------- =================== sda6: Location of files loaded by Grub: ==================== GiB - GB File Fragment(s) 104.851909637 = 112.583880704 boot/grub/core.img 1 121.191410065 = 130.128285696 boot/grub/grub.cfg 1 ======================== Unknown MBRs/Boot Sectors/etc: ======================== Unknown BootLoader on sda4 00000000 eb 0f 2a 5d f4 b7 75 f2 e9 56 12 b8 50 b4 79 ec |..*]..u..V..P.y.| 00000010 89 91 ca c3 16 40 31 d0 ae c4 53 3d c7 dd d7 98 |[email protected]=....| 00000020 bd a4 f2 a4 e8 ab fc ea 36 30 1b 34 cf 8a 28 30 |........60.4..(0| 00000030 43 95 6c 31 3e 76 93 58 84 37 99 c3 ae 3a 88 a3 |C.l1>v.X.7...:..| 00000040 c2 a6 36 2a f8 e0 e1 03 91 8d a1 50 cd ad b0 b5 |..6*.......P....| 00000050 ad 69 3a 49 63 1f 4a 33 97 6e 0c 71 bf 7d bd 35 |.i:Ic.J3.n.q.}.5| 00000060 86 c5 17 93 b4 9f e5 af e0 c4 6f f4 6f f9 4b dd |..........o.o.K.| 00000070 14 39 e2 9e b9 36 ca b1 56 5b d9 b1 66 2c 05 b2 |.9...6..V[..f,..| 00000080 5d 5b 99 c0 db e6 81 27 ab c2 e1 55 00 ac 0b 2c |][.....'...U...,| 00000090 24 d3 8e 54 b0 3d ab 58 e4 23 fc 3a 79 93 fb 5e |$..T.=.X.#.:y..^| 000000a0 94 5a 3a c2 16 4e 56 cb 1b 7f 7e b3 4c 38 ca 5b |.Z:..NV...~.L8.[| 000000b0 ca ab c1 2c 2a 64 e7 77 fe 2a ba ee 08 33 b5 9b |...,*d.w.*...3..| 000000c0 d0 c2 b4 a8 fc 73 4f 01 fd 03 61 75 eb 6d 1a 74 |.....sO...au.m.t| 000000d0 5f 79 31 7f ed e6 f5 99 21 36 16 ed 25 d9 6d 2b |_y1.....!6..%.m+| 000000e0 5f f4 42 b8 9d 01 89 10 fe df a4 98 e7 ab ab ea |_.B.............| 000000f0 1d 1c 44 e1 49 d9 19 c9 ab f5 41 eb 4a 32 c2 39 |..D.I.....A.J2.9| 00000100 87 57 f6 f6 f3 b5 4d 17 72 f2 b1 16 19 aa ec 24 |.W....M.r......$| 00000110 39 bd e3 b1 68 b3 b0 7f fa 2a 3a 2e 99 ed db 8a |9...h....*:.....| 00000120 f8 61 b4 ef 9d 7d 85 95 ed ad eb 9e 71 f4 27 d3 |.a...}......q.'.| 00000130 f3 04 8b 8a 69 98 02 72 df e1 f9 83 27 5b 01 4c |....i..r....'[.L| 00000140 d4 9a b9 3b db ca 1e 40 35 db 6f c1 52 c0 7f 27 |...;[email protected]..'| 00000150 8a 1d bc 34 89 24 b6 e3 fd ec a1 2a e5 9e d1 8f |...4.$.....*....| 00000160 77 e0 d5 52 c0 4c c4 38 38 3c 28 19 bf 20 f0 03 |w..R.L.88<(.. ..| 00000170 38 a4 b1 b5 ed 6a b8 f7 a9 7b 65 b1 7b 64 4a 33 |8....j...{e.{dJ3| 00000180 66 1a 60 29 38 1d 5b 52 40 31 de a5 0c 0f cc 6f |f.`)8.[[email protected]| 00000190 dd 31 6d 3d f0 2a 32 85 67 66 ca 4f 02 aa 0d 30 |.1m=.*2.gf.O...0| 000001a0 66 c9 b2 33 c2 4b 8a fa 3c 7b 52 02 00 88 8e cf |f..3.K..<{R.....| 000001b0 67 1e d4 20 49 1d 1a b8 71 ad c2 d4 37 9d 00 fe |g.. I...q...7...| 000001c0 ff ff 07 fe ff ff 02 e0 93 06 00 60 ac 11 00 fe |...........`....| 000001d0 ff ff 05 fe ff ff 01 00 00 00 01 b0 4d 06 00 00 |............M...| 000001e0 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 ADDITIONAL INFORMATION : =================== log of boot-repair 2012-11-24__09h45 =================== boot-repair version : 3.195~ppa2~precise boot-sav version : 3.195~ppa2~precise glade2script version : 3.2.2~ppa45~precise boot-sav-extra version : 3.195~ppa2~precise boot-repair is executed in live-session (Ubuntu 12.04.1 LTS, precise, Ubuntu, i686) CPU op-mode(s): 32-bit, 64-bit file=/cdrom/preseed/ubuntu.seed boot=casper initrd=/casper/initrd.lz quiet splash -- =================== os-prober: /dev/sda2:Windows 7 (loader):Windows:chain /dev/sda6:Ubuntu 12.04.1 LTS (12.04):Ubuntu:linux =================== blkid: /dev/sda1: SEC_TYPE="msdos" LABEL="DellUtility" UUID="07DA-0512" TYPE="vfat" /dev/sda2: LABEL="RECOVERY" UUID="8834146034145392" TYPE="ntfs" /dev/sda3: LABEL="OS" UUID="48E2189DE21890F4" TYPE="ntfs" /dev/sda5: LABEL="Varshneya" UUID="BC2A44C02A447982" TYPE="ntfs" /dev/loop0: TYPE="squashfs" /dev/sda6: UUID="34731459-4b0f-46ac-a9bf-cb360a2c947c" TYPE="ext4" /dev/sda7: UUID="dcb9ce9b-799a-4c65-b008-887b01775670" TYPE="swap" /dev/sr0: LABEL="Ubuntu 12.04.1 LTS i386" TYPE="iso9660" 1 disks with OS, 2 OS : 1 Linux, 0 MacOS, 1 Windows, 0 unknown type OS. Windows not detected by os-prober on sda3. Warning: extended partition does not start at a cylinder boundary. DOS and Linux will interpret the contents differently. =================== /mnt/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" =================== /mnt/etc/grub.d/ : drwxr-xr-x 2 root root 4096 Nov 22 16:15 grub.d total 56 -rwxr-xr-x 1 root root 6743 Sep 12 20:19 00_header -rwxr-xr-x 1 root root 5522 Sep 12 20:05 05_debian_theme -rwxr-xr-x 1 root root 7407 Sep 12 20:19 10_linux -rwxr-xr-x 1 root root 6335 Sep 12 20:19 20_linux_xen -rwxr-xr-x 1 root root 1588 Sep 24 2010 20_memtest86+ -rwxr-xr-x 1 root root 7603 Sep 12 20:19 30_os-prober -rwxr-xr-x 1 root root 214 Sep 12 20:19 40_custom -rwxr-xr-x 1 root root 95 Sep 12 20:19 41_custom -rw-r--r-- 1 root root 483 Sep 12 20:19 README =================== No kernel in /mnt/boot: grub memtest86+.bin memtest86+_multiboot.bin =================== UEFI/Legacy mode: This live-session is not EFI-compatible. SecureBoot maybe enabled. =================== PARTITIONS & DISKS: sda1 : 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, not-far, /mnt/boot-sav/sda1. sda2 : 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, no-winload, no-recov-nor-hid, bootmgr, is-winboot, nopakmgr, nogrubinstall, no---usr, part-has-no-fstab, not-sep-usr, standard, not-far, /mnt/boot-sav/sda2. sda3 : 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, 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. sda6 : sda, not-sepboot, grubenv-ok grub2, grub-pc, update-grub, 64, no-kernel, 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, /mnt. sda : not-GPT, BIOSboot-not-needed, has-no-EFIpart, not-usb, has-os, 63 sectors * 512 bytes =================== parted -l: Model: ATA ST9320423AS (scsi) Disk /dev/sda: 320GB Sector size (logical/physical): 512B/512B Partition Table: msdos Number Start End Size Type File system Flags 1 32.3kB 140MB 140MB primary fat16 diag 2 141MB 9936MB 9796MB primary ntfs boot 3 9936MB 112GB 102GB primary ntfs 4 112GB 320GB 208GB extended lba 6 112GB 166GB 54.1GB logical ext4 7 166GB 168GB 2352MB logical linux-swap(v1) 5 168GB 320GB 152GB logical ntfs Model: HL-DT-ST DVD+-RW GA31N (scsi) Disk /dev/sr0: 4700MB Sector size (logical/physical): 2048B/2048B Partition Table: msdos Number Start End Size Type File system Flags 1 131kB 2916MB 2916MB primary boot, hidden =================== parted -lm: BYT; /dev/sda:320GB:scsi:512:512:msdos:ATA ST9320423AS; 1:32.3kB:140MB:140MB:fat16::diag; 2:141MB:9936MB:9796MB:ntfs::boot; 3:9936MB:112GB:102GB:ntfs::; 4:112GB:320GB:208GB:::lba; 6:112GB:166GB:54.1GB:ext4::; 7:166GB:168GB:2352MB:linux-swap(v1)::; 5:168GB:320GB:152GB:ntfs::; BYT; /dev/sr0:4700MB:scsi:2048:2048:msdos:HL-DT-ST DVD+-RW GA31N; 1:131kB:2916MB:2916MB:::boot, hidden; =================== mount: /cow on / type overlayfs (rw) proc on /proc type proc (rw,noexec,nosuid,nodev) sysfs on /sys type sysfs (rw,noexec,nosuid,nodev) 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) /dev/sr0 on /cdrom type iso9660 (ro,noatime) /dev/loop0 on /rofs type squashfs (ro,noatime) 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) tmpfs on /tmp type tmpfs (rw,nosuid,nodev) none on /run/lock type tmpfs (rw,noexec,nosuid,nodev,size=5242880) none on /run/shm type tmpfs (rw,nosuid,nodev) gvfs-fuse-daemon on /home/ubuntu/.gvfs type fuse.gvfs-fuse-daemon (rw,nosuid,nodev,user=ubuntu) /dev/sda6 on /mnt type ext4 (rw) /dev on /mnt/dev type none (rw,bind) /proc on /mnt/proc type none (rw,bind) /sys on /mnt/sys type none (rw,bind) /usr on /mnt/usr type none (rw,bind) /dev/sda1 on /mnt/boot-sav/sda1 type vfat (rw) /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): autofs block bsg btrfs-control bus cdrom cdrw char console core cpu cpu_dma_latency disk dri dvd dvdrw ecryptfs fb0 fd full fuse fw0 hidraw0 hpet input kmsg 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 usbmon0 usbmon1 usbmon2 v4l vga_arbiter video0 zero ls /dev/mapper: control =================== df -Th: Filesystem Type Size Used Avail Use% Mounted on /cow overlayfs 1.9G 113M 1.8G 6% / udev devtmpfs 1.9G 12K 1.9G 1% /dev tmpfs tmpfs 777M 872K 776M 1% /run /dev/sr0 iso9660 696M 696M 0 100% /cdrom /dev/loop0 squashfs 667M 667M 0 100% /rofs tmpfs tmpfs 1.9G 20K 1.9G 1% /tmp none tmpfs 5.0M 0 5.0M 0% /run/lock none tmpfs 1.9G 176K 1.9G 1% /run/shm /dev/sda6 ext4 51G 27G 22G 56% /mnt /dev/sda1 vfat 134M 9.1M 125M 7% /mnt/boot-sav/sda1 /dev/sda2 fuseblk 9.2G 5.6G 3.6G 61% /mnt/boot-sav/sda2 /dev/sda3 fuseblk 95G 80G 16G 84% /mnt/boot-sav/sda3 /dev/sda5 fuseblk 142G 130G 12G 92% /mnt/boot-sav/sda5 =================== fdisk -l: Disk /dev/sda: 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: 0xb8000000 Device Boot Start End Blocks Id System /dev/sda1 63 273104 136521 de Dell Utility /dev/sda2 * 274432 19406847 9566208 7 HPFS/NTFS/exFAT /dev/sda3 19406848 218274364 99433758+ 7 HPFS/NTFS/exFAT /dev/sda4 218275838 625139711 203431937 f W95 Ext'd (LBA) /dev/sda5 328630272 625139711 148254720 7 HPFS/NTFS/exFAT /dev/sda6 218275840 324030463 52877312 83 Linux /dev/sda7 324032512 328626175 2296832 82 Linux swap / Solaris Partition table entries are not in disk order =================== Repair blockers 64bits detected. Please use this software in a 64bits session. (Please use Ubuntu-Secure-Remix-64bits (www.sourceforge.net/p/ubuntu-secured) which contains a 64bits-compatible version of this software.) This will enable this feature. =================== Final advice in case of recommended repair The boot files of [Ubuntu 12.04.1 LTS] 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) =================== Default settings Recommended-Repair This setting would reinstall the grub2 of sda6 into the MBR of sda, using the following options: kernel-purge Additional repair would be performed: unhide-bootmenu-10s fix-windows-boot =================== Settings chosen by the user Boot-Info This setting will not act on the MBR. No change has been performed on your computer. See you soon! pastebinit packages needed dpkg-preconfigure: unable to re-open stdin: No such file or directory pastebin.com ko (), using paste.ubuntu Please report this message to [email protected] Any help would be great, I'm really missing Ubuntu (hate being stuck in the Windows world).

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  • Workaround the flip queue (AKA pre-rendered frames) in OpenGL?

    - by user41500
    It appears that some drivers implement a "flip queue" such that, even with vsync enabled, the first few calls to swap buffers return immediately (queuing those frames for later use). It is only after this queue is filled that buffer swaps will block to synchronize with vblank. This behavior is detrimental to my application. It creates latency. Does anyone know of a way to disable it or a workaround for dealing with it? The OpenGL Wiki on Swap Interval suggests a call to glFinish after the swap but I've had no such luck with that trick.

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  • Why does my RAID configuration with mdadm fail on reboots?

    - by Andy B
    I have been running Ubuntu server on my machine for 2 years and it has worked ok. I would like to speed it up by raiding a few drives. The machine is used to host my Mysql databases internally. using MDADM raid.. I have tried 2 schemes so far with the 3 drives. 2 partitions on each drive 1 for the swap 1 for the O/S both of them turned into drives raid level 5 3 partitions on each drive 1 for the boot 1 for the swap and 1 for the root. The boot I set to raid level1 and the swap and root raid drives were set to level5 Both setup worked fine for about a week, then on a reboot things fall apart. by fall apart I mean I end up with a bunch of hard drive errors on the screen and then get a grub prompt. Why do they fail on reboots? I am eager to understand what I am doing wrong thanks!

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  • Increase the /home partition without losing the data

    - by sagarchalise
    I have a 320 GB harddrive with three partitions / , /home and swap. What I want to do is change the size of swap which now is 8 GB to 5 GB and append that 3 GB to my /home partition. I have searched through the web for this but don't seem to find a proper way to increase my home partition. Can anyone help ? By the way, I know how to decrease size of swap I just need the proper way to append that unallocated 3 GB of space to my /home partition without loosing the data. Thank You

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  • How do I figure out the minimum number of swaps to sort a list in-place?

    - by sova
    In-place sorting is essentially swapping elements without using extra storage, correct? How can I find the minimum number of swaps required for a list? A C D Q R Z E // input | | | > > > <<< // movement A C D E Q R Z // output Swapping: A C D Q R Z E swap Q with E, ACDERZQ swap R with Q, ACDEQZR swap R with Z, ACDEQRZ. done. 3 swaps. Shifting items left or right is essentially swapping, but I want the optimal number for plucking an item out of line and switching its place with another.

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  • Aide On a Low Memory System

    - by Jason Mock
    I have a Linux server running on a Linode.com VPS, where I'm trying to utilize aide to detect any issues. However, the nightly aide run uses up all of my available memory and swap (512MB RAM / 384MB SWAP). I've tried adding a script to /etc/cron.daily that would stop/start services using a lot of memory (apache2, mysql) during the aide run. Unfortunately, it seems like aide continued to use every available byte (including the space freed up from apache2 and mysql). Here's a graph from munin showing what happens when aide runs: Note the spike of memory usage, well into swap, when aide runs Any suggestions on tuning aide to not use so much memory, or is there an alternative to aide that doesn't behave this way?

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  • Better way for calculating project euler's 2nd problem Fibonacci sequence)

    - by firephil
    object Problem_2 extends App { def fibLoop():Long = { var x = 1L var y = 2L var sum = 0L var swap = 0L while(x < 4000000) { if(x % 2 ==0) sum +=x swap = x x = y y = swap + x } sum } def fib:Int = { lazy val fs: Stream[Int] = 0 #:: 1 #:: fs.zip(fs.tail).map(p => p._1 + p._2) fs.view.takeWhile(_ <= 4000000).filter(_ % 2 == 0).sum } val t1 = System.nanoTime() val res = fibLoop val t2 = (System.nanoTime() - t1 )/1000 println(s"The result is: $res time taken $t2 ms ") } Is there a better functional way for calculating the fibonaci sequence and taking the sum of the the even values below 4million ? (projecteuler.net - problem 2) The imperative method is 1000x faster ?

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  • How do I edit keyboard preferences from the command line?

    - by jumpnett
    I want to swap the Caps Lock and Escape key as specified in this answer: Use the keyboard preferences to swap Caps Lock and Escape - seriously, how often do you use Caps Lock? Using vim you will be using Escape all the time, and having it available on the home row makes a huge difference. With the standard Ubuntu desktop, go through the menus: System - Preferences - Keyboard - Layouts tab. Then hit the "Layout Options" button, click on the triangle next to "Caps Lock key behaviour" and select "Swap ESC and CapsLock". but, I'm using Ubuntu Server with no gui, so how would I do this from the command line?

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  • creating extended partition

    - by SidhuHarry
    this is my current hard disk status(Running linux Mint LIVE CD) i have- Ubuntu 12.04 on 206 GB partition at dev/sda1. dev/sda2 system reserved. Windows 7 on 90GB partition at dev/sda3 and linux swap in extended partition. what i want to do- I want to install Linux mint KDE on my system for that i want to create a new partition of 30GB(by shrinking the free space available at dev/sda1), i can't create that because i can create only 4 Primary partitions which are already there. so do i have to delete the Swap partition? and if i did how to force Mint KDE and Ubuntu 12.04 to use/share same swap space in new logical partition?

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  • 'Multi' partition recipe from Ubuntu alternate install CD without preseed

    - by Nick Meyer
    The Ubuntu/Debian installer includes a built-in guided partitioning recipe, called 'multi', which creates separate /home, /usr, /var, and /tmp partitions. It can be selected by starting the installer with a preseed file. You can see it described in the Karmic install guide: # You can choose one of the three predefined partitioning recipes: # - atomic: all files in one partition # - home: separate /home partition # - multi: separate /home, /usr, /var, and /tmp partitions d-i partman-auto/choose_recipe select atomic Is there any way to use guided partitioning with this recipe from the Ubuntu alternate install CD without the need to create a preseed file?

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  • Automount of external hard disk

    - by moose
    I have an Intenso 6002560 1TB Memory Station - an external hard disk. This hard disk gets connected via Y-USB cable. When I connect both USB-ends to my Notebook, it gets recognized by my Ubuntu 10.04.4 LTS system: moose@pc07:~$ lsusb [...] Bus 002 Device 005: ID 13fd:1840 Initio Corporation [...] and Disk /dev/sda: 320.1 GB, 320072933376 bytes 255 heads, 63 sectors/track, 38913 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: 0x00065e10 Device Boot Start End Blocks Id System /dev/sda1 * 1 37810 303704064 83 Linux /dev/sda2 37810 38914 8864769 5 Extended /dev/sda5 37810 38914 8864768 82 Linux swap / Solaris Disk /dev/sdc: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, 121601 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: 0x0d6ea32a Device Boot Start End Blocks Id System /dev/sdc1 1 121601 976759008+ c W95 FAT32 (LBA) But it did not get mounted: moose@pc07:/dev$ mount -l /dev/sda1 on / type ext4 (rw,errors=remount-ro,user_xattr) proc on /proc type proc (rw,noexec,nosuid,nodev) none 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) none on /dev type devtmpfs (rw,mode=0755) none on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=0620) none on /dev/shm type tmpfs (rw,nosuid,nodev) none on /var/run type tmpfs (rw,nosuid,mode=0755) none on /var/lock type tmpfs (rw,noexec,nosuid,nodev) none on /lib/init/rw type tmpfs (rw,nosuid,mode=0755) binfmt_misc on /proc/sys/fs/binfmt_misc type binfmt_misc (rw,noexec,nosuid,nodev) gvfs-fuse-daemon on /home/moose/.gvfs type fuse.gvfs-fuse-daemon (rw,nosuid,nodev,user=moose) However, I could mount it manually with mount -t vfat /dev/sdc1 /mnt/sdc1 as you can see here: moose@pc07:~$ mount -l /dev/sda1 on / type ext4 (rw,errors=remount-ro,user_xattr) proc on /proc type proc (rw,noexec,nosuid,nodev) none 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) none on /dev type devtmpfs (rw,mode=0755) none on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=0620) none on /dev/shm type tmpfs (rw,nosuid,nodev) none on /var/run type tmpfs (rw,nosuid,mode=0755) none on /var/lock type tmpfs (rw,noexec,nosuid,nodev) none on /lib/init/rw type tmpfs (rw,nosuid,mode=0755) binfmt_misc on /proc/sys/fs/binfmt_misc type binfmt_misc (rw,noexec,nosuid,nodev) gvfs-fuse-daemon on /home/moose/.gvfs type fuse.gvfs-fuse-daemon (rw,nosuid,nodev,user=moose) /dev/sdc1 on /mnt/sdc1 type vfat (rw) edit: Another command: moose@pc07:~$ sudo blkid -o list device fs_type label mount point UUID ---------------------------------------------------------------------------------------------------------------------- /dev/sda1 ext4 / 45eb611b-517e-425b-8057-0391726cccd5 /dev/sda5 swap <swap> e9dc42f3-594c-4b62-874a-305eda5eed41 moose@pc07:~$ blkid -o list device fs_type label mount point UUID ---------------------------------------------------------------------------------------------------------------------- /dev/sda1 ext4 / 45eb611b-517e-425b-8057-0391726cccd5 /dev/sda5 swap <swap> e9dc42f3-594c-4b62-874a-305eda5eed41 /dev/sdc1 /mnt/sdc1 edit: another command: moose@pc07:~$ ls -l /dev/disk/by-uuid/ total 0 lrwxrwxrwx 1 root root 10 2012-09-30 09:31 45eb611b-517e-425b-8057-0391726cccd5 -> ../../sda1 lrwxrwxrwx 1 root root 10 2012-09-30 09:31 e9dc42f3-594c-4b62-874a-305eda5eed41 -> ../../sda5 Here is a link to a Launchpad question about this problem. But I would like it to mount automatically. What do I have to do?

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  • Can't boot in Ubuntu after windows upgrade

    - by VanceAnce
    After my lastest update for Ubuntu and Windows XP, I got a Grub error on booting the next day. ls lists the following (without () ): sd0 sd1, msdos sd2 sd5 sd6 When I tried to get into one with (sd0,xy)/ it doesn't detect system or unknown file system error. I tried to boot to a live session with a Knoppix live CD and found out that all data exists. I also tried to recover with TestDisk and it finds all systems. Here is the test disk result: Start End Size in sectors 1 * HPFS - NTFS 0 1 1 7079 254 63 113740137 2 E extended LBA 7080 0 1 12161 254 63 81642330 5 L HPFS - NTFS 7080 1 1 10266 254 63 51199092 [Schule] X extended 12031 30 1 12161 254 63 2102625 6 L Linux Swap 12031 31 33 12161 254 63 2102530 I've 1 winxp-home, 1x Ubuntu (ext3+swap) and 1 winxp prof and then I wrote on mbr with TestDisk but I always get the same errors with Grub. What should I do? I need both XP and Ubuntu. Help me please. more infos in answers below - sry for thos confusing style but im working on diff live system and browsers and have to reboot always the boot info script output is also down below maybe an advanced user can correct my fail posting - after i can solve my issuse i will register here thanx and pls help me with those weired issues ! as i still cant just comment my own answer or those on top i again has to put it here as a sepperate answer..... (or even edit - maybe an browser failur using the live cds ... cause this posti can edit) here the bootinfo script output - but the result is the same as with TestDisk ... but it looks worse - cause it also doesnt detect my old ubuntu ... but there wasnt a eares process or overwrite process visibile ending the last working session output: Boot Info Script 0.61 [1 April 2012] ============================= Boot Info Summary: =============================== = Syslinux MBR (4.04 and higher) is installed in the MBR of /dev/sda. sda1: __________________________________________ File system: ntfs Boot sector type: Windows XP: NTFS Boot sector info: No errors found in the Boot Parameter Block. Operating System: Windows XP Boot files: /boot.ini /ntldr /NTDETECT.COM sda2: __________________________________________ File system: Extended Partition Boot sector type: - Boot sector info: sda5: __________________________________________ File system: ntfs Boot sector type: Windows XP: NTFS Boot sector info: According to the info in the boot sector, sda5 starts at sector 63. Operating System: Windows XP Boot files: sda6: __________________________________________ File system: swap Boot sector type: - Boot sector info: ============================ Drive/Partition Info: ============================= Drive: sda _______________________________________ Disk /dev/sda: 100.0 GB, 100030242816 bytes 255 heads, 63 sectors/track, 12161 cylinders, total 195371568 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 * 63 113,740,199 113,740,137 7 NTFS / exFAT / HPFS /dev/sda2 113,740,200 195,382,529 81,642,330 f W95 Extended (LBA) /dev/sda5 113,740,263 164,939,354 51,199,092 7 NTFS / exFAT / HPFS /dev/sda6 193,280,000 195,382,529 2,102,530 82 Linux swap / Solaris /dev/sda2 ends after the last sector of /dev/sda /dev/sda6 ends after the last sector of /dev/sda "blkid" output: ____________________________________ Device UUID TYPE LABEL /dev/loop0 squashfs /dev/sda1 6596D86768011128 ntfs /dev/sda5 1300D3B7744EC141 ntfs Schule /dev/sda6 5b95f2a1-4145-43a5-ac51-41d7dd32b213 swap ================================ Mount points: ================================= Device Mount_Point Type Options /dev/loop0 /rofs squashfs (ro,noatime) /dev/sr0 /cdrom iso9660 (ro,noatime) ================================ sda1/boot.ini: ================================ [boot loader] timeout=30 default=multi(0)disk(0)rdisk(0)partition(1)\WINDOWS [operating systems] multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP Home Edition" /fastdetect /NoExecute=OptOut multi(0)disk(0)rdisk(0)partition(2)\WINDOWS="Microsoft Windows XP Professional" /fastdetect [spybotsd] timeout.old=30 the last part shows that i now use the windows boot loader so that i can acces at least one OS but shouldnt i also get acces to my ubuntu partitions with live-linux-cds ? or do i have to boot with grub to get to those files only ??

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  • Cross-platform, human-readable, du on root partition that truly ignores other filesystems

    - by nice_line
    I hate this so much: Linux builtsowell 2.6.18-274.7.1.el5 #1 SMP Mon Oct 17 11:57:14 EDT 2011 x86_64 x86_64 x86_64 GNU/Linux df -kh Filesystem Size Used Avail Use% Mounted on /dev/mapper/mpath0p2 8.8G 8.7G 90M 99% / /dev/mapper/mpath0p6 2.0G 37M 1.9G 2% /tmp /dev/mapper/mpath0p3 5.9G 670M 4.9G 12% /var /dev/mapper/mpath0p1 494M 86M 384M 19% /boot /dev/mapper/mpath0p7 7.3G 187M 6.7G 3% /home tmpfs 48G 6.2G 42G 14% /dev/shm /dev/mapper/o10g.bin 25G 7.4G 17G 32% /app/SIP/logs /dev/mapper/o11g.bin 25G 11G 14G 43% /o11g tmpfs 4.0K 0 4.0K 0% /dev/vx lunmonster1q:/vol/oradb_backup/epmxs1q1 686G 507G 180G 74% /rpmqa/backup lunmonster1q:/vol/oradb_redo/bisxs1q1 4.0G 1.6G 2.5G 38% /bisxs1q/rdoctl1 lunmonster1q:/vol/oradb_backup/bisxs1q1 686G 507G 180G 74% /bisxs1q/backup lunmonster1q:/vol/oradb_exp/bisxs1q1 2.0T 1.1T 984G 52% /bisxs1q/exp lunmonster2q:/vol/oradb_home/bisxs1q1 10G 174M 9.9G 2% /bisxs1q/home lunmonster2q:/vol/oradb_data/bisxs1q1 52G 5.2G 47G 10% /bisxs1q/oradata lunmonster1q:/vol/oradb_redo/bisxs1q2 4.0G 1.6G 2.5G 38% /bisxs1q/rdoctl2 ip-address1:/vol/oradb_home/cspxs1q1 10G 184M 9.9G 2% /cspxs1q/home ip-address2:/vol/oradb_backup/cspxs1q1 674G 314G 360G 47% /cspxs1q/backup ip-address2:/vol/oradb_redo/cspxs1q1 4.0G 1.5G 2.6G 37% /cspxs1q/rdoctl1 ip-address2:/vol/oradb_exp/cspxs1q1 4.1T 1.5T 2.6T 37% /cspxs1q/exp ip-address2:/vol/oradb_redo/cspxs1q2 4.0G 1.5G 2.6G 37% /cspxs1q/rdoctl2 ip-address1:/vol/oradb_data/cspxs1q1 160G 23G 138G 15% /cspxs1q/oradata lunmonster1q:/vol/oradb_exp/epmxs1q1 2.0T 1.1T 984G 52% /epmxs1q/exp lunmonster2q:/vol/oradb_home/epmxs1q1 10G 80M 10G 1% /epmxs1q/home lunmonster2q:/vol/oradb_data/epmxs1q1 330G 249G 82G 76% /epmxs1q/oradata lunmonster1q:/vol/oradb_redo/epmxs1q2 5.0G 609M 4.5G 12% /epmxs1q/rdoctl2 lunmonster1q:/vol/oradb_redo/epmxs1q1 5.0G 609M 4.5G 12% /epmxs1q/rdoctl1 /dev/vx/dsk/slaxs1q/slaxs1q-vol1 183G 17G 157G 10% /slaxs1q/backup /dev/vx/dsk/slaxs1q/slaxs1q-vol4 173G 58G 106G 36% /slaxs1q/oradata /dev/vx/dsk/slaxs1q/slaxs1q-vol5 75G 952M 71G 2% /slaxs1q/exp /dev/vx/dsk/slaxs1q/slaxs1q-vol2 9.8G 381M 8.9G 5% /slaxs1q/home /dev/vx/dsk/slaxs1q/slaxs1q-vol6 4.0G 1.6G 2.2G 42% /slaxs1q/rdoctl1 /dev/vx/dsk/slaxs1q/slaxs1q-vol3 4.0G 1.6G 2.2G 42% /slaxs1q/rdoctl2 /dev/mapper/appoem 30G 1.3G 27G 5% /app/em Yet, I equally, if not quite a bit more, also hate this: SunOS solarious 5.10 Generic_147440-19 sun4u sparc SUNW,SPARC-Enterprise Filesystem size used avail capacity Mounted on kiddie001Q_rpool/ROOT/s10s_u8wos_08a 8G 7.7G 1.3G 96% / /devices 0K 0K 0K 0% /devices ctfs 0K 0K 0K 0% /system/contract proc 0K 0K 0K 0% /proc mnttab 0K 0K 0K 0% /etc/mnttab swap 15G 1.8M 15G 1% /etc/svc/volatile objfs 0K 0K 0K 0% /system/object sharefs 0K 0K 0K 0% /etc/dfs/sharetab fd 0K 0K 0K 0% /dev/fd kiddie001Q_rpool/ROOT/s10s_u8wos_08a/var 31G 8.3G 6.6G 56% /var swap 512M 4.6M 507M 1% /tmp swap 15G 88K 15G 1% /var/run swap 15G 0K 15G 0% /dev/vx/dmp swap 15G 0K 15G 0% /dev/vx/rdmp /dev/dsk/c3t4d4s0 3 20G 279G 41G 88% /fs_storage /dev/vx/dsk/oracle/ora10g-vol1 292G 214G 73G 75% /o10g /dev/vx/dsk/oec/oec-vol1 64G 33G 31G 52% /oec/runway /dev/vx/dsk/oracle/ora9i-vol1 64G 33G 31G 59% /o9i /dev/vx/dsk/home 23G 18G 4.7G 80% /export/home /dev/vx/dsk/dbwork/dbwork-vol1 292G 214G 73G 92% /db03/wk01 /dev/vx/dsk/oradg/ebusredovol 2.0G 475M 1.5G 24% /u21 /dev/vx/dsk/oradg/ebusbckupvol 200G 32G 166G 17% /u31 /dev/vx/dsk/oradg/ebuscrtlvol 2.0G 475M 1.5G 24% /u20 kiddie001Q_rpool 31G 97K 6.6G 1% /kiddie001Q_rpool monsterfiler002q:/vol/ebiz_patches_nfs/NSA0304 203G 173G 29G 86% /oracle/patches /dev/odm 0K 0K 0K 0% /dev/odm The people with the authority don't rotate logs or delete packages after install in my environment. Standards, remediation, cohesion...all fancy foreign words to me. ============== How am I supposed to deal with / filesystem full issues across multiple platforms that have a devastating number of mounts? On Red Hat el5, du -x apparently avoids traversal into other filesystems. While this may be so, it does not appear to do anything if run from the / directory. On Solaris 10, the equivalent flag is du -d, which apparently packs no surprises, allowing Sun to uphold its legacy of inconvenience effortlessly. (I'm hoping I've just been doing it wrong.) I offer up for sacrifice my Frankenstein's monster. Tell me how ugly it is. Tell me I should download forbidden 3rd party software. Tell me I should perform unauthorized coreutils updates, piecemeal, across 2000 systems, with no single sign-on, no authorized keys, and no network update capability. Then, please help me make this bastard better: pwd / du * | egrep -v "$(echo $(df | awk '{print $1 "\n" $5 "\n" $6}' | \ cut -d\/ -f2-5 | egrep -v "[0-9]|^$|Filesystem|Use|Available|Mounted|blocks|vol|swap")| \ sed 's/ /\|/g')" | egrep -v "proc|sys|media|selinux|dev|platform|system|tmp|tmpfs|mnt|kernel" | \ cut -d\/ -f1-2 | sort -k2 -k1,1nr | uniq -f1 | sort -k1,1n | cut -f2 | xargs du -shx | \ egrep "G|[5-9][0-9]M|[1-9][0-9][0-9]M" My biggest failure and regret is that it still requires a single character edit for Solaris: pwd / du * | egrep -v "$(echo $(df | awk '{print $1 "\n" $5 "\n" $6}' | \ cut -d\/ -f2-5 | egrep -v "[0-9]|^$|Filesystem|Use|Available|Mounted|blocks|vol|swap")| \ sed 's/ /\|/g')" | egrep -v "proc|sys|media|selinux|dev|platform|system|tmp|tmpfs|mnt|kernel" | \ cut -d\/ -f1-2 | sort -k2 -k1,1nr | uniq -f1 | sort -k1,1n | cut -f2 | xargs du -shd | \ egrep "G|[5-9][0-9]M|[1-9][0-9][0-9]M" This will exclude all non / filesystems in a du search from the / directory by basically munging an egrepped df from a second pipe-delimited egrep regex subshell exclusion that is naturally further excluded upon by a third egrep in what I would like to refer to as "the whale." The munge-fest frantically escalates into some xargs du recycling where -x/-d is actually useful, and a final, gratuitous egrep spits out a list of directories that almost feels like an accomplishment: Linux: 54M etc/gconf 61M opt/quest 77M opt 118M usr/ ##===\ 149M etc 154M root 303M lib/modules 313M usr/java ##====\ 331M lib 357M usr/lib64 ##=====\ 433M usr/lib ##========\ 1.1G usr/share ##=======\ 3.2G usr/local ##========\ 5.4G usr ##<=============Ascending order to parent 94M app/SIP ##<==\ 94M app ##<=======Were reported as 7gb and then corrected by second du with -x. Solaris: 63M etc 490M bb 570M root/cores.ric.20100415 1.7G oec/archive 1.1G root/packages 2.2G root 1.7G oec Guess what? It's really slow. Edit: Are there any bash one-liner heroes out there than can turn my bloated abomination into divine intervention, or at least something resembling gingerly copypasta?

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  • about Quick Sort

    - by matin1234
    Hi I have written this code but it will print these stack traces in the console please help me thanks! (Aslo "p" and "q" are the first and last index of our array ,respectively) public class JavaQuickSort { public static void QuickSort(int A[], int p, int q) { int i, last = 0; Random rand = new Random(); if (q < 1) { return; } **swap(A, p, rand.nextInt() % (q+1));** for (i = p + 1; i <= q; i++) { if (A[i] < A[p]) { swap(A, ++last, i); } } swap(A, p, last); QuickSort(A, p, last - 1); QuickSort(A, last + 1, q); } private static void swap(int[] A, int i, int j) { int temp; temp = A[i]; **A[i] = A[j];** A[j] = temp; } public static void main(String[] args){ int[] A = {2,5,7,3,9,0,1,6,8}; **QuickSort(A, 0,8 );** System.out.println(Arrays.toString(A)); } } the Stack traces : run: Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: -3 at JavaQuickSort.swap(JavaQuickSort.java:38) at JavaQuickSort.QuickSort(JavaQuickSort.java:22) at JavaQuickSort.main(JavaQuickSort.java:45) Java Result: 1 BUILD SUCCESSFUL (total time: 2 seconds) I also bold those statements that cause these stack traces. like == ** ...**

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  • An Ideal Keyboard Layout for Programming

    - by Jon Purdy
    I often hear complaints that programming languages that make heavy use of symbols for brevity, most notably C and C++ (I'm not going to touch APL), are difficult to type because they require frequent use of the shift key. A year or two ago, I got tired of it myself, downloaded Microsoft's Keyboard Layout Creator, made a few changes to my layout, and have not once looked back. The speed difference is astounding; with these few simple changes I am able to type C++ code around 30% faster, depending of course on how hairy it is; best of all, my typing speed in ordinary running text is not compromised. My questions are these: what alternate keyboard layouts have existed for programming, which have gained popularity, are any of them still in modern use, do you personally use any altered layout, and how can my layout be further optimised? I made the following changes to a standard QWERTY layout. (I don't use Dvorak, but there is a programmer Dvorak layout worth mentioning.) Swap numbers with symbols in the top row, because long or repeated literal numbers are typically replaced with named constants; Swap backquote with tilde, because backquotes are rare in many languages but destructors are common in C++; Swap minus with underscore, because underscores are common in identifiers; Swap curly braces with square brackets, because blocks are more common than subscripts; and Swap double quote with single quote, because strings are more common than character literals. I suspect this last is probably going to be the most controversial, as it interferes the most with running text by requiring use of shift to type common contractions. This layout has significantly increased my typing speed in C++, C, Java, and Perl, and somewhat increased it in LISP and Python.

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  • What is the proper way to declare a specialization of a template for another template type?

    - by Head Geek
    The usual definition for a specialization of a template function is something like this: class Foo { [...] }; namespace std { template<> void swap(Foo& left, Foo& right) { [...] } } // namespace std But how do you properly define the specialization when the type it's specialized on is itself a template? Here's what I've got: template <size_t Bits> class fixed { [...] }; namespace std { template<size_t Bits> void swap(fixed<Bits>& left, fixed<Bits>& right) { [...] } } // namespace std Is this the right way to declare swap? It's supposed to be a specialization of the template function std::swap, but I can't tell whether the compiler is seeing it as such, or whether it thinks that it's an overload of it or something.

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  • Removing elements from heap

    - by user193138
    I made a heap. I am curious if there's something subtley wrong with my remove function: int Heap::remove() { if (n == 0) exit(1); int temp = arr[0]; arr[0] = arr[--n]; heapDown(0); arr[n] = 0; return temp; } void Heap::heapDown(int i) { int l = left(i); int r = right(i); // comparing parent to left/right child // each has an inner if to handle if the first swap causes a second swap // ie 1 -> 3 -> 5 // 3 5 1 5 1 3 if (l < n && arr[i] < arr[l]) { swap(arr[i], arr[l]); heapDown(l); if (r < n && arr[i] < arr[r]) { swap(arr[i], arr[r]); heapDown(r); } } else if (r < n && arr[i] < arr[r]) { swap(arr[i], arr[r]); heapDown(r); if (l < n && arr[i] < arr[l]) { swap(arr[i], arr[l]); heapDown(l); } } } Here's my output i1i2i3i4i5i6i7 p Active heap: 7 4 6 1 3 2 5 r Removed 7 r Removed 6 p Active heap: 5 3 4 1 2 Here's my teacher's sample output: p Active heap : 7 4 6 1 3 2 5 r Removed 7 r Removed 6 p Active heap : 5 4 2 1 3 s Heapsorted : 1 2 3 4 5 While our outputs are completely different, I do seem to hold maxheap principle of having everything left oriented and for all nodes parent child(in every case I tried). I try to do algs like this from scratch, so maybe I'm just doing something really weird and wrong (I would only consider it "wrong" if it's O(lg n), as removes are intended to be for heaps). Is there anything in particular "wrong" about my remove? Thanks, http://ideone.com/PPh4eQ

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  • Access violation in DirectX OMSetRenderTargets

    - by IDWMaster
    I receive the following error (Unhandled exception at 0x527DAE81 (d3d11_1sdklayers.dll) in Lesson2.Triangles.exe: 0xC0000005: Access violation reading location 0x00000000) when running the Triangle sample application for DirectX 11 in D3D_FEATURE_LEVEL_9_1. This error occurs at the OMSetRenderTargets function, as shown below, and does not happen if I remove that function from the program (but then, the screen is blue, and does not render the triangle) //// THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF //// ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO //// THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A //// PARTICULAR PURPOSE. //// //// Copyright (c) Microsoft Corporation. All rights reserved #include #include #include "DirectXSample.h" #include "BasicMath.h" #include "BasicReaderWriter.h" using namespace Microsoft::WRL; using namespace Windows::UI::Core; using namespace Windows::Foundation; using namespace Windows::ApplicationModel::Core; using namespace Windows::ApplicationModel::Infrastructure; // This class defines the application as a whole. ref class Direct3DTutorialViewProvider : public IViewProvider { private: CoreWindow^ m_window; ComPtr m_swapChain; ComPtr m_d3dDevice; ComPtr m_d3dDeviceContext; ComPtr m_renderTargetView; public: // This method is called on application launch. void Initialize( _In_ CoreWindow^ window, _In_ CoreApplicationView^ applicationView ) { m_window = window; } // This method is called after Initialize. void Load(_In_ Platform::String^ entryPoint) { } // This method is called after Load. void Run() { // First, create the Direct3D device. // This flag is required in order to enable compatibility with Direct2D. UINT creationFlags = D3D11_CREATE_DEVICE_BGRA_SUPPORT; #if defined(_DEBUG) // If the project is in a debug build, enable debugging via SDK Layers with this flag. creationFlags |= D3D11_CREATE_DEVICE_DEBUG; #endif // This array defines the ordering of feature levels that D3D should attempt to create. D3D_FEATURE_LEVEL featureLevels[] = { D3D_FEATURE_LEVEL_11_1, D3D_FEATURE_LEVEL_11_0, D3D_FEATURE_LEVEL_10_1, D3D_FEATURE_LEVEL_10_0, D3D_FEATURE_LEVEL_9_3, D3D_FEATURE_LEVEL_9_1 }; ComPtr d3dDevice; ComPtr d3dDeviceContext; DX::ThrowIfFailed( D3D11CreateDevice( nullptr, // specify nullptr to use the default adapter D3D_DRIVER_TYPE_HARDWARE, nullptr, // leave as nullptr if hardware is used creationFlags, // optionally set debug and Direct2D compatibility flags featureLevels, ARRAYSIZE(featureLevels), D3D11_SDK_VERSION, // always set this to D3D11_SDK_VERSION &d3dDevice, nullptr, &d3dDeviceContext ) ); // Retrieve the Direct3D 11.1 interfaces. DX::ThrowIfFailed( d3dDevice.As(&m_d3dDevice) ); DX::ThrowIfFailed( d3dDeviceContext.As(&m_d3dDeviceContext) ); // After the D3D device is created, create additional application resources. CreateWindowSizeDependentResources(); // Create a Basic Reader-Writer class to load data from disk. This class is examined // in the Resource Loading sample. BasicReaderWriter^ reader = ref new BasicReaderWriter(); // Load the raw vertex shader bytecode from disk and create a vertex shader with it. auto vertexShaderBytecode = reader-ReadData("SimpleVertexShader.cso"); ComPtr vertexShader; DX::ThrowIfFailed( m_d3dDevice-CreateVertexShader( vertexShaderBytecode-Data, vertexShaderBytecode-Length, nullptr, &vertexShader ) ); // Create an input layout that matches the layout defined in the vertex shader code. // For this lesson, this is simply a float2 vector defining the vertex position. const D3D11_INPUT_ELEMENT_DESC basicVertexLayoutDesc[] = { { "POSITION", 0, DXGI_FORMAT_R32G32_FLOAT, 0, 0, D3D11_INPUT_PER_VERTEX_DATA, 0 }, }; ComPtr inputLayout; DX::ThrowIfFailed( m_d3dDevice-CreateInputLayout( basicVertexLayoutDesc, ARRAYSIZE(basicVertexLayoutDesc), vertexShaderBytecode-Data, vertexShaderBytecode-Length, &inputLayout ) ); // Load the raw pixel shader bytecode from disk and create a pixel shader with it. auto pixelShaderBytecode = reader-ReadData("SimplePixelShader.cso"); ComPtr pixelShader; DX::ThrowIfFailed( m_d3dDevice-CreatePixelShader( pixelShaderBytecode-Data, pixelShaderBytecode-Length, nullptr, &pixelShader ) ); // Create vertex and index buffers that define a simple triangle. float3 triangleVertices[] = { float3(-0.5f, -0.5f,13.5f), float3( 0.0f, 0.5f,0), float3( 0.5f, -0.5f,0), }; D3D11_BUFFER_DESC vertexBufferDesc = {0}; vertexBufferDesc.ByteWidth = sizeof(float3) * ARRAYSIZE(triangleVertices); vertexBufferDesc.Usage = D3D11_USAGE_DEFAULT; vertexBufferDesc.BindFlags = D3D11_BIND_VERTEX_BUFFER; vertexBufferDesc.CPUAccessFlags = 0; vertexBufferDesc.MiscFlags = 0; vertexBufferDesc.StructureByteStride = 0; D3D11_SUBRESOURCE_DATA vertexBufferData; vertexBufferData.pSysMem = triangleVertices; vertexBufferData.SysMemPitch = 0; vertexBufferData.SysMemSlicePitch = 0; ComPtr vertexBuffer; DX::ThrowIfFailed( m_d3dDevice-CreateBuffer( &vertexBufferDesc, &vertexBufferData, &vertexBuffer ) ); // Once all D3D resources are created, configure the application window. // Allow the application to respond when the window size changes. m_window-SizeChanged += ref new TypedEventHandler( this, &Direct3DTutorialViewProvider::OnWindowSizeChanged ); // Specify the cursor type as the standard arrow cursor. m_window-PointerCursor = ref new CoreCursor(CoreCursorType::Arrow, 0); // Activate the application window, making it visible and enabling it to receive events. m_window-Activate(); // Enter the render loop. Note that tailored applications should never exit. while (true) { // Process events incoming to the window. m_window-Dispatcher-ProcessEvents(CoreProcessEventsOption::ProcessAllIfPresent); // Specify the render target we created as the output target. ID3D11RenderTargetView* targets[1] = {m_renderTargetView.Get()}; m_d3dDeviceContext-OMSetRenderTargets( 1, targets, NULL // use no depth stencil ); // Clear the render target to a solid color. const float clearColor[4] = { 0.071f, 0.04f, 0.561f, 1.0f }; //Code fails here m_d3dDeviceContext-ClearRenderTargetView( m_renderTargetView.Get(), clearColor ); m_d3dDeviceContext-IASetInputLayout(inputLayout.Get()); // Set the vertex and index buffers, and specify the way they define geometry. UINT stride = sizeof(float3); UINT offset = 0; m_d3dDeviceContext-IASetVertexBuffers( 0, 1, vertexBuffer.GetAddressOf(), &stride, &offset ); m_d3dDeviceContext-IASetPrimitiveTopology(D3D11_PRIMITIVE_TOPOLOGY_TRIANGLELIST); // Set the vertex and pixel shader stage state. m_d3dDeviceContext-VSSetShader( vertexShader.Get(), nullptr, 0 ); m_d3dDeviceContext-PSSetShader( pixelShader.Get(), nullptr, 0 ); // Draw the cube. m_d3dDeviceContext-Draw(3,0); // Present the rendered image to the window. Because the maximum frame latency is set to 1, // the render loop will generally be throttled to the screen refresh rate, typically around // 60Hz, by sleeping the application on Present until the screen is refreshed. DX::ThrowIfFailed( m_swapChain-Present(1, 0) ); } } // This method is called before the application exits. void Uninitialize() { } private: // This method is called whenever the application window size changes. void OnWindowSizeChanged( _In_ CoreWindow^ sender, _In_ WindowSizeChangedEventArgs^ args ) { m_renderTargetView = nullptr; CreateWindowSizeDependentResources(); } // This method creates all application resources that depend on // the application window size. It is called at app initialization, // and whenever the application window size changes. void CreateWindowSizeDependentResources() { if (m_swapChain != nullptr) { // If the swap chain already exists, resize it. DX::ThrowIfFailed( m_swapChain-ResizeBuffers( 2, 0, 0, DXGI_FORMAT_R8G8B8A8_UNORM, 0 ) ); } else { // If the swap chain does not exist, create it. DXGI_SWAP_CHAIN_DESC1 swapChainDesc = {0}; swapChainDesc.Stereo = false; swapChainDesc.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT; swapChainDesc.Scaling = DXGI_SCALING_NONE; swapChainDesc.Flags = 0; // Use automatic sizing. swapChainDesc.Width = 0; swapChainDesc.Height = 0; // This is the most common swap chain format. swapChainDesc.Format = DXGI_FORMAT_R8G8B8A8_UNORM; // Don't use multi-sampling. swapChainDesc.SampleDesc.Count = 1; swapChainDesc.SampleDesc.Quality = 0; // Use two buffers to enable flip effect. swapChainDesc.BufferCount = 2; // We recommend using this swap effect for all applications. swapChainDesc.SwapEffect = DXGI_SWAP_EFFECT_FLIP_SEQUENTIAL; // Once the swap chain description is configured, it must be // created on the same adapter as the existing D3D Device. // First, retrieve the underlying DXGI Device from the D3D Device. ComPtr dxgiDevice; DX::ThrowIfFailed( m_d3dDevice.As(&dxgiDevice) ); // Ensure that DXGI does not queue more than one frame at a time. This both reduces // latency and ensures that the application will only render after each VSync, minimizing // power consumption. DX::ThrowIfFailed( dxgiDevice-SetMaximumFrameLatency(1) ); // Next, get the parent factory from the DXGI Device. ComPtr dxgiAdapter; DX::ThrowIfFailed( dxgiDevice-GetAdapter(&dxgiAdapter) ); ComPtr dxgiFactory; DX::ThrowIfFailed( dxgiAdapter-GetParent( __uuidof(IDXGIFactory2), &dxgiFactory ) ); // Finally, create the swap chain. DX::ThrowIfFailed( dxgiFactory-CreateSwapChainForImmersiveWindow( m_d3dDevice.Get(), DX::GetIUnknown(m_window), &swapChainDesc, nullptr, // allow on all displays &m_swapChain ) ); } // Once the swap chain is created, create a render target view. This will // allow Direct3D to render graphics to the window. ComPtr backBuffer; DX::ThrowIfFailed( m_swapChain-GetBuffer( 0, __uuidof(ID3D11Texture2D), &backBuffer ) ); DX::ThrowIfFailed( m_d3dDevice-CreateRenderTargetView( backBuffer.Get(), nullptr, &m_renderTargetView ) ); // After the render target view is created, specify that the viewport, // which describes what portion of the window to draw to, should cover // the entire window. D3D11_TEXTURE2D_DESC backBufferDesc = {0}; backBuffer-GetDesc(&backBufferDesc); D3D11_VIEWPORT viewport; viewport.TopLeftX = 0.0f; viewport.TopLeftY = 0.0f; viewport.Width = static_cast(backBufferDesc.Width); viewport.Height = static_cast(backBufferDesc.Height); viewport.MinDepth = D3D11_MIN_DEPTH; viewport.MaxDepth = D3D11_MAX_DEPTH; m_d3dDeviceContext-RSSetViewports(1, &viewport); } }; // This class defines how to create the custom View Provider defined above. ref class Direct3DTutorialViewProviderFactory : IViewProviderFactory { public: IViewProvider^ CreateViewProvider() { return ref new Direct3DTutorialViewProvider(); } }; [Platform::MTAThread] int main(array^) { auto viewProviderFactory = ref new Direct3DTutorialViewProviderFactory(); Windows::ApplicationModel::Core::CoreApplication::Run(viewProviderFactory); return 0; }

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  • C#/.NET Little Wonders: The Concurrent Collections (1 of 3)

    - by James Michael Hare
    Once again we consider some of the lesser known classes and keywords of C#.  In the next few weeks, we will discuss the concurrent collections and how they have changed the face of concurrent programming. This week’s post will begin with a general introduction and discuss the ConcurrentStack<T> and ConcurrentQueue<T>.  Then in the following post we’ll discuss the ConcurrentDictionary<T> and ConcurrentBag<T>.  Finally, we shall close on the third post with a discussion of the BlockingCollection<T>. For more of the "Little Wonders" posts, see the index here. A brief history of collections In the beginning was the .NET 1.0 Framework.  And out of this framework emerged the System.Collections namespace, and it was good.  It contained all the basic things a growing programming language needs like the ArrayList and Hashtable collections.  The main problem, of course, with these original collections is that they held items of type object which means you had to be disciplined enough to use them correctly or you could end up with runtime errors if you got an object of a type you weren't expecting. Then came .NET 2.0 and generics and our world changed forever!  With generics the C# language finally got an equivalent of the very powerful C++ templates.  As such, the System.Collections.Generic was born and we got type-safe versions of all are favorite collections.  The List<T> succeeded the ArrayList and the Dictionary<TKey,TValue> succeeded the Hashtable and so on.  The new versions of the library were not only safer because they checked types at compile-time, in many cases they were more performant as well.  So much so that it's Microsoft's recommendation that the System.Collections original collections only be used for backwards compatibility. So we as developers came to know and love the generic collections and took them into our hearts and embraced them.  The problem is, thread safety in both the original collections and the generic collections can be problematic, for very different reasons. Now, if you are only doing single-threaded development you may not care – after all, no locking is required.  Even if you do have multiple threads, if a collection is “load-once, read-many” you don’t need to do anything to protect that container from multi-threaded access, as illustrated below: 1: public static class OrderTypeTranslator 2: { 3: // because this dictionary is loaded once before it is ever accessed, we don't need to synchronize 4: // multi-threaded read access 5: private static readonly Dictionary<string, char> _translator = new Dictionary<string, char> 6: { 7: {"New", 'N'}, 8: {"Update", 'U'}, 9: {"Cancel", 'X'} 10: }; 11:  12: // the only public interface into the dictionary is for reading, so inherently thread-safe 13: public static char? Translate(string orderType) 14: { 15: char charValue; 16: if (_translator.TryGetValue(orderType, out charValue)) 17: { 18: return charValue; 19: } 20:  21: return null; 22: } 23: } Unfortunately, most of our computer science problems cannot get by with just single-threaded applications or with multi-threading in a load-once manner.  Looking at  today's trends, it's clear to see that computers are not so much getting faster because of faster processor speeds -- we've nearly reached the limits we can push through with today's technologies -- but more because we're adding more cores to the boxes.  With this new hardware paradigm, it is even more important to use multi-threaded applications to take full advantage of parallel processing to achieve higher application speeds. So let's look at how to use collections in a thread-safe manner. Using historical collections in a concurrent fashion The early .NET collections (System.Collections) had a Synchronized() static method that could be used to wrap the early collections to make them completely thread-safe.  This paradigm was dropped in the generic collections (System.Collections.Generic) because having a synchronized wrapper resulted in atomic locks for all operations, which could prove overkill in many multithreading situations.  Thus the paradigm shifted to having the user of the collection specify their own locking, usually with an external object: 1: public class OrderAggregator 2: { 3: private static readonly Dictionary<string, List<Order>> _orders = new Dictionary<string, List<Order>>(); 4: private static readonly _orderLock = new object(); 5:  6: public void Add(string accountNumber, Order newOrder) 7: { 8: List<Order> ordersForAccount; 9:  10: // a complex operation like this should all be protected 11: lock (_orderLock) 12: { 13: if (!_orders.TryGetValue(accountNumber, out ordersForAccount)) 14: { 15: _orders.Add(accountNumber, ordersForAccount = new List<Order>()); 16: } 17:  18: ordersForAccount.Add(newOrder); 19: } 20: } 21: } Notice how we’re performing several operations on the dictionary under one lock.  With the Synchronized() static methods of the early collections, you wouldn’t be able to specify this level of locking (a more macro-level).  So in the generic collections, it was decided that if a user needed synchronization, they could implement their own locking scheme instead so that they could provide synchronization as needed. The need for better concurrent access to collections Here’s the problem: it’s relatively easy to write a collection that locks itself down completely for access, but anything more complex than that can be difficult and error-prone to write, and much less to make it perform efficiently!  For example, what if you have a Dictionary that has frequent reads but in-frequent updates?  Do you want to lock down the entire Dictionary for every access?  This would be overkill and would prevent concurrent reads.  In such cases you could use something like a ReaderWriterLockSlim which allows for multiple readers in a lock, and then once a writer grabs the lock it blocks all further readers until the writer is done (in a nutshell).  This is all very complex stuff to consider. Fortunately, this is where the Concurrent Collections come in.  The Parallel Computing Platform team at Microsoft went through great pains to determine how to make a set of concurrent collections that would have the best performance characteristics for general case multi-threaded use. Now, as in all things involving threading, you should always make sure you evaluate all your container options based on the particular usage scenario and the degree of parallelism you wish to acheive. This article should not be taken to understand that these collections are always supperior to the generic collections. Each fills a particular need for a particular situation. Understanding what each container is optimized for is key to the success of your application whether it be single-threaded or multi-threaded. General points to consider with the concurrent collections The MSDN points out that the concurrent collections all support the ICollection interface. However, since the collections are already synchronized, the IsSynchronized property always returns false, and SyncRoot always returns null.  Thus you should not attempt to use these properties for synchronization purposes. Note that since the concurrent collections also may have different operations than the traditional data structures you may be used to.  Now you may ask why they did this, but it was done out of necessity to keep operations safe and atomic.  For example, in order to do a Pop() on a stack you have to know the stack is non-empty, but between the time you check the stack’s IsEmpty property and then do the Pop() another thread may have come in and made the stack empty!  This is why some of the traditional operations have been changed to make them safe for concurrent use. In addition, some properties and methods in the concurrent collections achieve concurrency by creating a snapshot of the collection, which means that some operations that were traditionally O(1) may now be O(n) in the concurrent models.  I’ll try to point these out as we talk about each collection so you can be aware of any potential performance impacts.  Finally, all the concurrent containers are safe for enumeration even while being modified, but some of the containers support this in different ways (snapshot vs. dirty iteration).  Once again I’ll highlight how thread-safe enumeration works for each collection. ConcurrentStack<T>: The thread-safe LIFO container The ConcurrentStack<T> is the thread-safe counterpart to the System.Collections.Generic.Stack<T>, which as you may remember is your standard last-in-first-out container.  If you think of algorithms that favor stack usage (for example, depth-first searches of graphs and trees) then you can see how using a thread-safe stack would be of benefit. The ConcurrentStack<T> achieves thread-safe access by using System.Threading.Interlocked operations.  This means that the multi-threaded access to the stack requires no traditional locking and is very, very fast! For the most part, the ConcurrentStack<T> behaves like it’s Stack<T> counterpart with a few differences: Pop() was removed in favor of TryPop() Returns true if an item existed and was popped and false if empty. PushRange() and TryPopRange() were added Allows you to push multiple items and pop multiple items atomically. Count takes a snapshot of the stack and then counts the items. This means it is a O(n) operation, if you just want to check for an empty stack, call IsEmpty instead which is O(1). ToArray() and GetEnumerator() both also take snapshots. This means that iteration over a stack will give you a static view at the time of the call and will not reflect updates. Pushing on a ConcurrentStack<T> works just like you’d expect except for the aforementioned PushRange() method that was added to allow you to push a range of items concurrently. 1: var stack = new ConcurrentStack<string>(); 2:  3: // adding to stack is much the same as before 4: stack.Push("First"); 5:  6: // but you can also push multiple items in one atomic operation (no interleaves) 7: stack.PushRange(new [] { "Second", "Third", "Fourth" }); For looking at the top item of the stack (without removing it) the Peek() method has been removed in favor of a TryPeek().  This is because in order to do a peek the stack must be non-empty, but between the time you check for empty and the time you execute the peek the stack contents may have changed.  Thus the TryPeek() was created to be an atomic check for empty, and then peek if not empty: 1: // to look at top item of stack without removing it, can use TryPeek. 2: // Note that there is no Peek(), this is because you need to check for empty first. TryPeek does. 3: string item; 4: if (stack.TryPeek(out item)) 5: { 6: Console.WriteLine("Top item was " + item); 7: } 8: else 9: { 10: Console.WriteLine("Stack was empty."); 11: } Finally, to remove items from the stack, we have the TryPop() for single, and TryPopRange() for multiple items.  Just like the TryPeek(), these operations replace Pop() since we need to ensure atomically that the stack is non-empty before we pop from it: 1: // to remove items, use TryPop or TryPopRange to get multiple items atomically (no interleaves) 2: if (stack.TryPop(out item)) 3: { 4: Console.WriteLine("Popped " + item); 5: } 6:  7: // TryPopRange will only pop up to the number of spaces in the array, the actual number popped is returned. 8: var poppedItems = new string[2]; 9: int numPopped = stack.TryPopRange(poppedItems); 10:  11: foreach (var theItem in poppedItems.Take(numPopped)) 12: { 13: Console.WriteLine("Popped " + theItem); 14: } Finally, note that as stated before, GetEnumerator() and ToArray() gets a snapshot of the data at the time of the call.  That means if you are enumerating the stack you will get a snapshot of the stack at the time of the call.  This is illustrated below: 1: var stack = new ConcurrentStack<string>(); 2:  3: // adding to stack is much the same as before 4: stack.Push("First"); 5:  6: var results = stack.GetEnumerator(); 7:  8: // but you can also push multiple items in one atomic operation (no interleaves) 9: stack.PushRange(new [] { "Second", "Third", "Fourth" }); 10:  11: while(results.MoveNext()) 12: { 13: Console.WriteLine("Stack only has: " + results.Current); 14: } The only item that will be printed out in the above code is "First" because the snapshot was taken before the other items were added. This may sound like an issue, but it’s really for safety and is more correct.  You don’t want to enumerate a stack and have half a view of the stack before an update and half a view of the stack after an update, after all.  In addition, note that this is still thread-safe, whereas iterating through a non-concurrent collection while updating it in the old collections would cause an exception. ConcurrentQueue<T>: The thread-safe FIFO container The ConcurrentQueue<T> is the thread-safe counterpart of the System.Collections.Generic.Queue<T> class.  The concurrent queue uses an underlying list of small arrays and lock-free System.Threading.Interlocked operations on the head and tail arrays.  Once again, this allows us to do thread-safe operations without the need for heavy locks! The ConcurrentQueue<T> (like the ConcurrentStack<T>) has some departures from the non-concurrent counterpart.  Most notably: Dequeue() was removed in favor of TryDequeue(). Returns true if an item existed and was dequeued and false if empty. Count does not take a snapshot It subtracts the head and tail index to get the count.  This results overall in a O(1) complexity which is quite good.  It’s still recommended, however, that for empty checks you call IsEmpty instead of comparing Count to zero. ToArray() and GetEnumerator() both take snapshots. This means that iteration over a queue will give you a static view at the time of the call and will not reflect updates. The Enqueue() method on the ConcurrentQueue<T> works much the same as the generic Queue<T>: 1: var queue = new ConcurrentQueue<string>(); 2:  3: // adding to queue is much the same as before 4: queue.Enqueue("First"); 5: queue.Enqueue("Second"); 6: queue.Enqueue("Third"); For front item access, the TryPeek() method must be used to attempt to see the first item if the queue.  There is no Peek() method since, as you’ll remember, we can only peek on a non-empty queue, so we must have an atomic TryPeek() that checks for empty and then returns the first item if the queue is non-empty. 1: // to look at first item in queue without removing it, can use TryPeek. 2: // Note that there is no Peek(), this is because you need to check for empty first. TryPeek does. 3: string item; 4: if (queue.TryPeek(out item)) 5: { 6: Console.WriteLine("First item was " + item); 7: } 8: else 9: { 10: Console.WriteLine("Queue was empty."); 11: } Then, to remove items you use TryDequeue().  Once again this is for the same reason we have TryPeek() and not Peek(): 1: // to remove items, use TryDequeue. If queue is empty returns false. 2: if (queue.TryDequeue(out item)) 3: { 4: Console.WriteLine("Dequeued first item " + item); 5: } Just like the concurrent stack, the ConcurrentQueue<T> takes a snapshot when you call ToArray() or GetEnumerator() which means that subsequent updates to the queue will not be seen when you iterate over the results.  Thus once again the code below will only show the first item, since the other items were added after the snapshot. 1: var queue = new ConcurrentQueue<string>(); 2:  3: // adding to queue is much the same as before 4: queue.Enqueue("First"); 5:  6: var iterator = queue.GetEnumerator(); 7:  8: queue.Enqueue("Second"); 9: queue.Enqueue("Third"); 10:  11: // only shows First 12: while (iterator.MoveNext()) 13: { 14: Console.WriteLine("Dequeued item " + iterator.Current); 15: } Using collections concurrently You’ll notice in the examples above I stuck to using single-threaded examples so as to make them deterministic and the results obvious.  Of course, if we used these collections in a truly multi-threaded way the results would be less deterministic, but would still be thread-safe and with no locking on your part required! For example, say you have an order processor that takes an IEnumerable<Order> and handles each other in a multi-threaded fashion, then groups the responses together in a concurrent collection for aggregation.  This can be done easily with the TPL’s Parallel.ForEach(): 1: public static IEnumerable<OrderResult> ProcessOrders(IEnumerable<Order> orderList) 2: { 3: var proxy = new OrderProxy(); 4: var results = new ConcurrentQueue<OrderResult>(); 5:  6: // notice that we can process all these in parallel and put the results 7: // into our concurrent collection without needing any external locking! 8: Parallel.ForEach(orderList, 9: order => 10: { 11: var result = proxy.PlaceOrder(order); 12:  13: results.Enqueue(result); 14: }); 15:  16: return results; 17: } Summary Obviously, if you do not need multi-threaded safety, you don’t need to use these collections, but when you do need multi-threaded collections these are just the ticket! The plethora of features (I always think of the movie The Three Amigos when I say plethora) built into these containers and the amazing way they acheive thread-safe access in an efficient manner is wonderful to behold. Stay tuned next week where we’ll continue our discussion with the ConcurrentBag<T> and the ConcurrentDictionary<TKey,TValue>. For some excellent information on the performance of the concurrent collections and how they perform compared to a traditional brute-force locking strategy, see this wonderful whitepaper by the Microsoft Parallel Computing Platform team here.   Tweet Technorati Tags: C#,.NET,Concurrent Collections,Collections,Multi-Threading,Little Wonders,BlackRabbitCoder,James Michael Hare

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  • What are the steps taken by this GLSL code?

    - by user827992
    1 void main(void) 2 { 3 vec2 pos = mod(gl_FragCoord.xy, vec2(50.0)) - vec2(25.0); 4 float dist_squared = dot(pos, pos); 5 6 gl_FragColor = (dist_squared < 400.0) 7 ? vec4(.90, .90, .90, 1.0) 8 : vec4(.20, .20, .40, 1.0); 9 } taken from http://people.freedesktop.org/~idr/OpenGL_tutorials/03-fragment-intro.html Now, this looks really trivial and simple, but my problem is with the mod function. This function is taking 2 vec2 as inputs but is supposed to take just 2 atomic arguments according to the official documentation, also this function makes an implicit use of the floor function that only accepts, again, 1 atomic argument. Can someone explain this to me step by step and point out what I'm not getting here? It's some kind of OpenGL trick? OpenGL Math trick? in the GLSL docs i always find and explicit reference to the type accepted by the function and vec2 it's not there.

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  • How to understand the memory usage and load average in linux server

    - by Tim
    Hi, I am using a linux server which has 128GB of memory and 24 cores. I use top to see how much it is used. Its output is pasted at the end of the post. Here are two questions: (1) I see that each of the running processes occupies a very small percentage of memory (%MEM no more than 0.2%, and most just 0.0%), but how the total memory is almost used as in the fourth line of output ("Mem: 130766620k total, 130161072k used, 605548k free, 919300k buffers")? The sum of used percentage of memory over all processes seems unlikely to achieve almost 100%, doesn't it? (2) how to understand the load average on the first line ("load average: 14.04, 14.02, 14.00")? Thanks and regards! Edit: Thanks! I also really like to hear some rough numbers based on used percentage of memory to determine if a server is heavily loaded, since I once became the one who cramed the server without understanding the current load. Is swap regarded as almost the same as memory? For example, when memory and swap are almost of same size, if the memory is almost running out but the swap is still largely free, may I just view it as if the used percentage of memory + swap is still not high and run other new processes? How would you consider together CPU or memory (or memory + swap) usage? Do you become worried if either of them reaches too high or both? Output of top: $ top top - 12:45:33 up 19 days, 23:11, 18 users, load average: 14.04, 14.02, 14.00 Tasks: 484 total, 12 running, 472 sleeping, 0 stopped, 0 zombie Cpu(s): 36.7%us, 19.7%sy, 0.0%ni, 43.6%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Mem: 130766620k total, 130161072k used, 605548k free, 919300k buffers Swap: 63111312k total, 500556k used, 62610756k free, 124437752k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 6529 sanchez 18 -2 1075m 219m 13m S 100 0.2 13760:23 MATLAB 13210 timothy 18 -2 48336 37m 1216 R 100 0.0 3:56.75 absurdity 13888 timothy 18 -2 48336 37m 1204 R 100 0.0 2:04.89 absurdity 14542 timothy 18 -2 48336 37m 1196 R 100 0.0 1:08.34 absurdity 14544 timothy 18 -2 2888 2076 400 R 100 0.0 1:06.14 gatherData 6183 sanchez 18 -2 1133m 195m 13m S 100 0.2 13676:04 MATLAB 6795 sanchez 18 -2 1079m 210m 13m S 100 0.2 13734:26 MATLAB 10178 timothy 18 -2 48336 37m 1204 R 100 0.0 11:33.93 absurdity 12438 timothy 18 -2 48336 37m 1216 R 100 0.0 5:38.17 absurdity 13661 timothy 18 -2 48336 37m 1216 R 100 0.0 2:44.13 absurdity 14098 timothy 18 -2 48336 37m 1204 R 100 0.0 1:58.31 absurdity 14335 timothy 18 -2 48336 37m 1196 R 100 0.0 1:08.93 absurdity 14765 timothy 18 -2 48336 37m 1196 R 99 0.0 0:32.57 absurdity 13445 timothy 18 -2 48336 37m 1216 R 99 0.0 3:01.37 absurdity 28990 root 20 0 0 0 0 S 2 0.0 65:50.21 pdflush 12141 tim 18 -2 19380 1660 1024 R 1 0.0 0:04.04 top 1240 root 15 -5 0 0 0 S 0 0.0 16:07.11 kjournald 9019 root 20 0 296m 4460 2616 S 0 0.0 82:19.51 kdm_greet 1 root 20 0 4028 728 592 S 0 0.0 0:03.11 init 2 root 15 -5 0 0 0 S 0 0.0 0:00.00 kthreadd 3 root RT -5 0 0 0 S 0 0.0 0:01.01 migration/0 4 root 15 -5 0 0 0 S 0 0.0 0:08.13 ksoftirqd/0 5 root RT -5 0 0 0 S 0 0.0 0:00.00 watchdog/0 6 root RT -5 0 0 0 S 0 0.0 17:27.31 migration/1 7 root 15 -5 0 0 0 S 0 0.0 0:01.21 ksoftirqd/1 8 root RT -5 0 0 0 S 0 0.0 0:00.00 watchdog/1 9 root RT -5 0 0 0 S 0 0.0 10:02.56 migration/2 10 root 15 -5 0 0 0 S 0 0.0 0:00.34 ksoftirqd/2 11 root RT -5 0 0 0 S 0 0.0 0:00.00 watchdog/2 12 root RT -5 0 0 0 S 0 0.0 4:29.53 migration/3 13 root 15 -5 0 0 0 S 0 0.0 0:00.34 ksoftirqd/3

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  • no entry for / in /etc/fstab

    - by valya
    Hello! I can't find an entry for mounting "/" in /etc/fstab (I was hoping to set commit value to something big because my HDD is pretty slow): [.../fest]$ cat /etc/fstab # UNCONFIGURED FSTAB FOR BASE SYSTEM /dev/sda3 /media/megahard ntfs-3g defaults,locale=en_US.UTF-8 0 0 /mnt/2Gb.swap none swap sw 0 0 [.../fest]$ cat /etc/issue Ubuntu 10.10 \n \l Netbook Remix, installed with chroot from Wubi (it's not Wubi, it's just installed from it)

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  • Gparted Partition Mount Points Alternate Between 2 Physical Disk Drives

    - by California Ken
    I'm running Ubuntu Server 14.04 on a system with 2 physical disk drives. I am frequently seeing mount errors on startup. When I check the drive partitions using GPARTED, I see that my two "non-system created" data partitions have the wrong disk assignments (i.e. sda1 vs sdb1) or visa-versa. If I hand edit /etc/fstab to match GPARTED, the system will boot error free one time. On the second restart I will get the "serious mount problem" error for the 2 data partitions and when I check GPARTED, the disk assignments have changed again (again, GPARTED and fstab don't match). A listing of my /etc/fstab is: /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). # / was on /dev/sdb2 during installation UUID=766a06a4-e5af-484a-adf0-fa1e88da7212 / ext4 errors=remount-ro,user_xattr,acl,barrier=1 0 1 swap was on /dev/sda6 during installation UUID=8c42f835-ead3-43fb-88d8-196f5dfc3aa7 none swap sw 0 0 swap was on /dev/sdb3 during installation UUID=2214deec-ba98-47da-aea7-4e46998f3e57 none swap sw 0 0 /dev/fd0 /media/floppy0 auto rw,user,noauto,exec,utf8 0 0 /dev/sda1 /media/ken/Linux-Data ext3 defaults 0 2 /dev/sda5 /media/ken/Data2 ext4 defaults 0 2 The device designations in the last 2 lines are the ones in question. The fstab entries to NOT change between system restarts but the mount points in the GPARTED display do. Does anyone have a fix for this? Thanks Mr. Young and Mr Gedak, Following is my fstab file and two blkid outputs. The fstab output is correct. The first blkid output was after a reboot and is WRONG! The sda and sdb device partition data is reversed. The 2nd blkid output was after a second reboot (fstab not changed). It shows the sda and adb partition data CORRECTLY. I didn't see any duplicate UUIDs. Does anyone have any idea why the GPARTED and blkid outputs alternate on consecutive reboots? The alternating partition data is real since when the partition assignments are reversed, the boot sequence halts with disk mounting errers (I have to press "s" to skip the mounts). Thanks again. Ken I copied the contents of a text file showing my fstab and 2 blkid outputs. The text file contents show up in the text entry box but does not appear in the main body of the question. Is there a way I can attach the text file or edit this question so that the text is displayed for question viewers?

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