This page provides the user with information on options available for repairing GRUB 2 boot issues and specific instructions on how to use the GRUB 2 terminal. The instructions are written for GRUB 1.99, which is the version of GRUB 2 which is included on Ubuntu 11.04, Natty Narwhal, and later. Differences for version 1.98 (Ubuntu 10.4, Lucid Lynx) are noted when the procedures differ.

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GRUB 2’s ability to fix boot problems is greatly improved over the original GRUB bootloader. In addition to an automatic fallback mode if booting from a menuentry in a submenu, GRUB 2 allows the user to edit its menu before the operating system is loaded. The rescue mode GRUB 2 terminal can help boot an operating system so that permanent repairs to system files can be made.

The instructions on this page are written for a fully-installed Ubuntu operating system. WUBI boot problems are not covered in detail although they are addressed in several sections.

Source: Grub2/Troubleshooting – Community Help Wiki

Use Boot Repair to fix your bootloader.

1. Boot Ubuntu from a LiveCD or Live USB
2. Connect to the internet
3. Open a terminal, and add the Boot Repair PPA

   sudo add-apt-repository ppa:yannubuntu/boot-repair && sudo apt-get update

4. Install Boot Repair

   sudo apt-get install -y boot-repair && boot-repair

5. Launch and use, see https://help.ubuntu.com/community/Boot-Repair#Using_Boot-Repair for more details

Source: grub2 – After update, get “error: file not found.” followed by “grub rescue> _” – Ask Ubuntu

 

i’m trying to install Ubuntu. I don’t know if it is important, but i’m trying to install it on external HDD. In the end i have external bootable HDD which only displays: error: file not found grub recovery> From the beginning: I’ve downloaded ubuntu-12.04-desktop-i386.iso I’ve used LiLi USB Creator (LinuxLive) to create bootable pendrive from that image I’ve bootet from it, it works I’ve clicked “Try ubuntu”, it works too. I’ve used GParted to look over drivers (disks) My primary embedded disk is seen as /dev/sda My attached external disk as /dev/sdb My PenDrive as /dev/sdc I’ve created partitions on /dev/sdb Fist partition for system (over 200GiB) Second was there already (it’s xsf, and i don’t want to touch it :P) Third is extended partition, with 1 locital partiton (10GiB) for swap I’ve started installation i’ve choose “somethin else” in … i belive secound screeb then is selected /dev/sdb as boot disk for first partiton of /dev/sdb i set i want ext3 file system, i’ve check “formattin” checkbox, and mount path set to “/” firs logical partiton set as swap partition After installation finished, i restarted my computer. When i boot from my primary disc it’s work ok, my previous operating system – vista – works ok. When i set my BIOS to boot from my external disc, i only get that message: error: file not found grub recovery> I’ve try to reinstall it, but didn’t help… In desperation, i’ve try to read a bit about that “grub recovery>” command-line and experiment a bit… I’m not sure if this has had any point, or if it give you some information (notice, that i don’t know what i’m doing 😛 ) when i’ve type command: insmod (hd1,1)/boot/grub/linux.mod i’ve get message: unknown filesystem the same with: insmod (hd1,msdos1)/boot/grub/linux.mod the same with: insmod ext3 but i get no message after command: insmod ext2 … notice that i really don’t know what this command exactly do, but than i thought that maybe if i reinstall ubuntu with ext2 filesystem, it will work. I’ve done that, but symptoms are the same. I’ve go back to that Live version of ubuntu, filesystem and basics directories seems to be present on /dev/sdb1 … i’m completely unfamiliar with GRUB. I’m also don’t know which wersion of GRUB it is, i hope there is only one version on ubuntu-12.04-desktop-i386.iso Any help? Thax ======================= edit 17.06.2012 22:05 ========================= This is RESULTS.txt from bootinfoscript sda is my in-build HDD sdb is external HDD (disk-destination for Ubuntu) sdc is PenDrive with Live Ubuntu Boot Info Script 0.61 [1 April 2012] ============================= Boot Info Summary: =============================== => Windows is installed in the MBR of /dev/sda. => 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 (,msdos1)/boot/grub on this drive. => Syslinux MBR (4.04 and higher) is installed in the MBR of /dev/sdc. sda1: __________________________________________________________________________ File system: vfat Boot sector type: Windows 7: FAT32 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 Vista Boot files: /bootmgr /Boot/BCD /Windows/System32/winload.exe sda3: __________________________________________________________________________ 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 63. Operating System: Boot files: sdb1: __________________________________________________________________________ File system: ext2 Boot sector type: - Boot sector info: Operating System: Ubuntu 12.04 LTS Boot files: /boot/grub/grub.cfg /etc/fstab /boot/grub/core.img sdb3: __________________________________________________________________________ File system: xfs Boot sector type: - Boot sector info: Mounting failed: mount: /dev/sdb3: can't read superblock sdb4: __________________________________________________________________________ File system: Extended Partition Boot sector type: - Boot sector info: sdb5: __________________________________________________________________________ File system: swap Boot sector type: - Boot sector info: sdc1: __________________________________________________________________________ File system: vfat Boot sector type: SYSLINUX 4.04 2011-04-18 Boot sector info: Syslinux looks at sector 3250552 of /dev/sdc1 for its second stage. SYSLINUX is installed in the directory. The integrity check of the ADV area failed. No errors found in the Boot Parameter Block. Operating System: Boot files: /syslinux/syslinux.cfg /ldlinux.sys ============================ Drive/Partition Info: ============================= Drive: sda _____________________________________________________________________ Disk /dev/sda: 160.0 GB, 160041885696 bytes 16 heads, 63 sectors/track, 310101 cylinders, total 312581808 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 20,482,047 20,480,000 1c Hidden W95 FAT32 (LBA) /dev/sda2 * 20,482,048 176,771,071 156,289,024 7 NTFS / exFAT / HPFS /dev/sda3 176,771,072 312,580,095 135,809,024 f W95 Extended (LBA) /dev/sda5 176,773,120 312,580,095 135,806,976 7 NTFS / exFAT / HPFS Drive: sdb _____________________________________________________________________ Disk /dev/sdb: 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 Partition Boot Start Sector End Sector # of Sectors Id System /dev/sdb1 * 2,048 574,773,569 574,771,522 83 Linux /dev/sdb3 574,773,570 1,208,315,584 633,542,015 7 NTFS / exFAT / HPFS /dev/sdb4 1,208,317,950 1,229,289,471 20,971,522 f W95 Extended (LBA) /dev/sdb5 1,208,317,952 1,229,289,471 20,971,520 82 Linux swap / Solaris Drive: sdc _____________________________________________________________________ Disk /dev/sdc: 1971 MB, 1971322880 bytes 129 heads, 40 sectors/track, 746 cylinders, total 3850240 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 * 40 3,850,239 3,850,200 6 FAT16 "blkid" output: ________________________________________________________________ Device UUID TYPE LABEL /dev/loop0 squashfs /dev/loop1 7aa47a24-93a0-d54f-a03c-495cf2ee0927 ext2 /dev/sda1 3C98-AC5D vfat RECOVERY /dev/sda2 94CA2D3CCA2D1BCC ntfs VistaOS /dev/sda5 A2F09F72F09F4B83 ntfs DATA /dev/sdb1 a4befd4a-f91f-4f09-9d5f-a44991ed6a2e ext2 /dev/sdb3 973a36d7-5828-4291-b455-db286cd69668 xfs /dev/sdb5 9ce43dea-fd93-4343-969d-1243397724bd swap /dev/sdc1 7232-C522 vfat GOODDRIVE ================================ Mount points: ================================= Device Mount_Point Type Options /dev/loop0 /rofs squashfs (ro,noatime) /dev/sdc1 /cdrom vfat (rw,relatime,fmask=0022,dmask=0022,codepage=cp437,iocharset=iso8859-1,shortname=mixed,errors=remount-ro) =========================== sdb1/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 "${boot_once}" ]; then save_env recordfail; fi; fi } function load_video { insmod vbe insmod vga insmod video_bochs insmod video_cirrus } insmod part_msdos insmod ext2 set root='(hd1,msdos1)' search --no-floppy --fs-uuid --set=root a4befd4a-f91f-4f09-9d5f-a44991ed6a2e if loadfont /usr/share/grub/unicode.pf2 ; then set gfxmode=auto load_video insmod gfxterm insmod part_msdos insmod ext2 set root='(hd1,msdos1)' search --no-floppy --fs-uuid --set=root a4befd4a-f91f-4f09-9d5f-a44991ed6a2e set locale_dir=($root)/boot/grub/locale set lang=pl_PL 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, za pomocą systemu Linux 3.2.0-23-generic-pae' --class ubuntu --class gnu-linux --class gnu --class os { recordfail gfxmode $linux_gfx_mode insmod gzio insmod part_msdos insmod ext2 set root='(hd1,msdos1)' search --no-floppy --fs-uuid --set=root a4befd4a-f91f-4f09-9d5f-a44991ed6a2e linux /boot/vmlinuz-3.2.0-23-generic-pae root=/dev/sdb1 ro quiet splash $vt_handoff initrd /boot/initrd.img-3.2.0-23-generic-pae } menuentry 'Ubuntu, za pomocą systemu Linux 3.2.0-23-generic-pae (tryb ratunkowy)' --class ubuntu --class gnu-linux --class gnu --class os { recordfail insmod gzio insmod part_msdos insmod ext2 set root='(hd1,msdos1)' search --no-floppy --fs-uuid --set=root a4befd4a-f91f-4f09-9d5f-a44991ed6a2e echo 'Wczytywanie systemu Linux 3.2.0-23-generic-pae...' linux /boot/vmlinuz-3.2.0-23-generic-pae root=/dev/sdb1 ro recovery nomodeset echo 'Wczytywanie początkowego dysku RAM...' initrd /boot/initrd.img-3.2.0-23-generic-pae } ### 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='(hd1,msdos1)' search --no-floppy --fs-uuid --set=root a4befd4a-f91f-4f09-9d5f-a44991ed6a2e linux16 /boot/memtest86+.bin } menuentry "Memory test (memtest86+, serial console 115200)" { insmod part_msdos insmod ext2 set root='(hd1,msdos1)' search --no-floppy --fs-uuid --set=root a4befd4a-f91f-4f09-9d5f-a44991ed6a2e linux16 /boot/memtest86+.bin console=ttyS0,115200n8 } ### END /etc/grub.d/20_memtest86+ ### ### BEGIN /etc/grub.d/30_os-prober ### menuentry "Windows Recovery Environment (loader) (on /dev/sda1)" --class windows --class os { insmod part_msdos insmod fat set root='(hd0,msdos1)' search --no-floppy --fs-uuid --set=root 3C98-AC5D drivemap -s (hd0) ${root} chainloader +1 } menuentry "Windows Vista (loader) (on /dev/sda2)" --class windows --class os { insmod part_msdos insmod ntfs set root='(hd0,msdos2)' search --no-floppy --fs-uuid --set=root 94CA2D3CCA2D1BCC 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 ### -------------------------------------------------------------------------------- =============================== sdb1/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/sdb1 during installation UUID=a4befd4a-f91f-4f09-9d5f-a44991ed6a2e / ext2 errors=remount-ro 0 1 # swap was on /dev/sdb5 during installation UUID=9ce43dea-fd93-4343-969d-1243397724bd none swap sw 0 0 -------------------------------------------------------------------------------- =================== sdb1: Location of files loaded by Grub: ==================== GiB - GB File Fragment(s) = boot/grub/core.img 1 = boot/grub/grub.cfg 1 = boot/initrd.img-3.2.0-23-generic-pae 6 = boot/vmlinuz-3.2.0-23-generic-pae 3 = initrd.img 6 = vmlinuz 3 ========================= sdc1/syslinux/syslinux.cfg: ========================== -------------------------------------------------------------------------------- # D-I config version 2.0 include menu.cfg default vesamenu.c32 prompt 0 timeout 50 ui gfxboot bootlogo -------------------------------------------------------------------------------- ================= sdc1: Location of files loaded by Syslinux: ================== GiB - GB File Fragment(s) ?? = ?? ldlinux.sys 1 ?? = ?? syslinux/chain.c32 1 ?? = ?? syslinux/gfxboot.c32 1 ?? = ?? syslinux/syslinux.cfg 1 ?? = ?? syslinux/vesamenu.c32 1 ============== sdc1: Version of COM32(R) files used by Syslinux: =============== syslinux/chain.c32 : COM32R module (v4.xx) syslinux/gfxboot.c32 : COM32R module (v4.xx) syslinux/vesamenu.c32 : COM32R module (v4.xx) =============================== StdErr Messages: =============================== 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 /home/ubuntu/Pobrane/bootinfoscript-061/bootinfoscript: line 1646: [: 2.73495e+09: integer expression expected I have to say that script print on terminal: Boot Info Script 0.61 [1 April 2012] "gawk" could not be found, using "busybox awk" instead. This may lead to unreliable results. Identifying MBRs... Computing Partition Table of /dev/sda... Computing Partition Table of /dev/sdb... Computing Partition Table of /dev/sdc... Searching sda1 for information... Searching sda2 for information... Searching sda3 for information... Searching sda5 for information... Searching sdb1 for information... Searching sdb3 for information... Searching sdb4 for information... Searching sdb5 for information... Searching sdc1 for information... Finished. The results are in the file "RESULTS.txt" located in "/home/ubuntu/Pobrane/bootinfoscript-061/". ============== edit 18.06.2012 18:38 =============== ok, this is more or less copy of my grub recovery session: error: file not found grub recovery> set prefix=(hd0,msdos1)/boot/grub root=hd0,msdos1 grub recovery> ls (hd0) (hd0,msdos3) (hd0,msdos1) (hd1) (hd1,msdos5) (hd1,msdos2) (hd1,msdos1) grub recovery> ls $prefix error: file not found grub recovery> then i’ve used ‘ls’ cmd on few path, results are strange (i think): grub recovery> ls (hd0,msdos1)/boot grub recovery> ls (hd0,msdos1)/boot/grub error: file not found grub recovery> ls (hd0,msdos1)/lib grub recovery> ls (hd0,msdos1)/bin grub recovery> ls (hd0,msdos1)/sys ./ ../ grub recovery> ls (hd0,msdos1)/sbin grub recovery> ls (hd0,msdos1)/usr ./ ../ local/ (and some other things) is this normal? i can see /boot/grub and its content when i mount this external HDD by Live Ubuntu 12.04 installation grub2 shareimprove this question edited Jun 18 ’12 at 16:54 asked Jun 17 ’12 at 13:53 Tomasz Grabowski 33114

At the grub rescue shell, could you run “set” (which will print all environment variables) and post what the exact value of $prefix is? Could you also run “ls”, and “ls $prefix” and post the output of both? (if it’s too much work to copy it down exactly, taking a picture with a camera and posting that works too). – Jordan Uggla Jun 17 ’12 at 21:29 add a comment

3 Answers

activeoldestvotes

up vote3down voteaccepted

The symptom of being able to see some files but not all on a filesystem with grub usually means that your BIOS is buggy and can’t properly handle large drives ( http://tldp.org/HOWTO/Large-Disk-HOWTO-4.html ). What happens is that the BIOS can’t read blocks past a certain point in the drive, and so if your root filesystem starts before that limit, but ends after that limit, then some files will be accessible at boot through the BIOS and others won’t. The standard way to work around this problem is to create a small /boot/ partition near the beginning of the drive, to ensure that everything that needs to be read through the BIOS, can be. I would normally expect “out of disk” errors from grub were this the case, and I don’t know why we’re not seeing those. One way to confirm that the problem is a BIOS limit is to go into your BIOS menus and see what size it lists the drive as being, if it lists it as being less that the actual size, you know your BIOS is buggy. Another way, if your BIOS doesn’t list sizes anywhere in its menus, is to run “ls -l” from grub and look at the size listed there. Unfortunately, you can’t run “ls -l” from the rescue shell, so you’d need to boot from a grub CD, or have already fixed the problem with a small /boot/ partition, before you could do the check from within grub. shareimprove this answer edited Jan 24 ’14 at 3:22 answered Jun 18 ’12 at 19:30 Jordan Uggla 2,6131015

This is the solution. Thank you for your knowledge and time. Now i’m happy user of Ubuntu 😛 – Tomasz Grabowski Jun 19 ’12 at 21:40 You’re welcome 🙂 – Jordan Uggla Jun 19 ’12 at 23:59 add a comment

up vote1down vote

Change your booting preferences to boot from the external hard disk. The computer is trying to find grub on your in- built HDD but its actually in the external HDD. So you will have to change your booting options to use that external HDD for booting as the first preference and then the in – built HDD the second preference. So if your insert your external HDD then it will automatically boot ubuntu and if you don’t then it will boot up the system that you have installed it in the in – built HDD. shareimprove this answer answered Jun 17 ’12 at 14:20 Pranit Bauva 6761822

Do you mean to set in BIOS to boot from external HDD? I don’t think so. It’s done. What more important: I said that when i boot from in-build HDD it’s start normally (so i think GRUB is not installed there) and when i change it to boot from external HDD, than i get message from GRUB, so GRUB seems to be present on my external disk, but somehow can not work properly. – Tomasz Grabowski Jun 17 ’12 at 14:30 add a comment

up vote1down vote

If your still having issues with this try the “GRUB Customizer” sudo apt-get grub-customizer PLUG IN YOUR PENDRIVE or external USB start it from the gui Administrator tools Admin->grub-Customizer or Q! After it starts it will read your boot script similar to bootinfoscript so wait a few seconds for it to finish then the boot information window will change color from grey to normal. You can then edit the boot information for each drive as it was found. to Add a new entry just press edit->Add then select Linux. using the tab button verify that the disk UUID matches the disk you want to boot from. click finish. click save button verify your edits manual view the grub-boot menu to ensure edits were saved. I am assuming your grub boot loader is on hd0 or sda0. cat out /hd0/boot/grub/grub.cfg # don’t edit this file just view or verify it. or run your bootinfoscript again. if this doesn’t fix the problem then you could be having issues with the kernel. I had to reinstall my Ubuntu-LTS this way because another Linux 64bit install diddled with the boot loader too much. If your using a 64bit machine then verify that the usb-drive /pendrive is also 64-bit OS. Otherwise the USB driver will fork when it tries to load the USB drive. It was a good idea that the new OS be kept small about 6-10MB so you don’t hit the upper bound limits on Large GB-HDs. You also need to verify that any external USB drivers are installed before grub runs. To do this press the down-arrow key on the purple screen to see what modules are being installed and which ones fork. If this didn’t help you try using a rescue disk to pick up the missing kernel/files. I use bootrecovery-CD (sourceforge:boot-repair-diskx64) or Linux-remix-CD (www.ubuntu-rescue-remix.org) when things go wrong with Grub-Customizer. shareimprove this answer

Source: installation – How to fix ‘grub error file not found’ when installing 12.04? – Ask Ubuntu

Elektor is a monthly magazine about all aspects of electronics, first published as Elektuur in the Netherlands in 1960, and now published worldwide in many languages including English, German, Dutch, French, Greek, Spanish, Swedish, Portuguese (European and Brazilian) and Italian with distribution in over 50 countries. The English language edition of Elektor was launched in 1975 and is read worldwide.

Elektor publishes a vast range of electronic projects, background articles and designs aimed at engineers, enthusiasts, students and professionals. To help readers build featured projects, Elektor also offer PCBs (printed circuit boards) of many of their designs, as well as kits and modules. If the project employs a microcontroller and/or PC software, as is now often the case, Elektor normally supply the source code and files free of charge via their website. Most PCB artwork is also available from their website.

Elektor also publish books, CDs and DVDs about audio, microprocessors, software, programming languages and general purpose electronics.

Elektor is published by Elektor International media, headquartered in Limbricht, The Netherlands.

In December 2009 Elektor announced that for the American market a strategic cooperation would be entered with Steve Ciarcia‘s Circuit Cellar magazine ^[1][2]

It also features articles about vintage electronics e.g. from the 1960s called retronics.

The English edition of Elektor is distributed in North America (USA and Canada) with ISSN 1947-3753 and in the UK and elsewhere with ISSN 1757-0875.

Source: Elektor – Wikipedia

Steve Ciarcia is an embedded control systems engineer. He became popular through his Ciarcia’s Circuit Cellar column in BYTE magazine, and later through the Circuit Cellar magazine that he published. He is also the author of Build Your Own Z80 Computer, edited in 1981 and Take My Computer…Please!, published in 1978. He has also compiled seven volumes of his hardware project articles that appeared in BYTE magazine.

In 1982 and 1983 he published a series of articles on building the MPX-16, a 16-bit single-board computer that was hardware-compatible with the IBM PC.^[1][2][3]

In December 2009, Steve Ciarcia announced that for the American market a strategic cooperation would be entered between Elektor and his Circuit Cellar magazine.^[4] In November 2012, Steve Ciarcia announced that he is quitting Circuit Cellar and Elektor would take it over.^[5]

In October, 2014, Ciarcia purchased Circuit Cellar, audioXpress, Voice Coil, Loudspeaker Industry Sourcebook, and their respective websites, newsletters, and products from Netherlands-based Elektor International Media. The aforementioned magazines will continue to be published by Ciarcia’s US-based team.

Source: Steve Ciarcia – Wikipedia

Free online library on electronics. All issues of Circuit Cellar mazagine and more

Source: Download Circuit Cellar 2014 archive free

HOWTO: Repair a broken Ext4 Superblock in Ubuntu

31mar10

This has happened to me a few times, and it’s not a nice problem to find yourself in. You computer won’t boot, all your filesystem checks tell you you’ve a bad superblock, but you cant seem to find how to fix it. Well, here goes

This guide is for ext4 , though I’ll explain how other filesystems can be cured along the way. The easiest way to carry all this out, seeing as your computer probably won’t boot at this stage, is to download and burn a copy of Parted Magic. Boot from that, and you’ll access to a number of useful tools.

First, figure out what partition we’re dealing with.

1	sudo fdisk -l

The above will list all the partitions on all the drives in your computer. To recover a lost partition, your going to need Testdisk. Testdisk is included in Parted Magic, and there’s a great guide on their site. For this though, we just need the partition number, such as /dev/sda3 or /dev/hdb1.

Now, make sure your superblock is the problem, by starting a filesystem check, replacing xxx with your partition name. Here, you can change ext4 to ext3, or ext2 to suit the filesystem.

1	sudo fsck.ext4 -v /dev/xxx

If your superblock is corrupt, the output will look like this

Source: HOWTO: Repair a broken Ext4 Superblock in Ubuntu | Linux Expresso

I have php file that contains variables:$t1 = $_POST[‘t1’];$t2 = $_POST[‘t2’];and I need to pass these variables into the respective html form fields:form is located in different page than php file with variables. it’s url is “form.php”I guess I need to create php post command in my php file that redirects to url “form.php” and loads $t1 and $t2 into respective form fields “field_1” and “field_2”?Trying around but can not find right solution..Any ideas appreciated Brgds, Raivis

Source: php pass data to html form – Stack Overflow

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Source: html – How to call a JavaScript function, declared in , in the body when I want to call it – Stack Overflow

Source: XML DOM – HttpRequest object

I’m trying to post data to a PHP page and check the response. Here is an example. What is wrong with this code?index.html

Source: php – POST from XMLHttp with parameters – Stack Overflow

How can I SELECT the last row in a MySQL table?I’m INSERTing data and I need to retrieve a column value from the previous row.There’s an auto_increment in the table.

Source: Select last row in MySQL – Stack Overflow