General :: What's A File System's "magic" Number In A Super Block

Jan 28, 2011

I'm working on a midrange NAS system basically running on Linux and I got to do some great testing today. The step-by-step lead me to using fsdb to corrupt the magic number on a file system in order to corrupt it / test the script that should fix it.

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Hardware :: Always Getting Bad Magic Number In Super-block?

Jul 1, 2010

I've been setting up a number of netbooks for friends in a group I belong to. I am installing Ubuntu 10.04 and/or Linux Mint 9 on all of the netbooks. The netbooks are all identical. Everything has seemed OK until yesterday. I tried to set the label on the new disk using: # e2label /dev/sda newlabel The error is Bad magic number in super-block while trying to open /dev/sda. Couldn't find valid filesystem superblock.

But the filesystem seems fine. It is mounted. It booted up without errors. But all the e2* tools give the same error. So I checked another netbook with an identical fresh install of Ubuntu 10.04 32-bit. It gives the same error although the system appears to work fine. Next I went and checked my own netbook. It is identical except I swapped out the HDD for an OCZ Vertex SSD. I aligned the partitions and prepared that drive carefully. It seems to work great. But when I ran e2label on it I got the same error message.

All the other installs are fresh, clean, standard installs where I let the installer use the whole disk and do the partitioning automatically. All are using ext4. I did a fresh install of Linux Mint 9 and it has the same error as Ubuntu 10.04. Kubuntu 10.04 on my desktop gives the same error too.

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Red Hat :: File System Corruption - Super Block Could Not Be Read Or Don't Describe A Clear Ext2 File System

Jul 12, 2010

My Redhat Enterprise Linux 4 with 6x partitions (/, /boot,/home, /usr, /var, /tmp) of 6.0 GB IDE Hardisk was working quite fine. I decided to create LVM on /home and /var partitions but due to some errors occured and I delete the /home partitions. That's why partition table altered. I then delete 4,5,and 6th partitions (/home, /var, /tmp) partitions and now try to create one by one but following error is coming:-


The Super block could not be read or do not describe a clear ext2 file system. E2fsck b 8193 <device> I have tried following commands,but could not successful:- e2fsck -p /dev/hda7 (where hda7 was created but afterthat it was deleted) e2fsck -a /dev/hda7

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Programming :: Algorithm - File System Block Number For Immediate Read

May 20, 2010

input: file system block number for immediate read
file system block number for asynchronous read
output:buffer containing data for immediate read {
if(first block not in cache) {
get buffer for first block
if(buffer data not valid)
initiate disk read }
if(second block not in cache) {
get buffer for second block)
if(buffer data valid) //line 1
release buffer else
initiate disk read //line 2 }
if(first block was originally in cache) //line 3 {
read first block
return buffer }
sleep (event first buffer contains valid data)
return buffer }

Here is an algorithm for block read algorithm. I have problem in
line 1: If buffer data is valid why is it releasing the buffer?
line 2: If buffer data valid why is it initiating disk read. It should have read directly from buffer?
line 3: It should be the first condition as if it is there in cache then it should return it without delay?

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General :: File System, Parted Magic?

Mar 29, 2011

What file system choices do I have for fedora 14, what is suggested and can parted magic provide that system?I am loading fedora on the second hard drive of my laptop with windows 7 and XP pro on the other hard drive and I will also be repartitioning and reformating the first hard drive because windows 7 is 64 bit and the xp is 32.

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General :: Hard Drive - Get Block Number / Position Of File On HDD?

Feb 28, 2010

How can I retrieve the block number(s) of a certain file in a file system (the blocks the file is using on the harddisc)?

I'm using the gentoo linux based SystemRescueCD, so I got plenty of tools installed which might get that information for me.

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General :: Adding A Kernel In GRUB For Kubuntu 9.10: Invalid Magic Number

Apr 19, 2010

I've compiled and added a kernel in Gentoo before. It doesn't seem to go quite as smoothly in Kubuntu 9.10 These are the steps I followed: I unpacked the kernel in /usr/src and ran make && make modules_install succesfully. Then I copied the kernel in arch/x86/boot/bzImage to /boot/bzImage-2.6.32 This entry is the one given by Kubuntu:


menuentry "Ubuntu, Linux 2.6.31-14-generic" {
if [ -n ${have_grubenv} ]; then save_env recordfail; fi
set quiet=1


I just read the script that update grub uses. Changed the name of the kernel from xyz to vmlinuz-2.6.32-generic and it worked.

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Software :: Know Name Of File Which Owns A Block Number On FS?

Apr 24, 2010

I need to monitor file reads&writes by all the apps. I have found a kernel feature /proc/sys/vm/block_dump. But it only gives me block numbers while i would like to know file names. How can i convert these block numbers to file names (if the blocks belong to a file, of course)?

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General :: Remove A File On System Using Inode Number?

May 19, 2010

If you create a file on UNIX/linux with special chars, like touch "la*, you can't remove it with rm "la*. You have to use the inode number(you can if you add the before the name, I know, but you'd have to guess as a user that it was used in the file creation).

I checked the manpage for rm, but there's no metion of the inode number. Doing rm inodenumber doesn't work either.

What is the command for this?

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General :: Fatal: Bad Magic Number In Executable `prime' (not An Executable?)

Sep 3, 2010

I am trying to run Wattch simulator in linux.But it is giving the error below. what is this error and what do I do about it?

fatal: bad magic number in executable `prime' (not an executable?)

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Debian :: 'INVALID Magic Number' - Grub2

May 6, 2011

I get error 'invalid magic number' when using this

vmlinuz 2,417,247 bytes

if I use this:

vmlinuz 2,417,312 bytes

then later it complains about kernel mismatch

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General :: "Bad Magic Number" - Error

Mar 2, 2010

I loaded all required files inside the Innovate ARM board.When It starts booting from that location it is showing a error "Bad magic number" How I can get out of this error.

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General :: Ifconfig Indicates Different Interrupt Number For Eth0 Than Proc Aqd Sys File System

Sep 22, 2011

On my system (OpenSUSE 11.4 - kernel 2.6.37) ifconfig indicates different interrupt number for eth0 than proc aqd sys file system.

ifconfig indicates 17:

proc fs indicates 43:

sys fs indicates 43:

Relevant part of lspci -vv output for irq 17 (this belongs to wlan0 and not to eth0):

Relevant part of lspci -vv output for irq 43:

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Ubuntu Installation :: Reboot After Update - Invalid Magic Number Error

Jan 7, 2010

This has to be the sixth time I am going to have to reinstall Ubuntu (Can't get enough of that Linux greatness) in the past 6 months. I just don't understand what exactly is wrong, I don't install anything extra (but the ubuntu restricted extras) yet updates that ask me to reboot will take me to a GRUB command line screen and trying to boot through the command line interface gives me an, "Invalid Magic Number", error.

There should be an official tool for when problems like this come up, so that users like me can easily move their files off their HDD before reinstalling. I didn't come here to rant but, does anyone know what may be causing this everytime, how it can be avoided maybe even how to deal with the Magic Number error and boot in (I wouldn't mind typing in the commands every time BTW)?

My system
Hp Compaq 6730s
2.0Ghz 575 Celeron
Intel X4500MHD
Broadcom 802.11b/g

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Hardware :: Installing New RAID Card Causes Existing Arrays To Have Bad Magic Number

May 13, 2010

I have two SAS RAID controller cards in a Dell server in slots 2 & 3, both with an array hanging off them. I went to install a third card into slot 1, but then when it boots it says two of my sd's have bad magic number in the super-block and it wants me to create an alternative one, which I don't want to do. If i remove the new card, the server boots perfectly like it did before I added the new card. Is the new card trying to control stuff that isn't hooked up to it because its in slot 1, so its confusing RHEL?

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Ubuntu :: Unity Launcher Number Shortcuts Have Disappeared While Holding Super In Natty

May 10, 2011

I've just noticed this morning that the number shortcuts that normally appear when holding the super key to show the Unity launcher are not there. The s, a and f shortcuts remain however. Also, just pushing the numbers that should be there doesn't do anything.

I've just upgraded from Maverick to Natty and things were mostly working fine until this. I'm not sure what changes have happened between now and then and I don't remember any major changes in that period.

I just tried to take a screenshot and opened GIMP to save it and I checked again and they have reappeared. So, I guess the new question is why did this happen? How can I solve this problem if it happens in the future? Should I mark this as solved? I don't really understand what happened either way.

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OpenSUSE Install :: Error Message Was 'bad Magic Number, Corrupt Superblock' With A Suggested Command To Try Another Superblock?

May 14, 2011

After several crashes during videos it seemed like a good idea to fsck root. Downloaded the latest systemrescuecd and ran it at boot. The error message was 'bad magic number, corrupt superblock' with a suggested command to try another superblock. That failed with the same message. Tried tune2fs to force fsck at boot and got the same message. The drive is less than 6 months old and the installed system is working more or less ok. The command I used was 'fsck.ext4 /dev/sdc2'. What am I doing wrong?

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Ubuntu Installation :: Dual Boot 10.04 LTS And CentOS 5.5 - Error "invalid Magic Number"

Oct 3, 2010

i wanted to see the red hat side of things and do some virtualization with CentOS, so i am trying to dual boot ubuntu 10.04 LTS and CentOS 5.5. the machine is a laptop, toshiba A100 series. what I did was to create the following partitioning scheme via Ubuntu LiveCd

Device Boot Start End Blocks Id System
/dev/sda1 * 1 19457 156288290+ 5 Extended
/dev/sda5 1 2103 16892284+ 83 Linux
/dev/sda6 2104 9988 63336231 83 Linux
/dev/sda7 9995 12623 21117411 83 Linux
/dev/sda8 12624 18800 49616721 83 Linux
/dev/sda9 18801 19457 5277321 82 Linux swap / Solaris

created an extended partition and in there have made sda5 and sda6 as / and home for ubuntu and sda7 and sda8 as / and home for CentOS. and sda9 as swap. I installed ubuntu first and then installed CentOS with no bootloader. Run sudo update-grub through ubuntu and now i have both Ubuntu and CentOS available. But when i select CentOS, i have an error which reads "invalid magic number".

I have grub2 installed, haven't downgraded or done anything to it and the ubuntu install is fresh, one week since i updated to 10.04 from scratch. I have found much contradictory stuff on google, but not something that provides a definite solution and also this post but the second command provided in the solution is one i cannot understand very well and it doesn't seem to work. what I am doing wrong here and how to make this work. I would prefer to do things via Ubuntu since debian stuff is what i am comfortable with and i am installing CentOS to learn not to do work on it.

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Ubuntu Installation :: 10.10 Wubi Upgrade Seems To Have Corrupted Bash / Error "invalid Magic Number"?

Jan 4, 2011

I tried the steps usually offered (modifying the grub.cfg file, replacing the wubildr files), it still wouldn't boot.

I booted in with the LiveCD to try to chroot into the environment and try running 'update-grub'. However, whenever I tried to chroot, it said it could not execute /bin/bash!

Trying to modify the grub commands manually (which originally gave the error: you need to load the kernal first), in the end said "invalid magic number"

There are some configuration things set in this installation I would like to not lose. Is it hopeless?

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Ubuntu Installation :: Burning A Number Of ISO's Of 101.10 And 11.04 To DVD - Unable To Find A Medium Containing A Live File System

Apr 27, 2011

I have tried burning a number of ISO's of 101.10 and 11.04 to DVD and intalling them on 2 of my desktop machines. I eventually see: ('initramfs) Unable to find a medium containing a live file system' The thought just occurred to me as I type this, perhaps I can only install from a CD and not a DVD?

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General :: Overwriting The Middle Of A File From A Block Device *without* Truncating File?

Jan 15, 2010

I have a Linux (Kubuntu) system with a large (~20Gb) file which I would like to mess with. Specifically, I want to copy the entire contents of another large file (~12Gb) to the middle of this file, and keep the bits of the file which are not overwritten.This is what I want to happen, with the text between the pipes representing file contents:Before:

outfile: |abcdefghijklmnopqrstuvwxyz|
infile: |123456789|


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General :: Script To Insert Number Of Lines In A File To The Start Of The File?

Sep 17, 2009

I'm looking for a way to insert the number of lines in a file to the start of the aformentioned file. This should be simple but as I am not used to scripts in Linux, I am finding it tough going. I can find the number of lines in a file easily enough via

filesize=$(awk 'END {print NR}' $1)

but as for inserting this into the first line, i'm failing to do so. I've tried some of the other approaches on these forums but none so far have been able to do so.

I've tried:

sed '1i$filesize' $1

but sed i requires a string, not a variable so no go I've also tried:

mv "$1" "${1}.bak" 2>/dev/null || touch "${1}.bak"
cat $filesize "${1}.bak" >"$1"

but again with no luck as cat seems to need an input stream Just to recap, i want to insert a line at the start of a given file that holds the number of lines the original file has.

ie the file:


should become:



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Security :: Ssh - Sshd Parameter To Set To Block Out User After Number Of Attempts Tp Login?

Apr 28, 2011

Is there an ssh or sshd parameter that can be set to block out a user after a set number of attempts tp login ?

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Ubuntu Networking :: Program \ Use To Monitor The Number Of Computers That Are Connected To Network And Block Them?

Feb 1, 2011

i have recently had a house mate move in and he is using my wireless network, even though i asked him not to give out the network key to his friends either he has or they have hacked my network and are using it when they come over, is there a program i can use to monitor the number of computers that are connected to my network and block them, or is there a way i can just wee what is going on. They seem to just connect and i don't want to have to change the password particularly because that involves changing it on multiple devices.

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Software :: Desktop System Monitor On Parted Magic Live CD?

Aug 16, 2010

what is the name of the Desktop System Monitor applet found on Parted Magic Live CD ?

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Ubuntu :: Buttons References - Use The <Super>ButtonX (<Super>Button1 For The Enabled Compiz Screenshot Plugin)?

Jun 5, 2011

how to use the <Super>ButtonX (<Super>Button1 for example for the enabled Compiz Screenshot plugin)? I also notice there is configurable buttons 1 throught 20 under the various options. At first I thought the ButtonX was a mouse button. Maybe it is with some anticipation of there being eventually being a possible 20 buttons on the mouse. I know the Super key is the Key with the Windows logo on it. But I don't know what to do to get the needed Super Key / Button combination. After having enabled Compiz's Screenshot plugin by its default, I don't get an image after hitting any of the Super key and mouse button combinations. I'm running Ubuntu 11.04.

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Red Hat / Fedora :: Magic Set Editor - No File Type Associated

May 25, 2009

I am having trouble getting a certain program to work. It's called Magic Set Editor and it has a linux version. It seems to install fine, but when I press the link to run the program it always says there is no file type associated with this program. Here is the site to download it: [URL]. I've tried the full and reduced versions, and I tried building it from source, which I have no idea how to do. I am using Fedora 10. Also, I've gone to their linux guy and he tried to help, but has never used Fedora, and so nothing he said worked.

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General :: Root User Account Number For System?

Feb 18, 2010

What is the user account number when you create a root user account for the system during the installation of any linux distribution? I'm not sure if its 0, 1, 10, or 100..

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General :: Memorize The System IRQs Number Columns 0-15?

Mar 20, 2011

I'M working my way through Trainsignal's CompTIA Linux + Training course and I have a question about IRQs. According to the lesson using the command "cat /proc/interrupts", I need to memorize the system IRQs number columns 0-15. But when I use this command, I get somewhat of an unordered list, see below.

Code: cat /proc/interrupts
0: 48 7 IO-APIC-edge timer
1: 247 205 IO-APIC-edge i8042


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General :: Max Number From The Name Of A File?

Mar 24, 2010

I need to get the max number from the name of a file

Formant of the file name:
Delimiter as underscore '_'


known part in the above file name will be GA.log A give directory may or may not contain files in the above format or may contain file other then the above format if so then ignore it.


1) Directory=/tmp/log having below listed files

ant_01_EG.log ant_02_GA.log ant_04_EG.log cvs_01_EG.log cvs_02_GA.log cvs_04_EG.log master_01_GA.log master_03_EG.log master_04_GA.log


output=> 06

2) Directory=/tmp/log no files

cmd=> ls *[0-9][0-9]_GA.log 2> /dev/null | awk -F_ '{ print $2}' | sort -nr | head -n1 | awk 'BEGIN { if ($1 >0 ) x=0; else x=1 } END {printf "%02.0f
", $1+1}'

output=> 01

if there are no files the output should be 01 and if file(s) found the output should be next highest number+1, In the above example it is 06 My cmd is bit lenghty. reduce my cmd and it should be in one line.

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