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System Administration 2

Admin FAQ

1. How can I have my script run every 30 minutes ?
2. How do I backup my partition table ?
3. How do I make a custom bootable CD ?
1.

How can I have my script run every 30 minutes ?

Cron is your best bet. Edit your crontab and add a line like this:

0,30 * * * *    /path/to/script
	    

 # run the job "my_script" every 30 minutes:
 */30 * * * * $HOME/bin/my_script
	    

For more info, use man 5 crontab".

2.

How do I backup my partition table ?

Applies to Any SuSE version

Even if you don't have a dualboot, do yourself a favor and backup your partition table. Just do this:

	  
 fdisk -l /dev/hda  >>mytable.txt 

(or whatever disks you have) and write it to a floppy or handcopy it to a piece of paper.

3.

How do I make a custom bootable CD ?

It is simple then to make a bootable CD. First create a file, say boot.img which is an exact image of the boot floppy currently in use. There is at least one HOWTO on making bootable floppies. If you have a bootable floppy handy, you can make a boot image with the command


dd if=/dev/fd0 of=boot.img bs=10k count=144

assuming the floppy is in the A: drive.

Place this image somewhere in the hierarchy which will be the source for the iso9660 filesystem. It is a good idea to put all boot related files in their own directory (boot/ under the root of the iso9660 fs, for example), but this is not necessary.

One caveat - Your boot floppy MUST load any initial ramdisk via LILO, not the kernel ramdisk driver! This is because once the linux kernel starts up, the BIOS emulation of the CD as a floppy disk is circumvented and will fail miserably. LILO will load the initial ramdisk using BIOS disk calls, so the emulation works as designed.

The El Torito specification requires a boot catalog to be created as well. This is a 2048 byte file which is of no interest except it is required. My patches to mkisofs will cause it to automatically create the boot catalog. You must specify where the boot catalog will go in the iso9660 filesystem. Usually it is a good idea to put it the same place as the boot image, and a name like boot.catalog seems appropriate.

So we have our boot image in the file boot.image, and we are going to put it in the directory boot/ under the root of the iso9660 filesystem. We will have the boot catalog go in the same directory with the name boot.catalog. The command to create the iso9660 fs in the file bootcd.iso is then


mkisofs -b boot/boot.img -c  boot/boot.catalog -o bootcd.iso
	  

The -b option specifies the boot image to be used (note the path is relative to the root of the iso9660 disc), and the -c option is for the boot catalog file.

Now burn the CD and its ready to boot!


Updated: Tue, 03 Feb 2004
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