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15Nov/110

Linux Tips: How to force fsck on the next reboot or boot sequence

fsck is a file system consistency check and interactive repair tool.
Here is a quick tip that will show how you can tell your Linux system to perform a fsck on its partitions on the next reboot. Normally this will happen by default, after some time as configured in the filesystem at creation time (or changed later): after a number of days or a number of filesystem mounts.

If for some reason, you want to force the system to run fsck on the next reboot just use one of the following options:

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15May/111

FreeBSD: How To Install FreeBSD 8.x from USB Flash Drive

FreeBSD 8 can be installed from a USB memory stick. The required files can be downloaded via FTP:

i386: ftp://ftp.freebsd.org/pub/FreeBSD/releases/amd64/ISO-IMAGES/8.2/FreeBSD-8.2-RELEASE-amd64-memstick.img
amd64: ftp://ftp.freebsd.org/pub/FreeBSD/releases/amd64/ISO-IMAGES/8.2/FreeBSD-8.2-RELEASE-amd64-memstick.img

Insert the USB drive into the computer running Linux/FreeBSD and make sure it gets detect by the Kernel. You can check if the USB device got detect or not by running the following command:

dmesg
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31May/100

How to speed up the boot time in Ubuntu by profiling the boot process

There is way to improve the speed of boot process in Ubuntu Linux by profiling your boot. Profiling lets Ubuntu make a list of all the files that are accessed during bootup, it then sorts the files according to how they are stored on your hard-disk. So the next time the system is booted, the files would be read faster.

To profile boot you need to follow these steps:

  • At the grub menu highlight the kernel
  • Press e for edit
  • Choose the line starting with kernel and press e again. Now add the word profile to the end of this line. Hit Enter and then press b to boot

NOTE: The system will boot slower this one time, the next time however you should see an improvement. Also keep in mind that all this is machine-dependent and also depends on the arrangement of files on your hard-disk, so the difference you see might not be huge, or even nil in some cases.

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12Feb/101

FreeBSD: How To boot kernel.old

If you want to boot with an old kernel, because the current one is not working properly, this is what you have to do:
During boot you get a message like:
"Booting kernel in 10 seconds or press enter..."
Just hit any key except the ENTER key and you'll get a prompt.
Type 'unload all' and then 'boot [kernel file]' where [kernel file] is the kernel you want
to boot e.g. 'kernel.old' .

Your FreeBSD machine will boot with the kernel you specified.

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