What is cold boot, warm boot?

Posted by Shashank Krishna Thursday, January 8, 2009

sharethis: Hard reboot

A hard reboot (also known as a cold reboot, cold boot or cold start) is when power to a computer is cycled (turned off and then on) or a special reset signal to the processor is triggered (from a front panel switch of some sort). This restarts the computer without first performing any shut-down procedure. (With many operating systems, especially those using disk caches, after a hard reboot the filesystem may be in an "unclean" state, and an automatic scan of on-disk filesystem structures will be done before normal operation can begin.) It may be caused by power failure, be done by accident, or be done deliberately as a last resort to forcibly retrieve the system from instances such as a critical error or virus-inflicted DoS attack. It can also be used by intruders to access cryptographic keys from RAM, in which case it's called cold boot attack.

[edit] Soft reboot

A soft reboot (also known as a warm reboot) is restarting a computer under software control, without removing power or (directly) triggering a reset line. It usually, though not always, refers to an orderly shutdown and restarting of the machine.

The Control-Alt-Delete key combination on the original IBM PC was designed to allow a soft reboot for a quicker and more convenient (and, some argue, less stressful on system components) restart than powering the computer completely down then back up.[citation needed]

The Linux kernel has optional support for the kexec system call, which shuts down the currently running kernel and executes another one. The entire process is done independent of the system firmware. Note that the kernel being executed does not have to be a Linux kernel.

Most Nintendo Game Boy games feature a soft reset feature when the A, B, Start, and Select buttons are pressed together. This was carried over to the Nintendo DS, with the sequence L, R, Start, and Select. Many Nintendo GameCube games have a similar feature, with the sequence Start, B, A, and X.


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Shashank Krishna
Bangalore, up, India
nothin much to say.........doin B.tech in IIIT allahabad loves bloggingn hacking.... :) and loooves blogging
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