what happens when you hit the reset button

[rookie1010]

Hi
What happens when we hit the reset button.
i mean does it kill the power to everything, or the pwoer is still there, and it just resets the processor to memory location 0(program counter = 0??)

 

[ChaosBlizzard]

It shuts the system down without removing power, and then starts the system back up as it would when you just turn the computer on, meaning bios performs post and then hands the operations over to the OS. The cache, to my knowledge, isn't cleared.

 

[kboy]

I don't know if a soft restart would clear the cache or not, Good question. Hmmm?

 

[ccohn2000]

Alright, speaking from ignorance( mine of course! ), something must not get cleared during a soft restart, otherwise it would perform exactly the same as a cold boot, and it doesn't always. The cache seems like a good thought.

 

[Target]

Processors have a reset pin that when grounded will cause the processor to reset, clearing all the on-chip memory. Your RAM may or may not clear its contents. Your other devices should still have power to them.

A hard boot will shut power off to everything.

-Target

 

[rookie1010]

what do you mean by cache?
the RAM or the cache on the processor.

are the contents of the RAM erased or the cache or both?
and am i right to assume that the PC is reset to 0x0?

 

[killians45]

A soft reset only resets the initialize code given over from the bios, and the hardware that has there own 'reset' on power cycle are not effected. It will essentialy put the hardware passed from the bios during the bootstrap and pass a software 'reset' code to put them in a default KNOWN STATE. Doesn't always work, though, because some have own reset code for a power cycle. Thats usually when the reset wont work, and it has to be Cold booted. When doing a reset, it usually will bypass the POST, since it does not need the info passed from bios, it will take existing info and set the master reset to a high state, or turn the reset on.