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SubjectRe: Encrypted Swap
On Aug 17, 2001  11:51 -0700, Nicholas Knight wrote:
> Now that we've established that SDRAM doesn't neccisarily get erased from
> rebooting, does anyone know how long it takes for SDRAM to clear after
> losing power? It seems to me that the fact that the RAM isn't neccisarily
> wiped by the BIOS at boot is less important than wether or not shutting
> down the system and having it shut down for 10 minutes causes the RAM to
> be cleared so that any intruder/thief would be unable to get the
> information neccisary to decrypt the swap...

Hmm, it was my understanding that all PC BIOSes DO zero out memory,
although this is not necessarily a requirement of the hardware. The
reason I say this is because one of the features of the Linux BIOS
project is to allow crashdump analysis after a reboot, by pulling
the dump from the RAM after a reboot. You apparently are not able
to do this with normal PC BIOSes because they clear the RAM after
a reset.

That said, I'm not sure what the requirements of different kinds of
RAM chips are for initialization, so there may not be a REQUIREMENT
to clear the memory, but rather it is part of the nebulous "PC spec".

Cheers, Andreas
--
Andreas Dilger \ "If a man ate a pound of pasta and a pound of antipasto,
\ would they cancel out, leaving him still hungry?"
http://www-mddsp.enel.ucalgary.ca/People/adilger/ -- Dogbert

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