Recoverable RAM Disk
Just wondering - has anyone ever given any thought to the idea of a RAM disk that is not erased on a warm boot?
Obviously this is a bit architechture-specific - I don't think it's easily do-able on i386, but maybe it is other architechtures?
The idea of a recoverable, (even bootable), RAM disk was common on the Amiga, and it would be useful to, E.G. quickly re-boot in to several different kernels.
John.
Quoted 4 lines · [email protected] wrote:
Just wondering - has anyone ever given any thought to the idea of a RAM disk that is not erased on a warm boot?
Obviously this is a bit architechture-specific - I don't think it's easily do-able on i386, but maybe it is other architechtures?
We did it for a product using PowerPC on compactPCI. Critical logs are stored in ram beyond what the kernel uses, and it can be mapped in for processes to use it.
As long as the card has power, the information remains available, including resets of the card.
The only tricky bit is that I don't know if a warm boot on a PC wipes ram or not...
Chris
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Chris Friesen | MailStop: 043/33/F10 Nortel Networks | work: (613) 765-0557 3500 Carling Avenue | fax: (613) 765-2986 Nepean, ON K2H 8E9 Canada | email: [email protected]
Quoted 2 lines
The only tricky bit is that I don't know if a warm boot on a PC wipes ram or not...
Normally it does, but in the old days, you could - in DOS DEBUG or somewhere set 0040:0072 to a given value and then jmp f000:fff0.
IIRC, the value in 0040:0072 was these:
0x0000: cold reboot0x1234: warm reboot0x5678: warm reboot without memory clear
hæpp
roy
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Roy Sigurd Karlsbakk, Datavaktmester Computers are like air conditioners. They stop working when you open Windows.