freezing system state

[Donald Becker]

On Thu, 14 Sep 2000, Eugene Leitl wrote:

> Can anyone point me towards information how I can snapshot the entire
> system state to hard drive, and have an option to restore it at boot
> time?
> 
> If Linux can't do that yet, are there plans for putting support for
> suspend state into it?

As many people have already responded, laptops can suspend to and recover
from disk, but most non-laptop systems cannot.

Most older PC hardware has hidden registers that the OS cannot recover.
A major problem is the standard PC video adapters, serial ports and sound
cards.

Laptop BIOSes avoid this problem by knowing the details of the hardware.
The only unknown hardware is PCMCIA cards and USB devices, recent devices
which the OS must explicitly handle.

Read the datasheet of a laptop support chipset to understand the problem,
and the many hooks into the "PC standard" hardware to work around it.

Sun hardware is much the same as a laptop -- Sun has complete control over
the hardware design of the system.  (Open Firmware plays a role as well.)

Donald Becker				becker at scyld.com
Scyld Computing Corporation		http://www.scyld.com
410 Severn Ave. Suite 210		Beowulf-II Cluster Distribution
Annapolis MD 21403