[P1] Booting a Computer

[Brian Pearce]

> A RAM disk is a portion of RAM set aside for certain files. If you 
> have a RAM disk, zapping the PRAM or resetting the Power Manager will 
> erase whatever you have on the RAM disk.

There's a bit more to it than that; a RAM disc, as you say, uses a 
portion of your RAM to create what appears to be just another disk; you 
can put whatever you want on it. The advantages of doing so are quicker 
access to data, particularly with larger files (since they can be read 
out of RAM much faster than from a hard disc) and slightly less battery 
consumption (since you're not repeatedly spinning up a disc to read 
information from it).

The disadvantage is that it's a more volatile form of storage than a 
hard disc. An image of the RAM disc would need to be saved between 
restarts, to be reloaded; it's even better if it's saved on a more 
regular basis, since an unexpected crash will cause the contents to be 
lost. (And of course, you lose whatever you've set aside for a RAM disc 
from the memory for programs to operate in.)

Back in the day (mostly before the iBook), a RAM disc was a useful tool 
to employ with a portable computer to help conserve battery power.

BRIAN/bpearce at cloud9.net