[comp.sys.mac] OK to use Mac RAM cache?

alex@grian.cps.altadena.ca.us (Alex Pournelle) (03/28/90)

Until recently, I didn't have but the 1Mbyte in my Plus, but with
2.5Mbytes it's a valid 'un...

Is it really safe to use the Mac General CDEV's RAM cache?  I had heard
(this is another one of those vaguely recalled hacker's tales, possibly
in need of dispelling) that they were deferring writes and cache
coherency wasn't guaranteed at shutdown.  So, in the immortal words of
WIlliam Golding: "Is it safe?"

	Alex

rcfische@polyslo.CalPoly.EDU (Raymond C. Fischer) (03/29/90)

In article <1990Mar28.105508.2967@grian.cps.altadena.ca.us> alex@grian.cps.altadena.ca.us (Alex Pournelle) writes:
>Is it really safe to use the Mac General CDEV's RAM cache?  I had heard
>(this is another one of those vaguely recalled hacker's tales, possibly
>in need of dispelling) that they were deferring writes and cache
>coherency wasn't guaranteed at shutdown.  So, in the immortal words of
>WIlliam Golding: "Is it safe?"

Yes, it's safe.  I've had the RAM cache turned on for a year now on my
5Mb SE/30 and have had no problems.  If you select shutdown from the special
menu in the finder before turning off the computer, the integrity of your
disk is assured, and your Mac will start faster the next time you turn it on.
The only place you're at all likely to have problems is if the power to your
Mac cuts off unexpectedly, in which case it's kind of a crap shoot anyways
as regards to your data.

Ray Fischer
rcfische@polyslo.calpoly.edu