Ram disks

[ron at brl-bmd]

From:      Ron Natalie <ron at brl-bmd>

We've been so pleased with "RAM" disks that we've ordered
one for practically all our machines.  I should note however,
that we haven't bothered trying it with 34's.  We do use it
for our 11/70's and VAX's.  Since we figured we didn't swap
all that much we use it primarily for /tmp.  Sure speeds up
C compiles.  One system also uses one for the root, which contains
/bin, /lib, and /etc (/tmp is on another RAM and /usr is on disk).
That helps a lot too.

What we use are DATARAM bulk core and bulk moss.  We use the
one bulk core for the root on the one machine and the mos units
everywhere else.  The mos units are available with battery backups.
The DATARAM MOS units also come with dual unibus ports (although
we only use one) and built in error logging and diagnostic routines.
They will emulate either DEC RF or RS fixed head disks.

I have had some exprerience with AMPEX's MEGASTORE and a little with
a thing called a MAXIRAM.  The main problem with these is that the
RS04 is a little more difficult to program if you would like to treat
each collection of 1Mbyte logical drives as a larger single unit.
The RF style controller automatically (because the old DEC hardware
it is emulating) knows how to switch from drive to drive automatically.

The reliability of the Dataram has been fairly high, and so was the AMPEX.

-Ron

P.S.  Anybody thought of putting /bin in ROM?