Re: ROM 3 and the Octoram

[dempson@actrix.gen.nz (David Empson)]

In article <1994Apr2.123050.16524@chemabs.uucp>,
Larry W. Virden <lvirden@cas.org> wrote:
> I seem to recall that there is a method for allocating some of the octoram
> as /rom disk.  This technique was used in the past to use the extra memory
> that the GS could not normally access.  Anyone have details on that?

As far as I know, there is no way of setting up a ROM disk with a
standard OctoRAM card (unless there is a newer version of the card,
which i doubt).

There is a piggy-back card for the OctoRAM called the "OctoRAM ESP",
for "Extended Static Pack".  This provides up to 512k of static RAM
with battery backup.  A jumper is used to enable or disable write
protection.  The RAM appears in memory locations $F0/0000 through
$F7/FFFF, which is where the IIgs SmartPort firmware looks for a ROM
disk.  Prior to using the card as a ROM disk you have to run a
pre-boot program which loads a device driver into the card.  When you
next reboot, you will have a /ROM5 volume available via the Slot 5
firmware (similar to /RAM5).

The original driver supplied with the card was rather buggy, so I
rewrote it.

My OctoRAM ESP is out of commission at present (and has been for a few
years) - my card's battery went flat (and wouldn't recharge), and I
sold my OctoRAM (but not the ESP card).  I then sold the RAM chips on
the ESP card, and eventually bought my OctoRAM back again when I got a
second IIgs.

I haven't bothered to set the ESP card up again, because it would cost
a reasonable amount of money to buy the RAM chips, and 512k isn't a
particularly useful size (not big enough for a IIgs system disk, for
example).

I'd rather build my own card using 128KB static RAM chips, with bank
switching to provide at least a megabyte...
-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand