Re: Apple IIgs ROM Disk

["Bryan Villados" <news002@macgeek.org>]

If anyone wants to see this card that David's talking about, check out the
card I sold on eBay awhile back:

http://www.macgeek.org/temp/octoram/

These are photos of the OctoRAM ESP with the 512KB pack. Pretty neat to play
with!

--- Bryan

"David Empson" <dempson@actrix.gen.nz> wrote in message
1fnv7m4.uqgsfq877393N%dempson@actrix.gen.nz">news:1fnv7m4.uqgsfq877393N%dempson@actrix.gen.nz...
> Bryan Parkoff <BParkoff@satx.rr.com> wrote:
>
> >     I don't see that ROM Disk is used by Apple Computer, Inc.  If it
does,
> > where can I obtain the information?
>
> Apple never supplied any hardware which provided support for the ROM
> disk, but there are third party products that support it.
>
> One example is the OctoRAM ESP card, which is a piggyback card that
> attaches to the OctoRAM.  The OctoRAM supports up to 8 MB of RAM using
> 30 pin SIMMs.  The OctoRAM ESP provides an additional 512 KB of battery
> backed static RAM, which is mapped into banks F0 through F7.  The driver
> has to be loaded into the card from disk, but after the next restart it
> appears as a volume called ROM5, with about 510 KB of storage capacity.
> There is a jumper which can be used to write protect the card after the
> appropriate data has been written to it, and the battery preserves the
> contents while the power is off.
>
> The driver is located at the start of bank F0.  The slot 5 firmware
> recognises the presence of a ROM disk by looking for the string
> 'ROMDISK' at location F00000, and the driver entry point is immediately
> after that.  The details are in the IIgs Firmware Reference.
>
> The main problem I had with my OctoRAM ESP is that the NiCd battery was
> unreliable, so I ended up removing it from the card and wiring in my own
> AA battery pack with separate Nicads, which I attached to the inside of
> the IIgs case.
>
> I also found it to be of limited use due to the small capacity: 512KB
> isn't enough for a GS/OS boot disk, but it might be sufficient for
> ProDOS-8.  If the write protect jumper is connected, it cannot be used
> for some software (such as AppleWorks) which requires write access to
> the boot disk.
>
> --
> David Empson
> dempson@actrix.gen.nz