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Re: ROM-Drive Project Update
On Mon, 12 Jul 1999 06:48:05 -0800, Terence J. Boldt
<apple2@cgocable.net> wrote:
>Currently I have a 4Mb (512KB) EPROM in the test system.
>The drive supports 8Mb (1MB) but I don't have any of those
>chips (anyone know a place in the Toronto area to get
>27C080 EPROM's in a DIP package?). Anyway, that's a lot of
>space for 8 bit software. I have not tested the board on a
>IIgs but it's not big enough to do much with GS/OS.
I don't know if any of the electronics stores in Toronto I used to
visit are still in business. There is Active (not Active Surplus
although that is always a fun place to look) and I know there are a
number of electronic component stores. There are one or two on Queen
Street West between Yonge and Spadina but I don't know what all they
carry.
If you can't find the 8 Mb EPROM, why not use two 4 Mb ones? For that
matter, why not use four or more? You address decoding circuit would
need to be altered a bit but you could offer larger capacity ROM
Drives that way.
Personally, I had toyed with the idea of making an EEAROM Drive card
several years ago. An EEAROM, for those that don't know, is an
Electrically Eraseable and Alterable Read Only Memory. This means
that it acts like a ROM but with extra circuitry can be erased or
changed by the processor. I always though this would be a great thing
for making a GS/OS boot disk but patching things (some of the patches
already exist) to load fonts, DAs, inits, CDEVs and such from a disk.
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