From: cohen@GOMEZ.phys.virginia.edu
Subject: Re: Wanted: Gram Emulator
Reply-To: cohen@GOMEZ.phys.virginia.edu
Organization: Dept. of Physics, University of Virginia
Date: Fri, 18 Dec 1992 19:27:46 GMT

In article <009653DB.E1C7A860@GOMEZ.PHYS.VIRGINIA.EDU>, cohen@GOMEZ.phys.virginia.edu writes:
>In article <1gr7mjINNhpk@mirror.digex.com>, tstark@access.digex.com (Timothy M. Stark) writes:
>>      I am looking for the gram emulator and supercat modules. Does anyone
>>know where are them? If so, I will appericate that! Thanks you!
>>
>

In my previous post I gave a practical answer.  However, for general fun
it might also be of interest to present a brief history.

There is no such thing as GRAM.  GROM was TI's patented, top-secret (Lubbock-
era) self-incrementing type of ROM that did not just dump itself into
CPU RAM (of which there are only 256 BYTES in the console; the 16K there are
VDP RAM).  Using special circuitry it is possible to make the console
think it is accessing GROM while in fact it is regular RAM (SRAM, in fact,
for practical reasons).  Then you've got a "cartridge buster" that can
change RAM contents and thus run many different cartridges from a single
circuit (not all at one time, of course).
The first such device was built, no surprise, at TI and was called the
"GROM BOX".  It was for internal use only, though after 1983 a few unit made
their way to collectors and there was an article in Micropendium describing it
a couple of years back.

Next came the Gram Kracker from Miller's Graphics.  Like anything else that
Craig Miller did, it was superb in both its functinality, outside looks,
manual etc.  To this day, if you buy the GRAMULATOR or the P-GRAM card,
it is strogly recommended that you get the GK manual as well; 'nough said.
It not only gave the user the ability to save cartridges in RAM, disk,
or cassette (yes, that's right, you can put all your cartridges on cassettes
and run them from the bare console with a tape player!),
but also to change cartridges, and more importantly to control
the operating system.  At long last, the TI-99/4A operating system was
forced open, just like the the Apple DOS, CP/M, IBM PC (MS)-DOS, etc.
That was a major milestone in the user supported survival of the TI-99/4A.
(One cartridge that was born out of the GK is Super extened BASIC, incorporat-
ing in cartridge forms all the change to TI XB created with the GK.)
I have wondered, and never got an answer, whether MG built the GK on its own
(from scratch) or whether they got some insider info from TI to get them started
on the right track.

There is a whole list of such devices produced in larger or smaller quantities
over the years.  Was it Pike Creek that had this Module 6000 which let one
save cartridge to disk?  There is a little-know device sold in Belgium in
small quantities, and perhaps many more (in case you know of some others
please e-mail me with details).  They range from basic to very advanced.
One of the more advanced was the German GRAM Carte, which supports (in
multiple card configuration) up to MB's of GRAM, I think.  These devices
have file header different from those used by the U.S. devices (GK, Gramulator,
P-gram, Geneve) and the European users can better comment on them.

The Geneve has a GROM simulation built-in, so it will run most GK files
(subject to its incompatibilities with the TI-99/4A), but it cannot do the
other tricks that the GK does (nor is this required with a disk-based DOS,
for the most part).  Anyway, I think there are less Geneves out there than
GK and equivalent units anyway...

It is also of interest to note the one can dump catridges to disk in GK
format without using the GK itself (but to run those files you will need
the GK).  So, if you know somebody with a rare cartridge, he can dump it to
disk and you could run it on your GK (if you have one) even if he has no GK.


It is unfortunate that there is so little support for the GK devices in this
community.  The only real piece of software created with the GK that I know
of is Super XB.
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