Post by MG Post by Hugh Hood
I think, however, my favorite thing about the IIGS as a 'Super' IIe is
this — it can use the _wicked_ fast RamFAST Rev. D SCSI disk controller,
which gives one, even today, unmatched 8-bit ProDOS speed on an Apple II
An Enhanced //e can use the RamFast Rev. D, my main //e has one.
It is wickedly fast on the //e, as well.
You are correct. In _some_ cases, an Enhanced IIe can use a Rev. D
RamFAST. In fact, I have one in a IIe.
My mistake, made in the hope of being concise, was to paint with too
broad of a brush. So, ...
With apologies to Anthony for detouring his thread a bit, here is the
'story' of the IIe / RamFAST (Rev D) combination, as I learned it from
Joseph Yandrofski and Jawaid Bayzar of Sequential Systems, and also Drew
Vogan of CV Tech.
1. The RamFAST Rev. D was a low power version of the RamFAST Rev. C. It
used HCT chips instead of LS chips and worked quite well in the Apple
IIGS. Unfortunately, the Apple IIe had what was described to me as a
'noisier' bus, and the lower power 74HCT chips could not deal with that
cleanly, and data transfer reliability suffered, which is terrible when
you're writing to hard disks.
Hence, at first the Rev. D was just marketed to IIGS owners. IIe owners
were instead instructed to use the Rev. C board.
2. Sequential Systems, hoping to sell just one RamFAST board, made a
special version of the Rev. D board that used 74LS chips to drive the
bus (there may have been another series chip as well, IIRC) in place of
the 74HCT chips.
One had to order that board separately. I have either (1) or (2) of
those, and they work fine in a IIGS as well as in a IIe.
3. Bus issues aside, the Rev. D would work with the AE Transwarp IIe
accelerator _provided_ the DMA feature of the RamFAST was disabled. I
have tested this combination and it works fine, although I'm not sure
how much speed is being lost by not using DMA. In any case, the caching
feature still works and it is very fast.
4. Here's the deal-killer, or at least it was for me at the time -- No
Rev. D board would work with the 8 MHz Zip Chip installed in the
machine. The machine would hang on boot, and not even disabling the DMA
feature would make it work.
Acknowledging that the problem existed, Joe Yandrofski asked me to send
him a Zip Chip so that he could see how the situation could be remedied.
Unfortunately, even after several months Joe never was able to get this
fixed, and eventually Sequential closed their doors.
FWIW, the Rev. C RamFAST _could_ be modified to work with the 8 MHz Zip
Chip. Jawaid required the board back at the shop and he would, IIRC,
re-program the DMA Pal and something else. I never owned a Rev. C (very
power hungry), but Chet Day (I think it was Day - 20+ years ago is
taxing me) did and he sent several back to have the mod done.
He was most pleased, as he was a IIe guy.
This very topic was discussed at length in the old GEnie Apple II
Rountables. Thanks to David Finnigan's MacGui.com, here is just one of
_many_ threads discussing the Rev. D in a IIe, and also the Rev. D with
the Zip Chip.
What will be *most* interesting to see will be if the Rev. D RamFAST (LS
chips) will work with Plamen's FastChip//e. I have yet to hear a report
on that combo.