Re: Zip Chip

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

In article <245335168wnr@klatch.demon.co.uk>,
John Le Febvre  <john@klatch.demon.co.uk> wrote:
> In article: <7982.93611355@adbbs.antioch.edu>
> John_L._Graham@adbbs.antioch.edu (John L. Graham) writes:
> > 
> > We just bought a ZipChip-8 from Alltech (1-619-724-2404). This is a
> > bad sign, I've nearly got Alltech's telephone number memorized....
> > and it's not even a 1-800 number!
> 
> A quickie question these, as I know nothing about them...
> Are they just a chip replacement or a card?  Enquiring minds wish to know...
> (I see another slot being freed if it's not a card...)

The ZIP CHIP (for the Apple IIe or IIc, and possibly the II+) is a
single chip (taller than usual) the plugs into the microprocessor
socket, in place of the 6502/65C02.

There were two versions made: 4 MHz and 8 MHz.

There is also the "Rocket Chip", from Bits and Pieces, that is very
similar in design, and was available in 5 MHz and 10 MHz versions.
The Rocket Chip was not available for as long as the ZIP chip, because
ZIP sued Bits & Pieces (I assume) over the design (it violated ZIP's
patents) and its production had to be stopped.


The ZIP GS, on the other hand, is a card that plugs into a IIgs slot,
with a cable running to the 65816 socket on the motherboard.

The TransWarp GS is a similar (but larger) design.

The TransWarp for the IIe is also a card-based design, but it doesn't
have a cable running to the microprocessor socket.


One point to note about IIe accelerators: none of them support Direct
Memory Access, so you must disable DMA if you have an Apple High-Speed
SCSI card or a RamFAST SCSI card.  This will slow down disk accesses,
but the increase in processor speed is probably more significant.

This doesn't apply to the IIgs accelerators - both work with DMA, but
there is a conflict between the TransWarp GS and the RamFast SCSI card
that causes problems when DMA is used.  (I think you have to enable a
special option on the RamFast to get around this.)
-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand