Re: Zip GS questions

[spec@vax2.concordia.ca (Mitchell Spector)]

In article benlai@unixg.ubc.ca writes...

>As a new IIgs owner, I am a little bit confused about the Zip
>accelerator for the IIgs..
> 
>At EGO System, they are selling a "ZipGS 8/16 accelerator", what does
>the 8 and the 16 stands for?  They claimed that the chips runs at 8 mhz,
>so I assume the 8 stands for megahertz, and the 16 stands for cache
>pershaps?

    Your correct. An 8/16 model ZipGS simply means that - 8 MHz/16K cache.
Through the years, REMCorp (formely MTCA and before that Zip Technologies)
sold several configuration models, the most common were: 7/8, 8/16, 9/32
and 10/64. These are not fixed configurations however, you can mix any
megahertz rating (from 7 MHz up to around 16 MHz) with any of the four
cache sizes: 8K, 16K, 32K and 64K.

    These days, unless I'm mistaken, the only off-the-shelf ZipGS you
can purchase _new_ is the 8/16 model. If you want to upgrade it, you 
either send it back to REMCorp and pay their fees for parts and labour,
or, do it yourself (although that voids your warranty on a new card).

>Yet, at Alltech they are selling 7mhz Zip Chips for a lot cheaper than
>the ones by EGO System ($140 versus $175), what is the difference
>between the two?  

    I would assume these are refurbished boards, especially when you 
consider that the 7/8 model was discontinued a few years back. As for
the difference between models, there really isn't any, if your looking
at the board itself. They only differ in what chips are plugged in:
The static RAM, processor and crystal oscillator that sets it's speed.
As I said above, no configuration is fixed, it just refers to how it
is shipped out of the box. 

    Generally, due to the way it functions, when faced with a choice,
it is better to choose more cache over speed. For example, an 8/64
would outperform a 10/8. The absolute highest configuration possible
at the moment is a 16/64 (at least I *think* this has been done, I 
myself have a 15/64, and I know a few people who've had/have 15.5/64).
Then there is the split-cache (128K) but I know very little about this
modification, or whether it even improves performance.

>Also, I remember reading something about Zip GSX, what are these?

    The ZipGS is the "ZipGSX", most people just simply call it by
the former name. There was a ZipChip GS, a slotless version of the
ZipGSX that was a little circuit card, it plugged directly into the 
CPU connector on the motherboard. It never made it past the prototype
stages however (you can see images in early InCider/A+ ads); I don't
think any were ever sold either.

    There is also the ZipChip, it was an acceleration product for
the 8-bit Apple II, II+, IIe and IIc. It replaced the 6502/65C02
with a slightly taller chip, in either 4 MHz or 8 MHz configuration.
It had 8K of cache built-in (8K for 'tag', 8K for 'data'), and it's
design concept was later used in the Apple IIc Plus. It is no longer
manufactured or sold. The ZipGSX, last I heard, is still in limited
production.

Mitchell Spector
spec@vax2.concordia.ca