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Re: Why the RamWorks III?
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In article <9eq4sa$8pd$1@venus.itns.co.za>,
Greg Wildman <gregw@venus.itns.co.za> wrote:
>On Sun, 29 Apr 2001 15:03:23 GMT, Greg Buchner wrote:
>> In article <3AEB8B47.2D7E3415@intergate.bc.ca>,
>> Wayne Stewart <waynes@intergate.bc.ca> wrote:
>>> Does anyone know or can guess why the RamWorks III was produced. Looks
>>> like they just rearranged some of the chips on the RamWorks II and
>>> renamed it.
>>
>> I do believe the redesign was so it would fit in the European IIe.
>> It was probably easier to just redesign the card and produce one for
>> the two different markets than it was to produce two different cards.
>
>Yes the European IIe had the auxilliary connector in line with slot 3 so the
>card sat further back in the case than the USA IIe.
IIRC, they also reduced the chip count by replacing some (most?) of the
74LSxxx logic with a smaller number of PALs. By setting the copy-protect
bit in the PALs, they could stymie most attempts at cloning.
On somewhat of a tangent, I bought a RamWorks II from an eBay seller a few
months ago. On the card, four of the chips have had their identification
ground off. The layout of the board is somewhat like this crude ASCII
drawing, with the mystery chips marked "????" and with connectors and
passive components omitted:
? ? L F 41256 41256 41256 41256 41256 4
L ? ? S 3 1
S ? ? 0 2 L 41256 41256 41256 41256 41256 2
0 ? ? 8 S 5
4 3 41256 41256 41256 41256 41256 6
L ? ? L L 7
L S ? ? S S 3 41256 41256 41256 41256 41256 4
S 5 ? ? 2 3 1
2 1 ? ? 4 7 41256 41256 41256 41256 41256 2
7 5 4 5
3 41256 41256 41256 41256 41256 6
Has anyone figured out what those four chips should be? While the logic
needed to keep all the memory refreshed and to make sure the video display
always pulls from bank 0 while the processor can access any bank isn't
trivial, neither is it exceedingly complex. On the off-chance that one of
the mystery chips croaks, what would replace it?
_/_
/ v \
(IIGS( Scott Alfter (remove Voyager's hull number for email address)
\_^_/ http://salfter.dyndns.org
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