Re: ][GS Questions

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

Frank Carney <frankc@cyberhighway.net> wrote:

> That is the problem it has these stand up chips in it.

Are the pins arranged in a zig-zag pattern?  If so, the card is using
ZIL/ZIP (zigzag-in-line) RAMs.

The ZIL/ZIP connector looks something like this:

  ---------------------
 | o o o o o o o o o o \
  \ o o o o o o o o o o |
   ---------------------

Whereas a standard dual-in-line RAM socket is rectangular, like this:

 -------------------
|o o o o o o o o o o|
|                   |
|o o o o o o o o o o|
 -------------------

The ZIL/ZIP RAMs are functionally identical to standard dual-in-line
RAMs of the same capacity.  You just need the appropriate package.

If the card requires 20-pin RAMs, then it needs 256Kx4 RAMs (e.g.
Hitachi HM514256AZP), not 1Mx1 RAMs (e.g. Hitachi HM511000AZP), which
have 18 pins.

There is a very small possibility it might expect 1Mx4 RAMs (e.g.
Hitachi HM514400ZP), which also have 20 pins.

I think the card is supposed to support 4MB in total (judging by its
name), so this can be determined by counting the sockets on the card.
If there are 32 sockets, then it needs 256Kx4.  If there are 8 sockets,
then it needs 1Mx4.

On the other hand, it might have an upper limit of 1MB using 256Kx4
RAMs, which would also be eight sockets.


Unless you can find a cheap source for the right type of RAM, I'd
recommend getting a different card.  If it is using 256Kx4 RAMs and has
a total capacity greater than 1 MB, then it is probably not compatible
with DMA (except the RamFast card).

-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand