9 Jun
2004
9 Jun
'04
12:39 p.m.
okay, 16 - 256kx1 chips will not give you 2meg... it is only 0.5meg. If the docs you have
say 256kx4 then that is the chip you need and the ones on the ISA board are not the right
ones.
the 256Kx4 DYNAMIC ram chips that you would need were usually used in VGA cards for
display memory.
best regards, Steve Thatcher
-----Original Message-----
From: Bill Sudbrink <wh.sudbrink(a)verizon.net>
Sent: Jun 9, 2004 8:22 PM
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk(a)classiccmp.org>
Subject: RE: Cheetah Cub board
Back to the DRAM nomenclature, the 1 bit vs 1 byte
explanation helps a lot. I'm still confused about
the multiplier.
The Amiga docs show 16 256Kx4 DRAMs for a total of
2MB, so does that mean that these chips are 256Kx1?
Exactly!
9 Jun
9 Jun
12:59 p.m.
Steve Thatcher wrote:
okay, 16 - 256kx1 chips will not give you 2meg... it
is only 0.5meg. If the docs you have say 256kx4 then that is the chip you need and the
ones on the ISA board are not the right ones.
the 256Kx4 DYNAMIC ram chips that you would need were usually used in VGA cards for
display memory.
Yes, I actually found the chips I need for the Amiga on a couple of
busted MCA graphics boards. No ROMs on either, and one looks like
somebody practiced their solder-sucking on it, so I'm not killing good
kit for them.
After physically looking at the A2091, I also found that it wants
20-pin DIPs, not 16-pin DIPs. :)
This upgrade isn't really just a system RAM boost. The A2091 SCSI
chip can't write to the GVP 32-bit RAM in that box, so it's doing
programmed-I/O transfers. At roughly 80MB/hour, disk-to-disk. The
on-board 16-bit memory will allow it to breathe. I hope.
Thanks, Steve, Tony, Bill, Brian, Gene, and everybody for the
tutorial. It helped a lot. Now, instead of being afraid to pick up the
gun, I can go shoot off some toes.
Doc
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