DEC Pro 350/380 Memory Cards - Interchangeability?

Eric Smith spacewar at
Sat Sep 3 20:08:58 CDT 2016

I wrote:
> Mouser has some in
> stock, e.g., the IS41C16105-50KLI in SOJ-42 package at $7.20 each
> (quantity one) or the IS41C16105-50TLI in TSOP-44 package at $7.02
> each (quantity one).

On Fri, Sep 2, 2016 at 12:44 PM, Paul Koning <paulkoning at> wrote:
> The ISSI memory calls itself "DRAM with fast page mode", it does not say "EDO".  But judging from the timing diagrams (which show that data out turns off after the later of RAS and CAS deassertion) it sounds like "fast page mode" is a confusing way to say "EDO".

ISSI selection information refers to the IS41C16100C as EDO, and the
IS41C16105C as FPM.  I suspect that they were careless in preparing
the timing diagram on page 11 of the IS41C16106C (FPM) datasheet,
including footnote 1.

Another consideration in replacing legacy DRAM is that the x1 parts
have separate DIN and DOUT pins, while the wider parts have them in
common. Many but not all systems that use legacy DRAM tied DIN and
DOUT together. Using wider DRAMs in the systems that did not may
require additional buffers and control logic.

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