Anyone know where uPD2167 SRAMs appeared?

[Josh Dersch]

On Tue, Oct 9, 2018 at 5:14 PM Ethan Dicks via cctalk <cctalk at classiccmp.org>
wrote:

> Hi, All,
>
> I asked a version of this question earlier this year.  I have not been
> able to find any vintage machines that used these 16Kx1 55ns SRAMs.
> Anyone recognize them?  Lots of them for sale on eBay.  Probably few
> buyers.  One would want to know which systems used them, thus my
> question.
>
> They probably would have been excellent in a DEC MOS memory board but
> I have no evidence they were used thusly.  Contemporary DRAMs were
> cheap and 64Kx1 so that's what was in consumer gear.
>
> Anyone?  Fast SRAM?  Anywhere?
>

The Three Rivers PERQ used 48 of them for microcode store in the 16K CPU,
and on the Z80-based IO Processor.  (I suspect the IO Processor didn't need
RAMs quite that fast, but 3RCC probably had a lot of them on hand due to
their use in the main CPU...)

- Josh



>
> There's little point in wiring 8 of them up into a byte vs using a
> 62256 except for speed.  55ns is faster than any 8MHz machine really
> needs (100ns-150ns was typical for those depending on bus
> architecture).  I could see these being cache RAM for a minicomputer
> vs primary RAM.
>
> -ethan
>