Re: Larger memory option for VAXstations

[Felix Deichmann <m4j0rd0m0%gmail.com@localhost>]

2015-08-19 14:29 GMT+02:00 Johnny Billquist <bqt%update.uu.se@localhost>:
> That don't make sense. 36 x 4mx1 would mean 32 megs of memory. My VX4000/90
> have 128M of memory, and that was DEC original. So obviously DEC also made
> 16Mx1 based memory modules.

Pardon, but 36 x 4Mx1 means 16 MB of usable memory (considering
parity, i. e. 9 bit per byte).
36 x 4Mx1 = 150994944 bits, and 150994944 bits / (9 bit / byte) = 16
MB. Or am I completely wrong now?
And your VS4000/90 has the max. 128 MB from using 8 DEC original
modules with 16 MB each, right? At least my /96 is configured that
way.
I thought that for the VS4000, the 16 MB module was the largest
original one available.

> For 512 meg, why not locate 64Mx1 memory chips? Or did those not exist?

Might be even rarer than 4Mx1 or 16Mx1. And maybe the larger (and
therefore later) ones are only available as EDO, which could introduce
new trouble when the machine expects "plain" DRAM and its timing.
Don't know.
But this whole idea will require serious effort, fiddling and money...
Why not just buy a MicroVAX 3100/88 or /98, which is NVAX and seems to
support 512 MB by design? :)