WTB: DEC Rainbow Expansion Memory

Warner Losh imp at bsdimp.com
Sat Apr 15 11:32:27 CDT 2017

On Sat, Apr 15, 2017 at 9:56 AM, william degnan via cctalk
<cctalk at classiccmp.org> wrote:
>> Rainbow Memory Extension Option Installation Guide:    EK-PCMKE-IN
>> …Two versions of the memory extension option are available: a 64 K byte
>> option (part number PC1XX-AA) and a 192K byte option (part number
>> PC1XX-AB). The memory option is installed in the J6 connector …
>> …       Both versions of the memory extension option use the same printed
>> circuit board etch and the same type of 6kK x 1 bit memory chips. … the
>> 192K byte version contains twenty-seven 64K x 1 bit chips arranged as three
>> 64K byte memory stacks. ...
>>         From my Rainbow Owner’s manual 1st ed. Sept 1983, Appx. C, Table
>> C-1
>>>> 64K byte memory board option:   PC1XX-AC
>> 256K byte memory board option:  PC1XX-AD

I think that have what looks like the AD option, but it only brings my
Rainbow 100A up to 256k. I bought the 100A recently based on a seller
telling me it was a 100B. Grump. But at least its floppy controller
and drive are in much better shape than my old ones, so I have some
parts now. Just not sure what to do with them, but they may become
spare parts, which I might be willing to part with. Not sure yet.

Also, the boards themselves have numbers like 53xxxxxx and don't list
the actual part. So googling for them often involves googling for that
number because it's what sellers have easily available to them...

>> 64K byte memory component kit (9 chips) PC1XX-AY
>> 256K byte memory component kit (9 chips)        PC1XX-AZ
>>         Hope  this helps.
> Just chiming in...I am the person who provided Warner with the VENIX
> disks.  I probably have more RAM than I need in my machines (I have three
> and I think I have an A, B, and a regular Rainbow here.  All of this talk
> has peaked my interest to set mine up and see if the new Rainbow I just got
> this week works.  In addition to VENIX I have a lot of other disks and
> parts.

Cool! I've had much luck since we talked last. I'm 5 sectors away from
having all the disks read. Well, and understanding the encoding used
on the boot disk to store the serial number in a difficult to
replicate manner. At least I think that's what's going on. See
for a few details.

Unfortunately, the 5 sectors are on User disks 2 and 3, so are early
in the series, which may make all the other readable disks useless.
Not sure if there was compression at the time, so maybe it will just
corrupt a few files. This is out of 16 400k disks, so it's a quite
high percentage for them being so old.

Btw, anybody know what might be on an "Enhanced BWS Supplementary
disk"? A quick google search didn't bring up anything, but it's a
Version 7 Unix. I'm hoping it's the compiler, in which case I may be
able to reconstruct the missing material from the V7 sources.


More information about the cctech mailing list