DEC MM15 core mem found

Rich Alderson RichA at
Tue Dec 8 15:42:27 CST 2015

From: Pontus Pihlgren
Sent: Tuesday, December 08, 2015 4:03 AM

> I've seen a memory assembly from a PDP-15 and it looks very much like 
> this. Also, if each connector pair corresponds to one bit it adds up to 
> 18 which matches the word lenght of a PDP-15.

> Of course, PDP-1, -4 and -7 used 18 bit word lenght, but they were not 
> made with flip-chips.

Flip Chip technology was invented for the PDP-7, after the failure of the
large System Modules used in the PDP-6.  The only part of the PDP-7 which
uses System Modules(TM) is the DECtape controller for the 555 DECtape

If you'd like to visit the museum, I'll happily show you the internals of
a running PDP-7. :-)


Rich Alderson
Vintage Computing Sr. Systems Engineer
Living Computer Museum
2245 1st Avenue S
Seattle, WA 98134

mailto:RichA at

More information about the cctalk mailing list