CDC Core Memory
In early 1997 we had the great opportunity to capture a few of these memory
modules. They were found at the Michigan State University Salvage Yard and
sold for scrap metal. At one time, and probably until the late 80's,
MSU was renting out some space to CDC for a service and maintenance field office
[is Jeff Sheltron (sp.?) out there].
I imagine someone at MSU got excited recently about cleaning out some
old cabinets with these leftover spare parts.
We are guessing that the brick in the pictures below is a CDC core memory module from one
of the 6x00 computers. This module is approximately 6 3/4" x 6 3/4" x 3 3/4",
and hides 12 planes of core memory. The module is 12 bit wide by 4096 memory locations.
The electronics surrounding the matrix of cores seems to include the x and y
current drivers and the inhibit line drivers, but not the sense amplifiers.
This was clearly a very labor intensive assembly process (even without counting
the threading of 50,000 cores!) that produced a very compact
module where performance might have been the issue... not cost.
I am just a bit too young to have done much with computers of that era.
Furthermore fate had it that I spent most of my time with DEC hardware.
There are 3 of us electronics engineers here in the
physics department sharing this enthusiasm for old computers.
We sure feel lucky to have been able to save a few of these modules from being
melted down to make more PC enclosures....
What a great piece of engineering and what a great window to the past!
One of the twelve Planes (not from THIS module)