EARLY DEC 4K (!!!) Core MEmory card

Flip Chip PDP-8 Planar Stack Core memory card DEC computer hardware

[Maynard, Massachusetts]: Digital Equipment Corporation. Measures approximately 8 1/4 x 10 1/2 inches. Rear of card has markings including "8K OR 4K x 12 BIT STACK BD G646C" in solder on the board. "DEC H-212-14370" under varnish in back. "M07370750" on white sticker. Overstamped with square box and "MO 70" inside. Digital sticker noting DEC P/N (H-212), SERIAL (7735-F- -14370) and SIZE (8K x 12 (175)).

Front of board has "FLIP CHIP (R)" in solder on board. Center of board consists of memory cores (very fine) with 12 banks. Two "Digital WARRANTY VOID IF SEAL IS BROKEN" affixed to protective plastic shield. Good. [29224]


An early DEC computer memory card. It is very, very cool, and would look great framed if you added a magnifier built in to see the small cores!!!. We have no way to test it so it is being sold as is, as a historical computer artifact. These are getting a lot harder to find, as most were scrapped years ago for metal content.

"Flip Chip" which was a module used by Digital Equipment Corporation starting in 1965. It is a core memory card, with many, many small ferrite cores each with wires threaded through them. There are 24 banks of cores. These would have been used in early DEC computers.

From wikipedia :
"The 12-bit PDP-8, produced by Digital Equipment Corporation (DEC), is the first successful commercial minicomputer. DEC introduced it on March 22, 1965 for a price of US$18,500, and eventually sold more than 50,000 systems, the most of any computer up to that time. It was the first widely sold computer in the DEC PDP series of computers (the PDP-5 was not originally intended to be a general-purpose computer). The chief engineer who designed the initial version of the PDP-8 was Edson de Castro, who later founded Data General.

The earliest PDP-8 model (informally known as a "Straight-8") used diode-transistor logic, packaged on flip chip cards, and was about the size of a small household refrigerator.

This was followed in 1966 by the PDP-8/S, available in desktop and rack-mount models. By using a one-bit serial arithmetic logic unit (ALU) implementation, the PDP-8/S was smaller, less expensive and slower than the original PDP-8. The PDP-8/S was about 20% of the cost and about 10% of the performance of the PDP-8. The only mass storage peripheral available for the PDP-8/S was the DF32 disk.

Later systems (the PDP-8/I and /L, the PDP-8/E, /F, and /M, and the PDP-8/A) returned to a faster, fully parallel implementation but used much less costly transistor-transistor logic (TTL) MSI logic. Most surviving PDP-8s are from this era. The PDP-8/E is common, and well-regarded because so many types of I/O devices were available for it. It was often configured as a general-purpose computer."

Price: $350.00