Core Memory Module

These Core Memory Modules were manufactured by Data Products (Core Memories, Inc) of Hong Kong. They are serial numbers HT522 and HK175 and were donated by Randy Lyons of West Chester Pennsylvania. Rany Writes:

"I came across a pair of computer modules from the early 1970's called "Core Memory." Each is an assembly of three printed circuit cards, roughly 7.5 inches long by 11 inches wide by 2.5 inches thick. (See Photos)

The middle printed-circuit card has the actual memory devices, which are hundreds of tiny little iron "donuts" which are kept in place by a thin wire running east/west and another running north/south. This gives each donut a unique read/write address. Each donut represents a computer memory "bit," as it has a magnetic field that either runs clockwise or counterclockwise around the donut. Some research suggests that the entire module had a memory capacity of 8K bits.

These modules came from a mainframe computer that took up 3 cabinets the size of refrigerators. And the computer required 6 or 8 of these memory card assemblies in one of those cabinets to function normally.

One of the photos show the interface card between the core memory assembly and the computer’s backplane data bus. (For fairly obvious reasons, the card was called the “bus driver” module...) I haven’t disassembled the module to get access to the inner Core Memory card, as the mounting screws needed to get to the center of the assembly required better screwdrivers than I currently own. I have, however, seen other middle cards with all the donuts on display – and it’s an incredible sight!

Both modules are in extremely good condition -- and I rescued them from the dumpster at Leeds & Northrup Company, where I worked back in 1975. I asked my boss at the time if it was okay to keep them, and he said "Absolutely!" So provenance on the modules is not an issue. "