IBM System/360 16Kb Core Memory from a S/360 Model 25
About this Core Memory
This listing is for an IBM System/360 magnetic core memory board. This board was from an IBM System/360 model 25 mainframe computer. This board dates from about 1968, 50 years ago. It contains 16,384 cores, or 16Kb, of memory. The core plane is 6.25 inches x 6 inches. I have included three pictures of the board: front and back sides and a closeup
About the IBM System/360
In 1961, IBM had about 65% of the market for computers. However, IBM’s existing computers were all incompatible. IBM needed a new approach to computing if it was going to gain, or at least hold on to its market share. IBM needed to step up its game. CEO, Thomas Watson Jr., bet $5 billion when IBM was only making $2.5 billion a year, that the IBM System/360 was the answer.
The introduction of the System/360 in 1964 was a major milestone in computer history. IBM made the commitment to its customers that if they rewrote their programs one more time, for the System/360, they would never have to do it again. To make this happen the System/360 architecture had to be fundamentally different from any computer that preceded it. The System/360 had an incredible number of firsts!
- First commercially available computer whose design is based on computer chips
- First family of compatible computers
- First to use micro-coding of the instruction set with emulation of a previous generation of computer
- First to guarantee compatibility with future generations (360 code will still run on today’s IBM computers)
- First to use 32-bit words
- First to use the 8-bit byte
- First to use byte-addressable memory (as opposed to bit-addressable or word-addressable memory)
- First to use key-controlled memory protection
- First to have a standardized I/O channel architecture (FIPS-60.31) which allowed interchangeable I/O devices
- First to use the IBM Floating Point Architecture (today’s standard)
- First to use nine track magnetic tape
- and more…
Please note: The pictures are representative of the condition of the core you will receive.