Mainframe Computers

This is an IBM sales photograph of a large mainframe computer. It has two Central Processing Units (CPU). They are on the left, each is 6ft high (Sorry, 1.8 meters high). They are both connected to the four RAM (Random Access Memory) core storage modules, (only three of which are in the photograph), each containing 256 KByte of storage. The total RAM of this duplex configuration was 1 MByte. (That may not seem much to you now, but then it meant 8 million ferro-magnetic toroids (doughnuts), about the size of a "comma" on your keyboard. Each of which was threaded by three wires.)