MELCOM 1101

The MELCOM 1101 was the first digital computer of Mitsubishi Electric Corporation completed in 1960. It was designed primarily for scientific and engineering computation. It had features of 33-bit word, static logic, binary serial operation and a stored program. All circuits were implemented with transistors. Approximately 3,500 germanium transistors and 4,000 germanium diodes are used in its logic circuits. A delay-line type magnetic drum with a rotation speed of 3,600 rpm was used for its memory. Its capacity was approximately 4,000 words.

Its input operations, output operations and arithmetic operations were controlled independently. Their simultaneous operations greatly reduced the system processing time. Furthermore, simultaneous operation between instructions of multiplication, division, shift or normalization and those of addition, subtraction or conditional execution reduced the arithmetic operation time.

The machine employed building block architecture, which enabled its functionality to be increased greatly by adding equipment such as an arithmetic accelerator called FLORA or a differential analysis unit called DDA.

This MELCOM 1101 was used at Gakushuin University from 1963 and donated to National Museum of Nature and Science, Tokyo in 1976.