60-bit computing

In computer architecture, 60-bit integers, memory addresses, or other data units are those that are 60 bits wide. Also, 60-bit central processing unit (CPU) and arithmetic logic unit (ALU) architectures are those that are based on registers, address buses, or data buses of that size.

60-bit CDC 6600 introduced in 1964

A 60-bit word is typically used for high-precision floating-point calculations; it can also store 10 6-bit characters.^[1]

Examples

The only widely-used computers with 60-bit words were produced by Control Data Corporation (CDC),^[2] including the CDC 6000 series,^[3] the CDC 7600, and the CDC Cyber 70 and 170 series.^[4] Though the addressable unit was the 60-bit word, instructions were either 15 or 30 bits.^[3]

Early design documents for the IBM 7030 Stretch tentatively specified its word length as 60 bits; the final design used 64.^[5]

Emulator

Museum examples of 60-bit CDC machines exist. There also exists an emulator for the series which will simulate the CDC 60-bit machines on commodity hardware and operating systems.^[4]