AMD Am2900

Am2900 is a family of integrated circuits (ICs) created in 1975 by Advanced Micro Devices (AMD). They were constructed with bipolar devices, in a bit-slice topology, and were designed to be used as modular components each representing a different aspect of a computer control unit (CCU). By using a bit slicing technique, Am2900 family was able to implement a CCU with data, addresses, and instructions to be any multiple of 4-bits by multiplying the number of ICs. One major problem with this modular technique was it required a larger amount of ICs to implement what could be done on a single CPU IC. The Am2901 chip was the arithmetic-logic unit (ALU), and the "core" of the series. It could count using 4 bits and implement binary operations as well as various bit-shifting operations.

Computers made with Am2900-family chips

There are probably many more, but here are some known machines using these parts:

• Data General Nova 4, which obtained 16-bit word width using four Am2901 ALU in parallel; one of the boards had 15 Am2901 ALUs on it.
• Digital Equipment Corporation (DEC) PDP-11/34 and 11/44 floating-point options (FP11-A and FP11-F, respectively)
• The Xerox Dandelion, the machine used in the Xerox Star and Xerox 1108 Lisp machine
• Several models of the GEC 4000 series minicomputers: 4060, 4150, 4160 (four Am2901 each, 16-bit ALU), and 4090 and all 418x and 419x systems......
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