The 74181 is a 4-bit slice arithmetic logic unit (ALU), implemented as a 7400 series TTL integrated circuit. Introduced by Texas Instruments in February 1970,[1] it was the first complete ALU on a single chip.[2] It was used as the arithmetic/logic core in the CPUs of many historically significant minicomputers and other devices.
The 74181 represents an evolutionary step between the CPUs of the 1960s, which were constructed using discrete logic gates, and today's single-chip microprocessor CPUs. Although no longer used in commercial products, the 74181 is still referenced in computer organization textbooks and technical papers. It is also sometimes used in "hands-on" college courses to train future computer architects.
- ^ Höltgen, Stefan, ed. (2017). Logik, Informationstheorie [Logic, Information Theory] (in German). De Gruyter. p. 115. ISBN 9783110477504 – via Google Books.
- ^ Daniel P. Sieworek; C. Gordon Bell; Allen Newell. "Chapter 6: Structure". Computer Structures: Principles and Examples (PDF). p. 63.
The earliest and most famous chip, the 74181 arithmetic logic unit (ALU), provided up to 32 functions of two 4-bit variables.