'Starting in 1967, a breed of computers now categorized as minis appeared. By 1972, there were several dozen manufacturers making such machines, and they had reached such a degree of uniformity that they can be described as follows --

1. Their Central Processing Units (CPUs) (sold) for between $3,000 and $20,000 2. Their word length (was) either 12 or 16 bits (most often 16) 3. Their main frames measured 19 x 11 x 21 inches (usually designed to be rack-mounted) 4. Their internal operating speeds (were) from 1 to 4 microseconds per full word addition 5. They had markedly similar instruction sets, particularly in their schemes for addressing large amounts of core storage, ranging from 2048 to 65,536 words, within the constraint of their short word length 6. Some of them offered microprogramming capability through the addition of electronically alterable read-only storage (from the first paragraph of the book)