On Tue, 16 Oct 2012 19:50:24 -0400, Fred Ridder <docudoc at hotmail.com> wrote:
>The American definition was as a fraction of a foot: >0.013837 (or 1/72.27) to be exact. That works out >to 4.2175 mm. > >But the computer world likes rounder numbers, and the >computer pica is 1/72 of a foot (specifically the >metrically redefined foot of 1959), and that works out >to 4.23333... mm. The latter size, 6 picas per inch, we (typesetters) in 1970 called the "IBM pica", because it was invented by IBM for the MTST (Magnetic Tape Selectric Typewriter), the predecessor of the word processor. I still have both the steel pica sticks we used when specifying for hot-metal (or foundry type) composition in "real picas", and the one with the IBM logo for the MTST... ;-) -- Jeremy H. Griffith, at Omni Systems Inc. <jeremy at omsys.com> http://mif2go.com/
