HP 91


Scientific Calculator

"Introduced on March 1 1976, this was the tenth small electronic calculator sold by HP - but the first one too big to be considered a "handheld". HP called it a "Scientific Portable Printing Calculator" to distinguish it from the smaller models and from their much bigger desktop models. It introduced HP's third family of calculators after the original Classic family and the small Woodstock models, the Topcat family... As befits a top cat, the HP-91 codename was "Felix"" Wlodek Mier-Jedrzejowicz.
Source: MoHPC - The Museum of HP Calculators

X-Number World