HP-34C


The HP-34C continuous memory calculator was an advanced scientific programmable calculator, produced between 1979 and 1983

Features

Root-finding and integration

Significant to the HP-34C calculator was the capability for integration and root-finding. Integration and root-finding worked by having the user input a formula as a program. Multiple roots are found using the technique of first finding a root, then dividing the equation by, thus driving the solution of the equation away from the root at that point. This technique for multiple root-finding is referred to as "deflation". The user would usually programmatically recall the root value from a storage register to improve its precision.

Programming

The common method of converting registers to program memory allowed the calculator a maximum of 210 program steps. Programming features such as indirect jumps provided substantial capability to the calculator's programmer.
The HP-34C shipped with an "applications" manual that included two games. This made the calculator probably one of the first pocket game computers ever invented. The winner was announced via calculator spelling by turning the display upside down and the words BLISS or I'LOSE were displayed. A game of blackjack was easily programmable by converting some of the registers to lines of program.

Pedigree

The calculator was superseded, in 1982, by the HP-15C.
Although it is argued the HP-41C was a replacement for the HP-34C, they were in fact differentiated as much by price as by functionality and performance. This price difference allowed those with economic constraints to still buy a high-end HP scientific programmable within a reasonable cost. As such they were sold side-by-side for a number of years.

Design

The HP-34C came in a number of variants, such as plastic- and metal-keyboard versions and those with soldered vs pressure-mounted circuitry.