HP-97
| Industry | Electronics, Computer hardware |
|---|---|
| Founded | January 1, 1939 in Palo Alto, California, United States |
| Products | HP-67 calculator, HP-97 calculator |
| Website | www |
The HP-67 is a handheld calculator programmable via magnetic cards, introduced by Hewlett-Packard in 1976 with a retail price of $450. A complementary desktop variant equipped with an integrated thermal printer was marketed as the HP-97, priced at $750. Together, these units are commonly referred to as the HP-67/97 series.
Positioned as the next generation following the HP-65, the HP-67/97 models utilized the "20-series" architecture (HP-25, HP-19C, among others) that had debuted a year prior. Both devices share identical functionality and support interchangeable magnetic card programs.
Features
The HP-67/97 provide an extensive array of scientific, statistical, and engineering capabilities, encompassing trigonometric calculations, logarithms, exponentials, coordinate transformations, averages, and standard deviation computations.
Memory consists of 224 eight-bit words—offering two additional bits per word compared to the HP-65—which enables storage of multi-keystroke instructions within a single memory cell through "fully merged keycodes." Programming features include 20 labels, subroutines nested up to three levels deep, four flag registers, eight comparison operations, as well as sophisticated indexing and looping controls.
Their 15-digit numeric display surpasses earlier models in width, with the decimal point occupying a dedicated digit space. The HP-67’s keyboard supports up to four functions per key accessed via "f", "g", and "h" prefix keys marked in gold, blue, and black respectively. In contrast, the HP-97 features larger keys with two functions each. Software routines handle keycode translation and replicate the HP-97’s printing functionality on the HP-67’s screen during magnetic card exchange.
Power for the HP-67 is supplied by three AA-sized nickel-cadmium rechargeable batteries. The HP-97 requires a bulkier battery pack and accompanying charger to meet the energy demands of its thermal printing mechanism.
Memory and programming
Within the 26-register data memory structure, the initial ten registers ("primary registers") are directly accessible. An additional ten constitute an alternate register set, while the last six are reachable through user-assigned keys A-E combined with an index register. This indexing system treats all 26 registers as a unified array. Since data memory is volatile, all stored information and programs are erased when power is discontinued. The alternate register set facilitates statistical operations.
The built-in magnetic card reader/writer allows users to save programs and data as well as merge content from multiple cards. This magnetic card format was later adopted by the HP-41C, which provided backward compatibility via software emulation. Hewlett-Packard offered a collection of pre-recorded magnetic card programs tailored for fields such as surveying, medicine, civil engineering, and electrical engineering. Write protection on cards could be implemented by physically modifying one corner.
Beyond official support from HP, a dedicated user group known as PPC produced the PPC Journal and developed add-ons like the "Blackbox," which enabled limited pseudo-alphanumeric display capabilities.
An alternate version equipped with an extra rear-facing display—the EduCALC 67 GD—was produced by Educational Calculator Devices.
HP-97S
In 1977, Hewlett-Packard released the HP-97S, an upgraded desktop model incorporating an additional parallel I/O interface (consisting of 40 lines for ten 4-bit BCD digits plus five control signals) intended for interfacing with external equipment. This model was offered at a price of $1,375.