The Hewlett-Packard HP-9825A third-generation, desktop, programmable calculator was introduced in 1976. It had a full QWERTY keyboard and a 32-digit LED display. It had a 248K mini-cartridge tape drive, a 16-character thermal printer, and three I/O expansion slots at the back. It could also be connected to external eight-inch floppy disk drives. The 9825A came with 6.8K RAM, which was expandable to 31.4K. The calculator also had four ROM slots. It has a 16-bit CPU which consists of three main LSI chips (Math Unit, I/O Processor, and Main Processor Control).

The 9825A had a live keyboard, which allowed users to continue to use the keyboard during program operation, rather than disabling the keyboard as was standard. For the first time this allowed the user to examine and change program variables, perform complex calculations, call subroutines, and record and list programs while the calculator was performing other operations.

The HP-9825A was the first machine to use Hewlett-Packard's HPL (High-level Programming Language). It was a successor to the programming language used on the previous HP-9820A. HPL was similar to BASIC, and is often referred to as BASIC with vowels.

Due to the language used at the time of its release, this machine was called a programmable calculator despite its capabilities. In the Hewlett-Packard Journal in June 1976 it called it a "powerful medium-priced desk-top programmable calculator with many features previously found only on minicomputers". It went on to say the calculator "is designed primarily for use in the fields of engineering, research and statistics. The new calculator's speed, interfacing abilities and computer-like features make it particularly well suited for use as the controller of an instrument system, for pilot process control applications, for remote data collection, and for production control. It can also be used as a powerful stand-alone computing tool."

Our two units were very kindly donated by QinetiQ from Great Malvern which was kindly arranged for us by Michael Hamer of QinnetiQ.

Manufacturer: Hewlett-Packard
Date: 1976

This exhibit has a reference ID of CH4928. Please quote this reference ID in any communication with the Centre for Computing History.

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