HP-71B
| Industry | Computer hardware |
|---|---|
| Founded | January 1, 1939 |
| Products | HP-71B pocket computer |
The HP-71B was a portable computing device programmable via BASIC, manufactured by Hewlett-Packard between 1984 and 1989.
Description
Compared to the earlier HP-75, the HP-71B was more compact and cost-effective. It featured a single-line, 22-character liquid crystal display, contained 64K of system ROM, and provided 17.5K of memory for user programs. The unit retailed at an MSRP of US$595 (equivalent to roughly US$ today) and could be powered by four AAA batteries or an AC power adapter. Expansion was facilitated through four plug-in ports designed for ROM-based software or additional memory modules. Optional peripherals included a magnetic card reader and an HP-IL interface (model HP 82401A), enabling connections to printers, storage devices, and test instruments.
The HP-71B was notable as the first handheld device to adopt the IEEE 854-1987 standard for radix-independent floating-point arithmetic. Its programming capabilities encompassed features such as a real-time clock, programmable timers, support for subroutines with parameter passing, and recursive functions. It marked HP's initial use of the Saturn processor, which subsequently powered the widely recognized HP-48 series and other HP calculators.
Although the magnetic card reader could handle HP-75 cards storing two tracks of 650 bytes each, its limited storage capacity led to lower popularity. For more substantial data storage, HP-IL peripherals like the battery-operated 82161A cassette drive or the 9114A diskette drive were available, albeit larger than the HP-71B itself. Additionally, third-party memory expansion modules were produced for use in the card reader slot.
Other third-party enhancements included a bar code wand and application-specific ROMs compatible with the memory expansion ports. A notable implementation combined a bar code wand with custom software for data gathering by the British Department of Health and Social Security (DHSS).
Distinct from models such as the HP-75 or HP-41, the HP-71B could operate as a device within an HP-IL loop managed by another controller, allowing multiple units to interconnect or share peripheral devices. Utilizing an HP 82402 Dual HP-IL controller enabled one HP-71B to interface with two separate HP-IL loops simultaneously—serving as controller on one loop while acting as a device on the other.
An optional plug-in ROM module provided compatibility with software written for the HP-41 series by emulating that calculator at approximately five times its original processing speed.
Internal Design Specification
A unique feature of the HP-71B was Hewlett-Packard’s public release of several Internal Design Specification (IDS) documents that thoroughly described the device’s engineering details. Four IDS volumes covered the software embedded in the 71B’s ROM, including full assembly language source code alongside comprehensive design notes. Additional IDS documents detailed hardware components, the Forth/Assembler add-in ROM, and the HP-IL controller add-in module.
External links
- HP-71B at the MoHPC
- HP Journal, July 1984 Special issue focused on HP-71B design and packaging (featuring exploded views)
- HP-71B images on MyCalcDB (a database dedicated to pocket calculators from the 1970s and 1980s)
- Comprehensive HP-71B information in the MoHPC forum
- Official HP-71 Reference Manual