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1980s Computers Explanation of terms

The HP-71B



Hewlett-Packard (US)



Date Launched

February 1984


Approx £300? ($525 in the USA)

Microprocessor type

HP Saturn @ 2? MHz
(A CMOS CPU designed for advanced calculators, with 64-bit data registers and 20-bit addressing. Data was handled in 4-bit nybbles and arithmetic could be performed in binary coded decimal. Transferring data four bits at a time greatly reduced the number of interconnecting tracks on the circuit board and helped to keep the size down.)

ROM size

64 kilobytes
Four expansion ports could hold up to an additional 64KB of ROM each.

Standard RAM

16 kilobytes available to user plus 1.5KB for the display

Maximum RAM

32 kilobytes for user (4KB in each of the expansion ports)
The theoretical address space was 512 kilobytes.

Keyboard type

Calculator style with separate QWERTY and numeric areas

Supplied language

Powerful BASIC. New commands could be defined and then used like built-in commands.

Text resolution

1 line of 22 characters, which acted as a window onto a 5 line by 96 character screen.

Graphics resolution

132 x 8 pixels

Colours available

Black on grey

Example Screenshot

HP-71B display
The HP-71B's single-line display was an improvement on that of a calculator but still rather limiting for a general-purpose computer.


Single channel, variable pitch and duration

Cassette load speed

No cassette interface but the HP-IL interface could transfer data at 5000 bytes per second.
A magnetic card reader (1300 bytes per card) could be plugged into an expansion port on the rear.

Dimensions (mm)
Weight (grams)

192 x 96 x 25

Special features

Battery powered, running off 4 AAA cells.
Real-time clock.
Wide range of peripherals available including ink-jet printer, cassette tape unit, floppy disk drive, RS-232 serial port, and modem, all connecting via the optional HP-IL interface.

Good points

Pocket-sized (or at least briefcase-sized) yet as powerful as some desktop computers of the time.
Typical HP high build quality.
The common BASIC commands were printed on the keyboard and could be entered as shifted keys, reducing the amount of typing on the small keyboard.

Bad points

The HP-71B was much pricier than other pocket computers from Casio and Sharp, which tended to cost around £100 to £200, though it was a far more versatile machine.

How successful?

Very popular with those who used it, and still worth about £100 secondhand today.


The HP-71B was an elegantly styled and very desirable machine in 1984. It could operate as either an advanced scientific calculator, processing expressions immediately, or as a BASIC-programmable computer, to give maximum flexibility in use.
It was designed as a general-purpose calculating/processing device for scientists and engineers.
The HP-71B included a rudimentary operating system which allowed named files in RAM to be copied and deleted, and even permitted partitioning of RAM into independent areas. A system password could be set and files could be made read-only or protected from modification.
Software applications on plug-in ROM could be added, including a text processor.
The Hewlett-Packard Interface Loop (HP-IL) was a multi-purpose serial interface for connecting to a wide variety of peripherals or scientific instruments, so that the HP-71B could be used as a portable data-logger. Up to 930 devices could be connected to one HP-IL loop!

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