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1980s Computers Explanation of terms

The Osborne 1

Osborne 1


Osborne Computer Corporation (US)


Osborne 1

Date Launched

April 1981



Microprocessor type

Zilog Z80A @ 4 MHz

ROM size

Not known

Standard RAM

64 kilobytes

Maximum RAM

64 kilobytes

Keyboard type

Typewriter style with separate numeric pad.

Supplied language

Microsoft BASIC and Compiler Systems BASIC (loaded from disc).

Text resolution

52 X 24 characters on built-in display, as a 'window' onto a 128 x 32 character screen.

Graphics resolution

No graphics

Colours available

Monochrome (blue on black)


None ?

Cassette load speed

Not applicable (built-in disc drives).

Dimensions (mm)
Weight (grams)

500 x 500 x 220 (Approx, closed)

Special features

A complete computer with two 5¼ inch 100 KB disc drives, a 5 inch (diagonal) monitor and a fold-down keyboard in a single portable unit.

Good points

The first genuinely portable desktop computer.
It was supplied with a suite of software including the CP/M operating system, Wordstar word processor and Supercalc spreadsheet.
Since the software package would cost about £800 if bought separately, the Osborne 1 was actually quite a bargain.

Bad points

The Osborne 1 being carriedWeighing 24 pounds it was usually described as 'luggable' rather than portable:

The screen was small and difficult to read. A separate 12 inch monitor could be attached but of course the advantage of portability was then lost.
A battery pack (lasting 2 hours) was extra.

How successful?

As the only self-contained and portable business computer at the time the Osborne 1 sold well, at a rate of 10,000 per month at one point. Sales totalled $70 million in the first year.
In 1982 it was replaced by the Osborne Executive.


The Osborne 1 was intended to be carried to where it was to be used and then plugged into the mains, rather than being used on the move. Remember that in 1981 not many businesses had desktop computers so anyone needing to use a computer in different locations had to take one with them.
The case was designed to fit underneath a standard airline seat and also had a carrying handle, though at 24lbs you would not want to carry it very far by hand.
There were two recesses beneath the disk drives to hold 25 extra floppy disks.
The picture above shows the original design of case. Later versions of the Osborne 1 had a more angular case, as used for the Osborne Executive.

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