Daves Old Computers - Osborne

In 1981, Adam Osborne produced what is generally considered to be the first truly portable computer. Although technically, there were a few other "portable" machines which came before it (for example, the IBM 5100, which cost $20,000, and ran an IBM proprietary system), the Osborne was the first portable CP/M system, and the first "affordable" portable computer. It was therefore the first portable computer to achieve widespread use.

The most notable feature of the Osborne is the small (5") internal monitor, which could display only 52 columns at a time. Many people found this to be too difficult to use, and "Osborne clones" with bigger screens such as the Kaypro soon appeared on the market.

The Osborne-1 appeared in two distinct releases, both of which are shown here. The first edition is slightly smaller, and has keyboard latches on the side. The second edition is much sturdier, slightly larger and has the keybaord latches on the top.

The Osborne-1s were donated by Dan Lanciani and Richard Parsons..
The Osborne-1As were donated by Bob Maxwell and Ralph Curtis.

Click any photo to view a large high-resolution image.

Osborne-1 (first edition)

The Osborne-1 - Note the full sized 5.25" diskette drives, and the tiny video display. The keyboard is separate from the main unit, and clips onto the front of the machine for storage and travel. It was designed such that the machine could sit up on the keyboard (as shown) when in use.

Closeup view of the Osborne-1 front panel and keyboard.

Back of the Osborne-1. Note that this edition has a permanently attached power cord. A velcro cover holds it in place while traveling.

Here the keyboard is clipped into place on the front of the machine, and it is ready for travel.

Here are views from the Top and Bottom.

Osborne-1a (second edition)

This is the second edition of the Osborne-1, produced about a year after the original version shown above. Note that the case is appears to be much stronger, and the machine is slightly larger. Internally, the two machines are virtually identical.

Closeup view of the Osborne-1s front panel and keyboard.

Back of the Osborne-1s. Inside the hatch are the model name plate, power connector, switch and fuse, as well as room to store the coiled up power cord.

Here is the Osborne-1a closed up and ready to be transported.

Here are views from the Top and Bottom.

As you can see here, the angle of the keyboard prevents the machine from sitting straight up when closed.

Here is the inside of an Osborne-1. Here is a closeup of mainboard.

Here are some original Osborne-1 manuals.

Upper left hand is the Osborne-1 user/reference manual.
Upper right hand is the Osborne-1A user/reference manual.

And here are some original distibution diskettes which came with these machines.

The Osborne-2 "Executive" is an updated Osborne-1A. Packaged in a case nearly identical to the 1A, the most notable feature is the larger 7" screen. This was accomplished by using 1/2 disk drives occupying only one side of the machine for both drives. This allowed the screen to be offset to one side and enlarged. On the back we see another addition - a cooling fan under the handle. Internal improvements include more RAM and native 80 column video capability. It is reported that the announcement of the Executive some time before it was ready to ship virtually halted sales of the Osborne-1 and contributed greatly to the companies demise.

The Osborne-4 "Vixen" is the last machine produced by Osborne, in fact this machine was still in development when the company folded (Like the Executive, early announcement of the Vixen causes major problems for Osborne). The company was reopened briefly in 1985 and a few of these machines were sold.

This is the "cutest" Osborne - it is much smaller than the Osborne-1/2, yet has the larger (7") screen. The keyboard is permanently attached, and folds down to serve as a riser for the front of the machine.

Here is a view of the back, and here it is closed.

1981 Osborne advertisement (108k JPG)
1983 Osborne advertisement (47k JPG)
An Industry Challange: 1981 KiloBaud artical by Adam Osborne (1.3M PDF)
Osborne-1 Ad with specs. (38k JPG)
Osborne-1 At a Glance" (38k JPG)
Osborne-1 Technical Manual (19M)
CP/M version 2.2 Manual (0.5M PDF)
Z80 CPU Technical Manual (5M PDF)

Z80-CP/M emulator
Z80-CP/M simulator - boots CP/M

Back to Old Computers

Copyright 2004-2005 Dave Dunfield.