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Sol-20 by Processor Technology (1976-79)

Acquired: October 2001
with thanks to John MacPherson

The Sol-20 by Processor Technology is a beautifully designed and visually appealing system and has the proud distinction of being the first commercially mass produced packaged personal computer (looking less like a boxy kit like the Altair 8800 and more like a real computer, ie, a "Terminal Computer" harkening to the slick terminals with integrated keyboards of larger timesharing systems).

Lee Felsenstein has kindly provided the following insight into the Sol (paraphrased):

While I was indeed the sole designer of most of the Sol-20 circuitry and worked hard to manage the circuit board through to manufacture, many others were involved in the building of the Sol. Gordon French was the project manager and the primary mechanical designer (his bridge-quality reinforced sheet metal design set a standard that has rarely been duplicated in personal computers). Bob Marsh designed the power suppy and the audio cassette interface (which I was reluctant to approach). Aram Attarian II and Vern Muhr did much of the heavy lifting, debugging and tech work in the process.

Curator's Note: admire the fine walnut (no, not maple) used in the case, giving the Sol the nickname "old woodsides". Also note that this was the very first full page on a computer system created on the DigiBarn site way back in 2001! We have since acquired several more Sols and will be featuring more detailed photos of those here.

Be sure to check out our special site: Solfest, Processor Tech and the Sol-20 resources at the Digibarn.



Sol 20 with disk drive and monitor


Faux wood disk drive (two 5 1/4'' floppies)
Showing wood side paneling in maple
The sol system
Sol-20 from the front
Sol-20 with the covers off
View of the insides of the Sol
Case covers
Hardware views
Books with the Sol and software cassettes

Digibarn virtual visitor Phil Gilmer writes (Jan 1, 2005):

One note on your Processor Technology SOL-20 page. The sides of the computer were walnut, not maple as stated in your article. There have been more than one article on this.

I myself am the proud possessor of a PT Sol-20 that I built in October 1977. It has beautiful tung-oiled walnut sides. I modified it a long time ago to allow 64KB of memory. I will add that it still works just fine!

Thanks for the great article.

Best Wishes in the New Year!

Another Digibarn virtual visitor writes (Dec 2005):

Your website is, I believe, incorrect on one small point-- the sides of the SOL 20 are not maple but walnut.

Curator: Thanks for that correction, duly noted!

See Also

Solfest! Our page of resources of
Processor Technology and the Sol-20 at the Digibarn & around the web

Know anything about the Sol-20 or Processor Technologies? Contact us!

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