DEC began small by making printed circuit modules, with Olsen insisting that the new company’s products be made with the new and expensive transistors. In 1958 their first products were shipped, the Digital Laboratory Modules and Digital Systems Modules. After one year the company had sold $94,000 worth of logic modules for memory testing.

Olsen realised that many of the functions being performed by mainframes could be done by smaller computers, and set out to produce them. So as to seem less threatening to the computing giants, DEC’s first computer came out in 1959 under the name Programmed Data Processor (PDP-1), for a price from $125,000 to $150,000. It was the first commercial machine that used transistors rather than vacuum tubes. After slow sales, DEC received an order for 15 PDP-1 units form International Telephone and Telegraph (ITT) to control their message switching systems. After five years in business, DEC reported sales of $6.5 million and net profits of $807,000.

The 1966 release of the PDP-8 was very successful, and it was comparitively cheap, at $18 000. When one of DEC's salesmen took the small computer to the UK, he compared it with the new 'mini-skirt' and the phrase 'mini' computer was born. DEC's next triumph was the PDP-11, which was simple to use and hard larger memory and more processing power. The company also worked on networking solutions, the DECnet, but this was never a success.