Joseph Weisbecker’s System 00

Unlike most images in this gallery, the machine pictured below contains no microprocessor chip!

In 1971, Joseph Weisbecker created this prototype of what would eventually be refined into RCA’s COSMAC series of microprocessors. The prototype is called System 00 in its manual. These photos are by Z. Stachniak, courtesy of the David Sarnoff Library, used here by permission. More images related to COSMAC history may be found on Stachniak’s website, which supplements information found in his book “Inventing the PC: The MCM/70 Story.”

System 00 front panel, with a hex keypad and rows of toggle switches, buttons, and lights.

The System 00 manual, now available online from here, provides the following specifications:

  • 1024 bytes memory installed, up to 64K permitted
  • sixteen 16-bit registers
  • 8-bit word length
  • 1.6 microseconds per instruction (minimum), up to 300K operations per second
  • 16 switches for data or program entry in hexadecimal
  • 200KB per second asynchronous I/O
  • X-Y-Z oscilloscope display output
  • other peripherals include a hand-fed 3x5 inch punch card reader and a “yes/no” switchbox that provided two input signals to simplify use for programs such as games

The manual also makes it clear that “All logic circuits utilize standard 7400 series TTL chips.”

Perspective view of the System 00 prototype computer.

System 00 currently resides at The College of New Jersey as part of the Sarnoff Collection, where it is referred to as “Personal Computer Model 00.” Their page for the artifact may be found here.

Other images and more information about this machine can be found on Herb Johnson’s retrotechnology website.

© Dave Ruske 2001-2017, except where noted