The ORDVAC or Ordnance Discrete Variable Automatic Computer, an early computer built by the University of Illinois for the Ballistic Research Laboratory at Aberdeen Proving Ground, was based on the Institute for Advanced Study (IAS) architecture developed by John von Neumann.

As with other computers of its era, it was a one of a kind machine that could not exchange programs with other computers (even other IAS machines). J. P. Nash of the University of Illinois was a developer of both the ORDVAC and of the university's own, similar, ILLIAC.

External link

• ORDVAC programmer's manual (http://www.bitsavers.org/pdf/ordvac/ORDVAC_programming_Oct56.pdf) (PDF)