NCR 500 Computer

The 500 was a development of the Class 390 which had sold to many businesses and the US Military. Introduced in 1967 if became very popular with small to medium businesses.

NCR 500  Machine Code

(This is a link to the Language page)

Booklets

NCR Series 500 (From Data Processing Jan-Feb 1974) 

500 Command the Facts

500 Magnetic Card Concept