From LQWiki

PDP-1 -- The first in a series of mini-computers built by the Digital Equipment Corporation (DEC). These computers were about the size of a refrigerator - hence 'mini' and had RAM memory in the 4-16 Kb range. Unix was originally written in assembly language for a PDP-7.

--Frobinson2004 10:07, Dec 16, 2005 (EST)