The Maniac II system

The operating system to be described in this paper serves the Maniac II computer and about 40 users. Maniac II is a research computer and undergoes more or less continual modification and improvement. In its eleven-year life, it has grown in speed from 10,000 instructions per second to 100,000, in vocabulary from 80 instructions to about 300, and in memory size from 12,000 words to 80,000 (changing from half- to full-word instructions in the process). It runs in an open shop. It is in operation about 130 hours a week with only about 50 hours being handled by professional machine operators. At least 8 hours a week are devoted to new construction. On-line input/output equipment consists of console typewriter, scope display, paper tape reader and punch, card reader, line printer, and magnetic tapes. Off-line there are two magnetic tape driven Cal-Comp plotters, an IBM 047 keypunch, and the modified Flexowriters referred to below.