PDP-1

The PDP-1 (Programmed Data Processor-1) was the first computer in Digital Equipment Corporation's PDP series and was first produced in 1959. It is famous for being the computer most important in the creation of hacker culture at MIT, BBN and elsewhere. The PDP-1 was also the original hardware for playing history's first game on a minicomputer, Steve Russell's Spacewar!.

Description

The PDP-1 used an 18-bit word size and had 4096 words as standard main memory (equivalent to 9,216 eight-bit bytes, though the system actually used six-bit bytes), upgradable to 7004655360000000000♠65536 words. The magnetic core memory's cycle time was 5 microseconds (corresponding roughly to a "clock speed" of 200 kilohertz); consequently most arithmetic instructions took 10 microseconds (100,000 operations per second) because they used two memory cycles: one for the instruction, one for the operand data fetch. Signed numbers were represented in one's complement. The PDP-1 had computing power roughly equivalent to a 1996 pocket organizer and a little less memory.