What is a PDP-9?

Introduction

Introduced in 1966, the PDP-9 was a 18 bit minicomputer built by Digital (DEC). The machine was a successor to the PDP-7 minicomputer, which it was upwardly compatible with and had roughly double the performance of the earlier machine. The machine could address up to 32KW of core memory.

The PDP-9 was one of the first small/medium sized computers to feature a keyboard/monitor system (a rudimentary for of operating system) which ran on the DECtape storage system.

The PDP-9/L, a compact and lower cost version of the PDP-9 was introduced in 1968. Of the 450 PDP-9s produced, 40 were PDP-9/Ls.

The PDP-9 was replaced by the TTL based PDP-15 in 1969.

Options and Peripherals

Option	Description	Capacity
CPU and memory	PDP-9	4KW – 32KW
CPU options	KE09A EAE, extended arithmetic element
	KG09A memory extension control
	KP09A power fail detection
	KX09A memory protection control
Console	KSR-33 Teletype
Additional terminals	LT09 and KSR-33 Teletypes	1-4 lines
Paper tape	PC09A paper tape reader and punch
Real time clock	integral
Line printer	Type 647E line printer (sixbit ASCII)
	LP09 line printer (sevenbit ASCII)
DECtape	TC02/TU55 DECtape	148KW
Disk	RF09/RS09 fixed head disk	2.1MW
	RB09 fixed head disk	1MW
Magnetic tape	TC59 magnetic tape (9 track only)