PDP-9

PDP-9
Manufacturer:	Digital Equipment Corporation
Year First Shipped:	1966
Form Factor:	minicomputer
Word Size:	18 bits
Logic Type:	PNP Transistor FLIP CHIPs
Design Type:	microcoded
Memory Speed:	1 μsec
Physical Address Size:	15 bits (32K words)
Virtual Address Size:	13 bits (direct), 15 bits (extended)
Memory Management:	bounds register
Predecessor(s):	PDP-7
Successor(s):	PDP-15
Price:	US$30K (8KW system)

The PDP-9 was DEC's fourth 18-bit computer, and the first DEC CPU to use microcode. A little over 400 were built.

Its principal intended use was for real-time systems, including data recording and process control. A variety of models were offered; the basic system provided 8K words of core memory, and the PDP-9/L was a cost-reduced system with cheaper peripherals and 4KW of memory.

Instructions had a 4-bit opcode, 1 bit of indirect, and 13 bits of address. It was a load-store architecture, with a single accumulator. Multiply/divide was a hardware option, the KE09A, which also performed shifting.

Use of more than 8KW of main memory required the Memory Extension Control, KG09A. A memory management option, the KX09A, which included a boundary register to set the boundary between protected and un-protected memory, and two modes for the CPU, was also available.

A large range of peripherals were available, including DECtape (via the TC02 controller), magnetic tape (via the TC59), drum (RM09 controller) and fixed-head disk (RB09).

Further Reading

(All available online through BitSavers.)

• PDP-9 User Handbook

=External links

• PDP-9 - Has manuals for KE09, KF09, RF09