PDP-8/A

PDP-8/A
PDP-8/A-400
Manufacturer:	DEC
Architecture:	PDP-8
Year Introduced:	1976
Form Factor:	minicomputer
Word Size:	12
Logic Type:	TTL
Clock Speed:	666KHz
Memory Speed:	2.3 µseconds
Physical Address Size:	32KW (requires optional KM8-A)
Virtual Address Size:	4KW
Memory Management:	bank selection, CPU mode
Bus Architecture:	OMNIBUS
Operating System:	OS/8, TSS/8
Predecessor(s):	PDP-8/E
Successor(s):	None
Price:	US$2.6K (CPU. 4KW memory, Operator's Panel)

The PDP-8/A was DEC's last non-microprocessor PDP-8. The KK8-A CPU was a single hex board (M8315), which plugged into an OMNIBUS backplane. It supported both core main memory (MM8-AA, H219A/G649; and MM8-AB, H219B/G650) and semiconductor (MS8-A, M8311).

There were a number of options available for use with the -8/A, including:

• KM8-A Extended Option - main memory extension, time-sharing control, bootstrap ROM, etc
• DKC8-AA - front panel control, real-time clock, asynchronous serial line interface, parallel port, etc
• FPP8/A Floating Point Processor

The -8/A could use either an Operator's Panel, or a KC8-AA Programmer's Panel (similar to the KY11-LB); the latter required the DKC8-AA.

The -8/A came either as a kit of boards, or as a complete system including a chassis, power supply and backplane; in the latter form, there was a list of different configurations.

Eternal links

• PDP-8/A - documentation at Bitsavers
• PDP-8/A Miniprocessor Users Manual (EK-8A002-MM-002)
• PDP-8 Summary of Models and Options - What is a PDP-8/A?