PDP-11/03

PDP-11/03
Manufacturer:	Digital Equipment Corporation
Architecture:	PDP-11
Year Introduced:	1975
Bus Architecture:	QBUS

PDP-11/03

The PDP-11/03, which initially shipped with the new LSI-11 CPU, marked a major change in the PDP-11 family in two ways:

• it was the first PDP-11 to essentially use a microprocessor (although the LSI-11 chip set was 4 chips, not 1, it was effectively a microprocessor);
• it was the first to use a new system bus, the QBUS, which used fewer lines (thus allowing cards which plugged into QBUS backplanes to have fewer contact fingers), thereby reducing costs.

hampage.hu

Quoting:

1975. With the use of LSI semiconductor technology (the LSI-11 and LSI-11/2 processor), it was a compact implementation of the -11 architecture. It was limited though, to 32KW memory, only one processor operating mode, and limited floating-point instructions (the FIS). Available options: CIS, WCS, EIS/FIS.

The /03 used the new LSI bus, later known as the QBUS, and was aimed at the low-end market, as the successor of the /05. The slowest of the -11s (one third of the 11/20's performance).

A PDP-11/03 was also used as the diagnostic and control unit for the VAX-11/780's CPU; it would bootstrap the system.

External links

• -11/03 - documentation at Bitsavers
  • LSI-11, PDP-11/03 user's manual (EK-LSI11-TM-002)
  • PDP-11/03 engineering drawings
  • The LSI-11 - A System Microcomputer
• LSI-11 Systems Service Manual - Volume III (EK-LSIFS-SV-005)
• A source handbook for Digital Equipment Corporation LSI-11-compatible products