A major advance in the PDP-11 design was Digital's Unibus, which supported all peripherals through memory mapping.

The PDP-11 supported hardware interrupts at four priority levels.

The PDP-11 / 34a supported a fast floating-point option, and the 11 / 34c supported a cache memory option.

* PDP-11 / 44 — Replacement for the 11 / 45 and 11 / 70 that supported optional cache memory and floating-point processor, and included a sophisticated serial console interface and support for 4 MB of physical memory.

* PDP-11 / 03 ( also known as the LSI-11 / 03 ) — The first LSI PDP-11, this system used a chipset from Western Digital and supported 60 kB of memory.

* PDP-11 / 68 — A follow-on to the PDP-11 / 60 that would have supported 4 MB of physical memory.

The operating system and utilities were to run on the entire line of PDP-11 platforms, from the very small systems up through the PDP-11 / 70 which had memory-mapping hardware and supported up to 4 MB of memory.

In 1973 memory management support was included in RSTS ( now RSTS / E ) for the newer DEC PDP-11 / 40 and PDP-11 / 45 minicomputers ( the PDP-11 / 20 was only supported under RSTS-11 ).

System III supported the DEC PDP-11 and VAX computers.

The PDP-11 / 44 was the first low ( er )- cost replacement for the PDP-11 / 70: it had a Unibus and not a Massbus but featured the same 22 bit addressing modes and supported Separated I & D.

The PDP-11 had several uniquely innovative features, and was easier to program than its predecessors with its use of general registers.

It is commonly stated that the C programming language took advantage of several low-level PDP-11 – dependent programming features, albeit not originally by design.

For several years, Mentec produced new PDP-11 processors.

The PDP-11 processors tended to fall into several natural groups depending on the original design upon which they are based and which I / O bus they used.

Other than that, Digital Equipment Corporation created several operating systems for its 16-bit PDP-11 class machines, including the simple RT-11 system, the time-sharing RSTS operating systems, and the RSX-11 family of real-time operating systems, and the VMS system for the 32-bit VAX computer.

It was based on several Digital Equipment Corporation operating systems, mostly for the PDP-11 architecture.

Because of its low cost, the TU58 was fitted to several different systems ( including the VT103, PDP-11 / 24 and / 44 and the VAX-11 / 730 and / 750 ) as a DEC-standard device for software product distribution, and for loading diagnostic programs and microcode.

The Unibus was the earliest of several computer bus technologies used with PDP-11 and early VAX systems manufactured by the Digital Equipment Corporation ( DEC ) of Maynard, Massachusetts.

DATATRIEVE is a database query and report writer tool that runs on OpenVMS operating system as well as several PDP-11 operating systems.

Bell Labs developed several variants of V6, including the stripped-down MINI-UNIX for low-end PDP-11 models, LSI-UNIX or LSX for the LSI-11, and the real-time operating system UNIX / RT, which merged V6 Unix and the earlier MERT hypervisor.

Early implementations were for the DEC PDP-7 and PDP-11 minicomputers using early Unix, and Honeywell 36-bit mainframes running the operating system GCOS.

RT-11 provided a practical real-time operating system in minimal memory, allowing the PDP-11 to continue Digital's critical role as a computer supplier for embedded systems.

* The DOS operating system for DEC PDP-11 minicomputers.

PDP-10 computers running the TOPS-10 operating system were labeled DECsystem-10 as a way of differentiating them from the PDP-11.

Design features of the PDP-11 influenced the design of microprocessors such as the Motorola 68000 ; design features of its operating systems, as well as other operating systems from Digital Equipment, influenced the design of other operating systems such as CP / M and hence also MS-DOS.

A four processor system was maintained by the RSX-11 operating system development team for testing and a uniprocessor system served PDP-11 engineering for general purpose timesharing.

Several operating systems were available for the PDP-11

In 1971 the developers wanted to get a PDP-11 for further work on the operating system.

UCSD Pascal was developed at The University of California, San Diego Institute for Information Systems in 1978 to provide students with a common operating system that could run on any of the then available microcomputers as well as campus DEC PDP-11 minicomputers.

Microsoft's first operating system, MDOS / MIDAS, was designed along many of the PDP-11 features, but for microprocessor based systems.

RSX-11 is a family of real-time operating systems mainly for PDP-11 computers created by Digital Equipment Corporation ( DEC ), common in the late 1970s and early 1980s.

Garth Wolfendale was the project leader for RSX-11D from 1972 – 1976 and led the redesign and commercial release of the operating system as well as adding support for the 22-bit PDP-11 / 70 system.

* RSX-11M-Plus — a much extended version of RSX-11M, originally designed to support the multi-processor PDP-11 / 74, a computer that was never released, but also used widely as a standard operating system on the PDP-11 / 70.

* RSX-20F — PDP-11 / 40 front end processor operating system for the DEC KL10 processor.

*" My first operating system project was to build a real-time system called RSX-11M that ran on Digital's PDP-11 16-bit series of minicomputers.

Both RSTS and Unix were time-sharing systems available to educational institutions at little or no cost, and these PDP-11 systems were destined to be the " sandbox " for a rising generation of engineers and computer scientists.

The Nova ’ s biggest competition was from the new DEC PDP-11 computer series, and to a lesser extent the older DEC PDP-8 systems.

MUMPS was developed with the support of a government research grant, and so MUMPS was released to the public domain ( no longer a requirement for grants ), and was soon ported to a number of other systems including the popular DEC PDP-8, the Data General Nova and the DEC PDP-11 and the Artronix PC12 minicomputer.

The MACSS team drew heavily on the influence of minicomputer processor design, such as the PDP-11 and VAX systems, which were similarly microcoded.

; PDP-11: The archetypal minicomputer ; a 16-bit machine and another commercial success for DEC. ( Also the LSI-11, primarily for embedded systems ).

Higher-performance members of the PDP-11 family, starting with the PDP-11 / 45 Unibus and 11 / 83 Q-bus systems, departed from the single-bus approach.

Later PDP-11 Unibus systems were designed to use similar Q-Bus processor cards, using a Unibus adapter to support existing Unibus peripherals, sometimes with a special memory bus for improved speed.

Other PDP-11 operating systems such as RSTS / E had their own distinctive patterns in the console lights.

The deprecation of type codes ( and creator codes ) over the older extension system, popularised by PDP-11 systems ( RT-11, RSX-11, etc.