A series of large, 36-bit word mainframe-like systems built by DEC. They were basically a re-implementation of the earlier PDP-6 architecture, whose hardware engineering had been a failure. (The machines were so similar at the programming level that PDP-6 object code could run on a PDP-10.)
PDP-10s were very important machines on the early ARPANET and Internet, being one of the few (relatively!) cheaply available machines which could run a full NCP and later TCP/IP stack as a multi-user environment at the time.
They still have a large following today, due in part to the innovative time-sharing operating systems written for them (especially ITS). There are several good simulators available, notably SIMH and KLH10.
Like most mainframes, PDP-10's were composed of a number of separate free-standing units of various types (CPUs, main memory, etc), connected together with busses carried in point-point cables. Systems could be upgraded by adding additional units, or replacing existing units with enhanced successors.
DEC-10's supported a number of different busses: there are different types of bus for main memory (the PDP-10 Memory Bus), and peripherals. On the KA10 and KI10 models, the PDP-10 I/O Bus was provided for the latter; it allowed peripherals to interrupt the CPU, and supported programmed I/O (including block transfers).
On the KL10, an optional DIA20 In/Out Bus Controller could also be attached, to provide a KA10/KI10 compatible I/O bus. However, by the KL10 era, most low-speed peripherals were connected to front end computers, always DEC minicomputers, which allowed the production of PDP-10-specific versions of all those devices to be dispensed with.
In the KA10 and KI10, high-speed mass storage device controllers generally connected to both i) a channel, the DF10 Data Channel, which was attached to an external memory bus, and ii) the PDP-10 I/O Bus. The CPU controlled the channel via the device controller. This setup was used to connect mass storage controllers, such as:
- RP10 disk controller - RP01, RP02 and RP03 disk drives
- RC10 disk/drum system - RD10 fixed-head disk, RM10B drum
- TM10 Magnetic Tape Control - TU10 and others
The RH10 MASSBUS controller (which appeared toward the end of the KI10 period), for MASSBUS mass storage devices, was similarly connected (to a DF10 channel, and the I/O bus). On the KL10, up to 8 RH20 MASSBUS controllers, which similarly supported mass storage devices, could be connected to the system.
- TD10 DECtape Control - TU55
- BA10 Hardcopy Control - LP10 line printer, XY10 plotter, CR10 card reader, CP10 card punch
- DC10 asynchronous serial line controller
- DS10 synchronous serial line controller
PDP-10's made use of front end computers from an early stage.
The DA10 Twelve- and Eighteen-Bit Computer Interface, which connected to the I/O bus, allowed a computer such as a PDP-8/I to exchange data with a PDP-10. The DC68A Data Communication System uses a DA10 to communicate with a PDP-8/I which has a DC08 Serial Line Multiplexer to interface with up to 128 asynchronous serial lines.
The DL10, connected to both an external memory bus and the I/O bus, allowed the PDP-10 CPU to control up to four PDP-11's. The DC75 Synchronous Communication Multiplexer uses a DL10 to communicate with a PDP-11/20 which has one or more DS11 Multiple Line Synchronous Interfaces to interface with 8 or more (depending on the configuration) synchronous serial lines.
On the KL10, up to 4 DTE20 Ten-Eleven Interfaces, each of which allowed the connection of one PDP-11, could be attached. (One PDP-11, the 'master', a PDP-11/40, would bootstrap the KL10, including loading the microcode; it could also be used for other 'normal' front end activities, such as driving groups of asynchronous serial lines, providing DECtapes, etc.)
The first three generations of PDP-10's were marketed as the DECsystem-10, running the TOPS-10 operating system; the third was also sold as the DECSYSTEM-20, running TOPS-20. (The varying capitalization was allegedly the result of a trademark infringment suit.)
Two other very important operating systems also ran on PDP-10's: MIT's ITS (a very advanced system, from whence came EMACS, and much more besides), and TENEX, which DEC later turned into TOPS-20. WAITS was created at SAIL and also ran at two other sites.
The 36-bit line was cancelled by DEC many times. In the beginning, the PDP-6 was difficult to manufacture and maintain, and only 23 were sold; it was cancelled not long after its introduction. However, it made a comeback as the PDP-10, which was a success. At the end, the PDP-10's uncertain future allowed a number of small vendors to sell PDP-10 'clones'.
Cancelled DEC projects
- KXF10 "Dolphin", cancelled around 1978.
- KT20 "Minnow", cancelled around 1979.
- KC10 "Jupiter", cancelled 1983.
- Foonly: F-1, F2, F3, F4, F5 (unfinished)
- Systems Concepts: SC-30M, SC-40
- Tymshare: System 26, System 26KL.
- CompuServe: JRG-1 (unfinished)
- XKL: TOAD-1, TOAD-2
- David Conroy: PDP-10/X
- Neil Franklin: (unfinished)
- Rob Doyle: KS10 FPGA
- David Bridgham: KV10 (in progress)
- Angelo Papenhoff: FPDPGA, PDP-6 and KA10 FPGA.
- S W Galley: virtual machine PDP-10
- Megan Gentry: sim10
- Stu Grossman: kx10
- Ken Harrenstien: KLH10
- Eric Smith: (unfinished)
- Daniel Seagraves: e10
- Tim Stark: ts10, MSE
- Bob Supnik: KS10 simulator for SIMH.
- Richard Cornwell: PDP-6, KA10, KI10, and KL10 simulators for SIMH
- Angelo Papenhoff: PDP-6 simulator
- Bruce Baumgart: WAITS reenactment
- Jeff Parsons: PCjs
- Mark Garrett: TITAN
- Paul Nankervis: nankervis-pdp10-js
- PDP-10 Systems
- PDP-10 Processors
- PDP-10 memories
- PDP-10 Peripherals
- DEC indicator panel
- PDP-10 core images
- PDP-10 Interface Manual (DEC-10-HIFB-D) - Covers all the busses
- Bitsavers PDP-10 documents
- PDP-10 - very early brochure
- The Evolution of the DECsystem 10 - CACM paper that covers the evolution from the PDP-6 through the KL10
- Phil's PDP10 Miscellany Page - an incredible collection of stuff
- Twenty Years of 36-bit Computing with Digital 1964-1984
- Life in the Fast AC's - amusing personal history of PDP-10's
- 10periphs - list of PDP-10 peripherals, other stuff
- nocrew's PDP-10 stuff
- PDP-10 Serial Numbers - lists all still-extant PDP-10's
- PDP-10 Models
- PDP-10 Model Information
- PDP-10 I/O Structure
- The DEC PDP-10 Emulation Webpage