Theo Engel's DDPx16 pages (Honeywell's 16 bit minicomputers)
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  • About the DDPx16 Minicomputers

    This range of computers was originally designed and marketed by the Computer Control Company (3C). The DDP-116 was introduced in 1965, based on technology of and experience with the DDP-124 and it was the first computer on the market using a 16 bit word length and arithmetic. With that, this machine was the start for the coming years of a new phenomenon: low cost computing, based on minicomputers.

    The Computer Control Company became part of Honeywell in 1966, as its Computer Control Division. Also in that year the DDP-516 and the DDP-416 were introduced. In 1969 the H-316 became on the market.

    The DDP-516/416 machines started to use IC-based logic, while the DDP-116 was still using transistor based logic modules. The size of the machines became smaller, but these machines were still heavy: about 115 kg for the basic cabinet. Also the power consumption of about 1 kW was still substantial, but these machines did not need air conditioning anymore. The H316 exploited a much larger scale of integration and really became a minicomputer.

    The DDP-516 and H-316 are the same machines from hardware / software interface point of view. These machines were also quit similar to the DDP-116, except for a few small differences (e.g. the DDP-116 had an index register like the 516/316 but no LDX, STX instructions. The index register on the 116 had to be addressed as memory location 0). The 416 was a downward compatible machine and really lacked a lot of features, which made the machine only useful for process control applications. The 516/416 exploited magnetic core memory with a cycle time of 0,96 musec. The 316 was a slower machine, with 1.6 musec memory.

    The price of a paper tape oriented H-316 machine was somewhere between 12.500 and 15.000 $US and for a DDP-516 at least twice as much.

    The machines were also sold by Philips as P9201 (416), P9202 (516) and P9203 (316) for various application areas until Philips came in 1971 with its own minicomputer range, the P800 Series. An LSI remake of the DDP-416 in a rack mounted outfit and targeted for instrumentation and process control applications was marketed as PC-2200 (the only difference with the original DDP-416, from hardware/software interface point of view, was the non-interruptable JST instruction).

    About the DDPx16 Minicomputer Simulation

    Only a few real and working Honeywell Series 16 Minicomputers still exist today. The links at the bottom of this page point to two websites loaded with the experiences to keep the old hardware running. These sites also present much information about these systems and copies of the old paper tape software in downloadable form.

    People not so lucky to own the real hardware, but still interested to experiment with old computer stuff, have to shift to computer simulation. Fortunately two PC programs exist which are able to simulate a 316/516. The first one is from the Computer History Simulation Project (SIMH), simulating the complete system with all peripherals and options available. The other program simulates a subset, but can be used with a graphical user interface. The experiences reflected by this web site are based on the H-316 simulator from the Computer History Simulation Project, running under Linux. (pls. look at Emulation)

    DDPx16 Software Archive

    As is clear, this site is still in a premature state. There is already much info about this minicomputer range on the Web and links to that info will be added. My own first contribution is a small software archive that will hopefully grow overtime. Focus at this moment is to make the old device driver software available again and more in particular, the listings of those drivers. Although most of the handbooks and the basic (paper tape) software is available on the Web, there are hardly any listings available of that software. And it is from those listings were you get a real feeling of the behavior and understanding of the computer(hardware). They also make it possible to write own programs.

    The device drivers, as part of the standard libraries, were using the most simple form of input/output, the programmed IO channel, using busy-waiting loops to test whether a particular condition for a device is set or a data transfer is ready. These machines exploited sophisticated input/output mechanisms like a Priority Interrupt system Direct Memory Control and Direct Memory Access channels. However all the mechanisms were sold as options and the standard software only supported the standard features.

    The software is recreated from the existing object and self loading tapes as available on the Web. The format presented in the listings is certainly not the format as used by Honeywell in the past. The content of the assembled programs hopefully still is. The modules are not tested in detail; however tests on basic functionality are performed.

    The directories of the Software Archive contain the object files in paper tape format. There are 4 files for each module, where the type of the module file is determined by the file extension:

    - a text file in Unix format (.txt)
    - a source file, which is the converted txt file to DDP ASCII source record format (.src)
    - an object file, which is the assembled source file and which can be linked with the linking loader (.obj)
    - a listing file, which is the output, on a simulated line printer, of the assembly (.lst)

    The driver object files are also collected in a paper tape library for easy linking (see the README in the driver directory).
  • Software Archive
        Last update: Nov 29 '08
  • Emulation
  • Program Examples
  • MTK16
    ddp-116 DDP-116 Console
    courtesy: Adrian Wise
    ddp-116 Basic DDP-116 Machine  
    ddp-516 DDP-516  
    DDP-416 in action

    Note: Windows users who want to display the listings (.lst files) directly via Internet Explorer, have to associate the .lst filetype to Wordpad (File Explorer => Extra/Tools => Folder Options => File Types).
    h-316 H-316 (rack mount)
    courtesy: Philipp Hachmann

    Programming Examples with the Simulator

    Some programming examples with standard software to test and show the possibilities of the simulator are collected on the page Program Examples

    When testing the possibilities of the simulator, also some new software is made for features not supported by the available standard software. Two results of this effort are may be also of some interest for others and published on this web site:

    1) a Small Multitasking Kernel

    2) Moving Head Disk software

    Both pieces of software are not in their end state, but far enough for sharing (pls. look at MTK16)

    own-pc PC simulating a DDP-516 times faster than the original system


    A few documents, not found elsewhere on the internet, describing the DDP516 and 416

    A DDP-516 leaflet (German)

    A DDP-416 leaflet (German)



    Links to related Web Sites

      The Computer Simulation Project (SIMH) SIMH is Bob Supnik's project for simulation of historical computer hardware and software systems. Many old computers are simulated by the simh-program, including the Honeywell DDP-516/H-316. The simulators run under various OSes, including Linux and Windows. The site provides downloadable source and executables of the simulated hardware, software to run on the simulated systems, and links to related sites.

    Honeywell Series 16 The web site of Adrian Wise gives a short intro of the Series 16 machines, its hardware, software and programming. Adrian owns the real hardware but he also provides a simulator which runs under Linux. The simulator can be downloaded from this site, while the site also provides images of original Series 16 paper tape software and links to documentation available on the web.

      H316 Home Philipp Hachtmann is also owner of the real hardware and his site presents many photographs of system parts and the restoration of his machines. On this site is also a downloadable archive available with images of original Series 16 paper tape software and documentation.
      The 3C/Honeywell Legacy Project William Maddox's site is mainly dedicated to DDP-116 machines, planned to be recovered. The DDP-116 was the fist model of the 'Series 16 machines' and with that the predecessor of the DDP516 and H316, with logic built from discrete components. Its descendents, the DDP516 and H361 used integrated circuits instead.
      Bitsavers Software and PDF Document Archive This web site contains a large collection of scanned documents of computers of the past, including documentation about the Honeywell Series 16 machines.



    Page last updated on: March 2 2008 | Contact: