APM / Fred machine and monitors

Some more good photos on the EMAS site
It was mentionend in this thread but I think it’s worth to make a separate one.

The APM is interesting, but it’s (hardware) design is not that spectacular to me, There are other rack computers. I more like the 2 monitors here. Can anybody identify them?
There is much software available, some in binary .MOB format, some in source, mainly IMP.
Here are some games including Pacman.
An emulator would be great.

My recollection would be that an ordinary text terminal would be the usual interface, and then if the Fred machine had a frame buffer, the pixel-addressable graphics would be displayed on a colour monitor. (It might be that all Freds had a frame buffer, but I doubt it, as you wouldn’t need one for many purposes.)

Most graphics details are explained in the PDF, I posted.
There were different Freds with different graphics cards.
Mainly “Level 1” with Intel 82786 which is EGA like but had 8 colors.
Then there was an optional board Level 1.5 with 256 colors out of 32,768.
Frame buffers with packed pixels.

Terminal monitors were Visual 200, Visual 55, VT100, VT220.
The graphics monitor is a Mitsubishi C3419E. I haven’t found any info on that one. And no pics on the web except the ones on the EMAS site.

It could only display 688x512 pixels (of the 1024x1024). Details on the source file apm_wd.txt
The previous emulation had no video emulation. I wonder how they made the screenshots of the games.

Here are a couple of snippets from APM Working Documents (here as doc, here as pdf and here as text, which is the apm_wd.txt mentioned above):

    This document describes the Department of Computer Science’s Advanced Personal Machine, (APM). It is part of a general computing environment that has been evolved over a number of years. There already is an extensive communications network in the department which has a filestore, print server, VAX 11/780, Perkin Elmer 3220 and a number of Interdatas attached to it. The services and facilites offered by these systems are described elsewhere and the APM makes extensive use of them.
  The Department's Advanced Personal Machine is one version of a modular computer system designed to allow easy experimentation with both software and hardware. A major aim of this development has been to provide maximum flexibility of configuration, so that it would be possible within the overall framework to experiment with a variety of architectures and processors. Accordingly the system is constructed around general-purpose a moderate-performance bus, shareable by several processors and permitting easy expansion of memory capability. The bus supports full 32-bit data operands and 32-bit (byte) addresses, with separate data and address lines. 

  The basic version of the system has a single processor board utilising the Motorola 68000 microprocessor and one or more 1/2 megabyte memory boards. The processor board interfaces to a standard video terminal and to the Department's Ethernet-type network. There is no permanent local storage in the basic machine, all files being held on remote file servers accessed over the network. 

  A system configured with more than one active processor(bus master) also requires to have a arbitration board. It is desirable, but not essential, to have this board on the single processor configuration. 
  Optionally, a system may incorporate either of two levels of graphics capability. The lower level provides a passive frame-store memory which allows direct access from the ordinary processor to individual pixels; the second level puts the frame-store under the control of a programmable graphics processor. 

In due course the processing capability of the system will be enhanced by the provision of user-level processor boards, incorporating a virtual memory capability, based on the latest fashionable parts coming onto the market, such as the Motorola 68010, the National Semiconductor 16032, and the Intel 80286. The present control processor boards will be retailed as input/output controllers and system monitors in this multi-process or configuration.

The existing operating system supports a single-process environaent and is an interim a development vehicle for hardware testing and evolution of the full system software. In due course the operating system will consist of a smsall nucleus concerned with process creation and synchronisation, together with an open-ended set of modules, selectable at will according to configuration and user needs.


The frame store is an array of 1024*1024 pixels. Pixel (0,0) is at the bottom left of the array and pixel (1023,1023) is at the top right of the array. The attached monitor will display a rectangular sub-region of this array. The size of the displayed area is determined by the Monitor specifications and is configured by PROM’s on the graphics board. The display area for the Mitsubishi C3419E monitors is 512(V)*688(H) pixels.

I notice that in addition to the 32000 and 80286 cross assembler, there was in due course an ARM cross assembler, although ARM isn’t mentioned in that 1983 document, of course.

Great, it plays Spacewar in full resolution! :slight_smile:
(PS: I’m shocked that it’s not in that list of games.)

Maybe it’s possible to use the 68000 binary .MOB files on existing emulators or disassemblers.
And concerning cross assemblers.
I’m also interested in the EMAS and EMAS 2+3. Unlike the APM, they are for real mainframes (System 4-75, ICL 2900). And there’s a boot disk/memory dump.

There are IBM converters (EMAS 3, docs IBMOBJUTILS and OS/emas/users/ercc07) but I think someone has to do run them within that system. I also read about cross assemblers or compilers for a VAX. At least there are sources.

On the EMAS site some infos are in folders, I wouldn’t expect. I found interesting 2900 stuff (including disks in different formats) in folder DEIMOS (I think in OS).
Some infos in user contents or spread in other folders.

System files of EMAS 2 should be on a disk/folder called ERCC10, but I haven’t found that one.
Interesting is also the ASM code of EMAS 370 self loading dump (slds.imp).
All source codes are interesting, but it’s almost too much to read.
APM is also widespread. At least there’s a full tar file.