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Thread: Anyone know anything about the IBM System/23 DataMaster?

  1. Default Anyone know anything about the IBM System/23 DataMaster?

    Anyone know any details about this systems internal operation?

    I've looked through a few manuals, but they're high level operator manuals.

    The machine (as I understand it) is an 8085 with 256K of bank selected RAM.

    It was also apparently able to support 2 users.

    It has BASIC as its major operating environment, supplemented by special utility programs that do things that BASIC can not.

    Naturally there's no low level programming manual, it doesn't seem to have been designed to develop low level programs on it.

    Does anyone know how the RAM was utilized? How much RAM was available to BASIC programs for example. How the multi user aspect worked. I noticed there's commands for file locking and such, so it's conscious of its multi user status and the problem they can bring.

    It's a clever machine that came out just a bit too late, but I'm curious about the internals and operating environment, the underlying executive, memory usage, etc. that anyone might be able to share.

    It's a clever machine, to be sure.

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    The RAM usage is explained on pages 2-54 and 2-55 of the IBM 5324 Computer Service Manual.

    The address space is divided into 4 16k blocks; two of those blocks are devoted to ROS and the other two to RAM. The first ROS and the first RAM block do not page. 256k of ROM could be paged in the page-able 16k ROM block. Similarly, 112 k of RAM could be paged through the 16k of address space allotted to RAM paging.

    If you have used something like the BBC Micro with its sideways ROMs, the memory layout concepts would look familiar.

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    Isn't the Datamaster an EBCDIC machine, also?

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    Quote Originally Posted by krebizfan View Post
    The RAM usage is explained on pages 2-54 and 2-55 of the IBM 5324 Computer Service Manual.
    This was helpful, thank you. It seems there was 16K of "common" RAM, and 16K of pageable RAM, with 7 16K RAM pages (total 112K).

    This is all hidden from the user, I'm curious how BASIC (among other things) leveraged this RAM.

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    Someone has extracted all the Read Only Storage contents so it might be possible to figure out what the BASIC code does.

    As far as documented memory usage, there isn't much information. The Datamaster Procedures and Techniques booklet explains how memory is assigned to disk buffers and indexes. Get this booklet if you have any plans to use a Datamaster. Some significant bugs are also addressed.

    The report programming guide indicates that only the largest reports would require a system with more than 64k of RAM.

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    I thought it had FORTH built in?

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