Oldest known version of DOS unearthed – MS-DOS ancestor 86-DOS version 0.1 C is now available on the Internet Archive

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Disk contains just nine files, two of them for a chess game.

86-DOS version 0.11
(Image credit: Archive.org / f15sim)

An incredibly early release of 86-DOS has been found, imaged, and shared on the Internet Archive. The disk appears to be an original release of version 0.1 C of 86-DOS from Seattle Computer Products (1980) and includes several utilities, along with a game. Moreover, according to the disk label, what we see is just the eleventh disk off the duplication line. This is an important finding, as 86-DOS is a direct ancestor of PC DOS and MS-DOS.

(Image credit: Archive.org / f15sim)
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9 Comments Comment from the forums
  • coromonadalix
    where's my Dolorean loll wow loll they still exist ... and the guy put other oldies on Archive. ...
    Reply
  • adamXpeter
    abufrejoval said:
    When you wrote "Here is one of the earliest builds of what became Microsoft's darling.It's been compiled in July 1980, and less than 10 people had seen it.Until now." that immediately rang wrong, because compilation at the time was stricly applied to high level languages and I'm rather sure this was written in assembly code.

    In fact I'd hazard that pretty nearly all DOS variants like its CP/M brethren were written in assembly, which is why Unix was such a revolutionary approach when it was re-written in C.

    But even if the 8088 in fact allowed for the giant amount of 640KB of RAM, the first generation systems often had much less, wouldn't even have the full complement of 64KB. Pretty sure the original IBM-PC actually didn't take more than 64KB on the mainboard but at the time RAM expansion was still done via expansion cards.

    When you fight for every byte you didn't dare use a compiler for a DOS, even if you had one, which early on they obviously didn't.
    Please note that assembly is not machine code, it is compiled, too.
    Reply
  • leoscott
    abufrejoval said:
    When you wrote "Here is one of the earliest builds of what became Microsoft's darling.It's been compiled in July 1980, and less than 10 people had seen it.Until now." that immediately rang wrong, because compilation at the time was stricly applied to high level languages and I'm rather sure this was written in assembly code.

    In fact I'd hazard that pretty nearly all DOS variants like its CP/M brethren were written in assembly, which is why Unix was such a revolutionary approach when it was re-written in C.

    But even if the 8088 in fact allowed for the giant amount of 640KB of RAM, the first generation systems often had much less, wouldn't even have the full complement of 64KB. Pretty sure the original IBM-PC actually didn't take more than 64KB on the mainboard but at the time RAM expansion was still done via expansion cards.

    When you fight for every byte you didn't dare use a compiler for a DOS, even if you had one, which early on they obviously didn't.
    Memory16 KB – 256 KB (motherboard)
    Reply
  • Joseph_138
    I would fully expect Microsoft to send in the lawyers. Technically, DOS is still under copyright protection, as it isn't old enough, yet. The first Mickey Mouse cartoon has only just passed out of copyright protection, and that was released in 1928.
    Reply
  • Korgz
    adamXpeter said:
    Please note that assembly is not machine code, it is compiled, too.
    Except it isn't. Assembly language is "Assembled" by either a single pass or multi-pass assembler. Note: if it was actually compiled then it would indicate a level of portability that Assembly simply does not have. Before commenting I would recommend you do a few tutorials or actually try writing your own assembly code as it would teach you the basics of how opcodes, operands from an assembly language etc get assembled into machine code.
    Reply
  • dmitche31958
    Admin said:
    An incredibly early release of 86-DOS has been found, imaged, and shared on the Internet Archive. This is an important find as it is a direct ancestor to PC DOS and MS-DOS.

    Oldest known version of DOS unearthed – MS-DOS ancestor 86-DOS version 0.11 is now available on the Internet Archive : Read more
    I'm sorry but this is so not interesting that I have to respond. This is not similar to finding a "direct ancestor", but simply an earlier, undeveloped work-in-progress. No one will be jumping through hoops to download and use it. There is no new found information here, other than to show what hadn't been developed into the OS at this point in time.
    Reply
  • JeffreyP55
    Admin said:
    An incredibly early release of 86-DOS has been found, imaged, and shared on the Internet Archive. This is an important find as it is a direct ancestor to PC DOS and MS-DOS.

    Oldest known version of DOS unearthed – MS-DOS ancestor 86-DOS version 0.11 is now available on the Internet Archive : Read more
    Not very excited. Taught myself DOS way back in the Pleistocene. No need to revisit it. A minimalist few commands still in windows.
    Reply
  • adamXpeter
    Korgz said:
    Except it isn't. Assembly language is "Assembled" by either a single pass or multi-pass assembler. Note: if it was actually compiled then it would indicate a level of portability that Assembly simply does not have. Before commenting I would recommend you do a few tutorials or actually try writing your own assembly code as it would teach you the basics of how opcodes, operands from an assembly language etc get assembled into machine code.
    In computing, a compiler is a computer program that translates computer code written in one programming language (the source language) into another language (the target language).

    A translator or programming language processor is a computer program that converts the programming instructions written in human convenient form into machine language codes that the computers understand and process. It is a generic term that can refer to a compiler, assembler, or interpreter—anything that converts code from one computer language into another. These include translations between high-level and human-readable computer languages such as C++ and Java, intermediate-level languages such as Java bytecode, low-level languages such as the assembly language and machine code, and between similar levels of language on different computing platforms, as well as from any of these to any other of these.

    You should enjoy more machine code without an assembler and a linker. See the example here: https://www.ibm.com/docs/en/zos/2.1.0?topic=guide-sample-program

    It is enough if you assemble "145+reallylongsymbol st 7,a8+8*(b5-constant-7)(3)" to machine code.
    Reply
  • USAFRet
    adamXpeter said:
    In computing.....
    @adamXpeter

    Don't just copy/paste from Wikipedia.

    Give us some context of what you're saying.
    And when you DO copy/paste text, give attribution to where it came from.
    Reply