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    SubjectRe: Linux-asm (was A patch for linux 2.1.127)
    On Thu, 19 Nov 1998, Simon Kenyon wrote:
    [quote snipped]
    > unix never ran on an 8
    > it was originally developed (in assembler) on a 7
    > when the moved from the 7 to the 11/45 they rewrote it in c

    ]SET MODE RAMBLE[
    The reason you see the word "segment" here and there in Unix is probably
    because the 11/45 had a two-segment memory mapping model. Having
    separate "I-space and D-space" (instructions, data) doubled the
    theoretical memory capacity of the machine, and by that time more memory
    was a welcome improvement. This model also appeared on the earlier PDP10
    systems (called HISEG/LOSEG there -- the HISEG was code and the LOSEG data).
    Other PDP11 models had addin boards for segmented memory, but I think the
    11/70 was the first that had (or could get) what we'd recognize as virtual
    memory.

    > now - what i don't know is how the c compiler was bootstrapped
    > i have vague recollections that the first c compiler was written in bcpl (which was
    > an interpreter written in assembler)

    C has a long chain of ancestors. C <- B <- BCPL (basic CPL) <- CPL
    (Combined Programming Language, I think) which doubtless came from
    something else, but my knowledge stops there.

    This thread should probably move to comp.os.old-fogeys or whatever.

    --
    Mark H. Wood, Lead System Programmer mwood@IUPUI.Edu
    Innovation is only valuable if it improves one's life; otherwise it's
    just one more silly change to cope with.


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