]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.
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/