[TUHS] Re: On the uniqueness of DMR's C compiler

[Douglas McIlroy <douglas.mcilroy@dartmouth.edu>]

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There was nothing unique about the size or the object code of Dennis's C
compiler. In the 1960s, Digitek had a thriving business of making Fortran
compilers for all manner of machines. To optimize space usage, the
compilers' internal memory model comprised  variable-size movable tables,
called "rolls". To exploit this non-native architecture, the compilers
themselves were interpreted, although they generated native code. Bob
McClure tells me he used one on an SDS910 that had 8K 16-bit words.

Dennis was one-up on Digitek in having a self-maintaining compiler. Thus,
when he implemented an optimization, the source would grow, but the
compiler binary might even shrink thanks to self-application.

Doug

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