[COFF] [TUHS] Memory management in Dennis Ritchie's C Compiler

[Tony Finch]

--> COFF

Paul Winalski <paul.winalski at gmail.com> wrote:

mmap() / $CRETVA

> The VMS image activator (runtime loader in Unix-speak) used these
> primitives to load program images into virtual memory.  More than one
> process can map the same region of a file.  This is how sharing of
> read-only program segments such as .text is implemented.
>
> I think Burroughs OSes had this concept even before VMS.

Did MULTICS work the same way?

The Manchester / Ferranti Atlas had virtual memory in 1962 but I don't
know how much they used it for multiprogramming (and by implication shared
text segments) - it didn't do timesharing until later, but AIUI virtual
memory helped it to have an exceptionally good job throughput for the
time. Perhaps their motivation was more to do with having a good shared
implementation of overlays and paged IO.

https://en.wikipedia.org/wiki/Single-level_store

Tony.
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