14 Sep
2017
14 Sep
'17
10:49 a.m.
Doug, could you talk about this some more? Sort of like Reddit's
explain it like I'm 5? Assume I'm dense but want to learn and tell
me how this worked again. Threaded? I'm guessing you mean that it
did paging, did that need threads in the current sense?
On Wed, Sep 13, 2017 at 11:48:44PM -0400, Doug McIlroy wrote:
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Larry McVoy lm at mcvoy.com http://www.mcvoy.com/lm
Check out:
ybc: a compiler for B <https://github.com/Leushenko/ybc>
From a historical standpoint, a plain B compiler
lacks a very important
attribute of B in Unix. Yes, B presaged some C syntax. But
its shining
property was that it produced threaded code, for which both compact
and expanded runtime support was available. The latter had software
paging. Thus B transcended the limited physical memory of the early
PDP-11s.
If you can't compile something, you can't run it. A prime example was B
itself. Without software paging it would not have been able to recompile
itself, and Unix would not have been self-supporting.
Doug