Unix 3.0 vs V7

[utzoo!henry]

There is a nontrivial amount of evidence that Unix 3.0 (I've never seen
anything from Bell that calls it "III", although I may not be up to date)
is not in fact a direct derivative of V7, but split off from the "Mother
Unix"'s line of development somewhat earlier.  I have no access to 3.0
sources, but I have seen and studied a copy of the manual (warning:  there
is no guarantee that the manual I saw exactly matches the system that will
be released).  There are a number of decidedly peculiar things, like:

	- There are no multiplexed files.  At all.
	- Ditto no packet driver.
	- There are occasional archaic things that are gone from V7.
	- The function of V7 dup2() is accomplished in a completely
		different and much more cumbersome way.
	- There is internal evidence that ioctl arrived late (there is
		a separate system call to set things like the close-on-
		exec bits on file descriptors).

A plausible hypothesis is that 3.0 is the descendant of a system that
split off from the "main line" of development shortly after the
32-bit filesystem cutover but before a number of other changes that
preceded the V7 release.

What to do about it?  Well, one can go with Berkeley.  I don't plan to
do that partly because I'm running 11s and not Vaxen, and partly because
I'm not very happy about some of the things Berkeley has done to Unix.
My own plan is to stick with V7 as the base system and to add in various
useful things from 3.0 as the need and/or inclination arises, while avoiding
some of the more awful things.  (I haven't made up my mind about the horrid-
but-versatile tty interface yet.)