marketing unix

[Guy Harris]

> TO Erik E Fair,
> I have not personally used BSD unix so I can't make any speed claims,

The file system is definitely faster.

> BUT how upward compatable is 4.1 to 4.2??

4.2BSD has a "compatibility mode" option where any VAX-11 binary built for
4.1BSD will execute under 4.2BSD, unless it tries to read directories (the
directory format changed).

> All AT&T BTL Unix's are upward compatable.

If one takes that statement literally, so that "AT&T BTL UNIXes" isn't the
same as "BTL UNIXes" (i.e., only referring to UNIXes offered *after* BTL
changed it's name to AT&T BL), it's not a big statement; the only UNIX AT&T
BTL ever offered was System V (can an S5R2 linker handle S5R1 object
modules)?  If one takes "AT&T BTL" to refer to Bell Labs generically, it's
false as V6 wasn't upward compatible with V7, and (more importantly) V7 wasn't
upward compatible with System III.

	Guy Harris
	{seismo,ihnp4,allegra}!rlgvax!guy