From: utzoo!decvax!decwrl!sun!megatest!fortune!hpda!hplabs!hao!seismo!rlgvax!guy
Newsgroups: net.micro,net.wanted
Title: Re: Which small UNIX system would YOU buy?
Article-I.D.: rlgvax.175
Posted: Thu Mar 31 12:35:47 1983
Received: Sun Apr  3 04:08:41 1983
References: mcnc.1616

A couple of comments for the respondees:

1) Re: Zilog - another annoyance is their habit of changing things for the
sake of change.  Our (pre-release, admittedly) Zeus 2.2 DOES NOT HAVE A
"UMASK" COMMAND IN THE BOURNE SHELL!  Instead of "umask nnn", you say
"set umask = nnn"; much more user-friendly, no?  Why didn't they do something
like changing "umask" so that you can give "chmod"-like values to it instead
of making useless changes to the syntax - which make existing shell files NOT
WORK?  (They probably would have done it to the C shell, too, except that
"set umask = nnn" already sets the variable "umask" to "nnn".)  They also
borrowed Berkeley's idea of /etc/ttytype - a good idea (who wants to have to
tell UNIX what kind of terminal they're on every time they log in?) - but
they they screw it up by limiting the terminal type to two characters!
Furthermore, their clever calling sequence CAN'T BE DISABLED WITH A COMPILER
OPTION, which makes "adb" next to useless.  Plus, when they added "curses",
they did an excellent port, except they forgot that the "*printw" routines
take a variable number of arguments and have to be changed to work on Zeus...

2) Re: System V on an 11/23 - real live System V kernel, IPC, shared memory,
semaphores and all?  Bell sort of half-heartedly supported System III on
non-separate-I&D machines (it was basically the V7 support with: disk buffers
out of kernel address space, and the U page copied on context switches instead
of map - sure, it saves address space, but I hope it doesn't do very many
context switches), but System V was a good deal bigger and they claimed only
to support 11/45s and 11/70s (not even 11/44s - USG UNIX uses the second
register set, which 11/44s don't have, but you could easily change it not to,
at the cost of making some of the copy routines a bit slower; does anybody know
whether the second register set makes a significant difference?).  The "correct"
solution is probably to use an overlay scheme (for a lot of PDP-11 work, I
think the lack of any overlaying is the biggest problem with UNIX) for the
kernel and user code; the HCR overlaying scheme for V7 will probably work for
USG UNIX as well - it uses a separate stack for the overlay stack, so it
requires no change to the C stack frame. Did you get such a kernel or roll
your own?  (For that matter, I thought RSX-11M+ required split I&D space, too,
but I've heard claims that P/OS is based on M+, not on M, and that M+ runs
on 11/23s.  Does it no longer require split I&D space, or has DEC come out with
a split I&D space mode for the 11/23 or 11/23+?)

						Guy Harris
						RLG Corporation
						{seismo,mcnc,we13}!rlgvax!guy