Isn't it amazing what you find in the manuals?

John B. Milton jbm at uncle.UUCP
Tue Feb 21 15:23:27 AEST 1989


Well, I was looking in the manuals (gasp!) and found some interesting things.
I have UNIX version 3.51, and was looking in those manuals. I found an
interesting collection of pages at the end of the "User's Manual Volume I".
Most of them are additions for the news xt/layers commands and new document
processing programs. However, there is a duplicate of the BRK(2) page. I
checked it word for word and the only difference is in the second error
condition about shared memory. The one in Volume II says "... greater than
or equal to the start ...", and the one I just found in the back of Volume I
says "... greater than the start ...". Hmm. I assume since they went to the
trouble of putting a new one in Volume I, that it is the correct one. Any
comments?

Another vote that this is the correct one is the presence of a new section
two call: LOCKING(2). I always wondered if the UNIXpc had this one, but I
never had a pressing need for it, so I never tracked it down. One would think
this would be the first step for a business machine... I also wonder why some
UNIX systems call it LOCKF(). Alex S. Crain, alex at umbc3.UMBC.EDU just posted
a list of the known system call access points, and sure enough, there it is:

#define SYS_LOCKING	67	/* locking()		*/

Some other ones look interesting. I have seen references, but don't see any
man pages for:

#define SYS_STTY	31	/* stty()		*/
#define SYS_GTTY	32	/* gtty()		*/

And why were both of these called utime()?

#define SYS_UTSSYS	57	/* utime()		*/
#define SYS_UTIME	30	/* utime()		*/

Hey Alex, where did your info come from anyway?

I assume these extra man pages at the end of Volume I were added at the last
minute. Unfortunatly, (once again probably because they were added at the last
minute) these man pages were printed in such a way that they can't be inserted
where they should be (CHECKMM(1) is on the back of BRK(2)). Hrumph

There is also a new version of COL(1), DIFFMK(1), EQNCHAR(5), KTUNE(7), MM(1),
MM(5), NROFF(1), MPTX(5) and PTX(1). The rest are for new commands.

I just went through Volume II and added "Volume I" to the SEE ALSO section.
The LOCKING page didn't have something else on the back, so I moved that one
between LINK and LSEEK.

I just whipped up a quicky utility to lock a given file. This has it's uses:
Imagine you're hacking away at 3a.m., and you here the click. Oh, I'm being
polled. You check. Aaaahhhhh. That was a disconnect! Aaaaahhh. There's a huge
pile news that just started unbatching...

lock /usr/lib/news/history -z3600 &

Ahhhhh, much better.

I'll post "lock" to unix-pc.sources...
A regular ho-hum user can cause a lot of trouble with this! Consider:

 1. lock /usr/adm/cronlog (hang cron)
 2. lock /unix, and no more nlist("/unix",)!
 3. lock /etc/passwd, and no logins!
 4. lock /bin/sh! (this one doesn't work)
 5. lock /! (this doesn't work either)
 6. lock /tmp/* (good way to make friends)
 7. lock /usr/spool/lp/seqfile (no more printing queueing)
 8. lock /usr/mail/$LOGNAME (flypaper for anyone who mails you)
 9. lock /usr/spool/uucp/SYSLOG (hang all uucicos, thus killing them)
10. lock /usr/spool/uucp/LCK..tty00? MAKE other WAIT for the line.
11. lock /usr/include/stdio.h (everytime I compile, it hangs...)
12. lock /usr/bin/geton.sh (don't let that getty back on)

I have to wonder how many other UNIX systems could be disrupted this way...

John
-- 
John Bly Milton IV, jbm at uncle.UUCP, n8emr!uncle!jbm at osu-cis.cis.ohio-state.edu
(614) h:294-4823, w:764-2933;  Got any good 74LS503 circuits?



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