From: OLIVOTTO%ITNCISCA.bitnet@icineca.cineca.it (OUT, OUT - YOU'LL NOT FEEL THE FALL-OUT...)
Newsgroups: comp.unix.wizards
Subject: (From: IN%"UNIX-WIZARDS@BRL.MIL") UNIX-WIZARDS Digest  V16#035
Date: 11 Oct 92 22:23:16 GMT

UNIX-WIZARDS Digest          Sun, 11 Oct 1992              V16#035

Today's Topics:
                            SVR4 VM question
                      Re: fork() and forget..How?
                           Re: Disk leakage?
Intro to comp.unix.wizards - read before posting! (weekly announcement, last
 change: Jul 31 10:30)

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From: Jerome Christatos /ADVISOR Clay <rcs08945@zach.fit.edu>
Subject: SVR4 VM question
Date: 7 Oct 92 01:49:37 GMT
Followup-To: comp.sys.sun.misc
To:       unix-wizards@sem.brl.mil


        Hello,

        I have one questions for the Unix SVR4 or SunOs gurus.

        It seems that in the function ufs_getapage()/ufs_vnodeops.c
        f the filesystem has a block size of 4k and the page (8k) is
        found in the cache , the second part of the page ( the 2nd
        block ) is always read in memory . ( although this section
        of code is also used for read-ahead when the block size is
        8k ).

        Can someone confirm this ?

        Thank you.

                                        J. CHRISTATOS
                                ( rcs08945@zach.fit.edu )

-----------------------------

From: Kartik Subbarao <subbarao@tex.princeton.edu>
Subject: Re: fork() and forget..How?
Date: 9 Oct 92 14:52:48 GMT
To:       unix-wizards@sem.brl.mil

In article <1992Oct8.230259.1749@infodyn.com> jth@infodyn.com (Jabba The Hutt)
 spews::

>Kirk,
>
>You should learn about a couple of wonderful keys on your keyboard...
>the space bar and the Return key.  This article is more than a little
>confusing when every time i resize the window, the picture changes!!!

Jabba The Hutt,

        You should learn about a wonderful thing known as waste of bandwidth. If
you don't have the intelligence to comprehend what Kirk was saying, then
don't reply. Go back to slave trade.

        -Kartik

-----------------------------

From: Kartik Subbarao <subbarao@tex.princeton.edu>
Subject: Re: fork() and forget..How?
Date: 9 Oct 92 14:56:27 GMT
To:       unix-wizards@sem.brl.mil

In article <1992Oct9.130646.7250@progress.com> gus@progress.COM (Gus Bjorklund)
 writes:
>
>You also should make sure that when the parent exits, it wait()'s
>for any children which have not yet finished.

This is not necessary. If a child process dies, and it's parent isn't
around, then it will become adopted by init, who will dutifully wait() for
it.

        -Kartik

-----------------------------

From: "D. J. Bernstein" <brnstnd@nyu.edu>
Subject: Re: fork() and forget..How?
Date: 11 Oct 92 05:22:31 GMT
To:       unix-wizards@sem.brl.mil

What a shame that fork() doesn't return a file descriptor...

---Dan

-----------------------------

From: Albert Cheng <acheng@ncsa.uiuc.edu>
Subject: Re: Disk leakage?
Date: 9 Oct 92 16:21:15 GMT
Originator: acheng@shalom.ncsa.uiuc.edu
To:       unix-wizards@sem.brl.mil


In article <BvtCFB.I1F@news.cso.uiuc.edu>, acheng@ncsa.uiuc.edu (Albert Cheng)
 writes:
>Try "pstat -i" which shows all inodes in use, together with the sizes,
>UID, etc.  Then use "ps axl" to get a list of processes of the same UID
>for further investigation.  But I don't know of a simple tool to find
>the PID(s) that reference the inode.  Any suggestions from real
>wizards?

[Yes, I am responding to my own post.  It is lonely here. :-)]

Someone told me a tip of a PD tool called "ofiles" that shows
the information of processes "linked" to an open file.  Try
"archie ofiles" or "archie ofiles.c" to locate it.

-----------------------------

From: Paul Smee <smee@bristol.ac.uk>
Subject: Re: Disk leakage?
Date: 9 Oct 92 16:32:35 GMT
To:       unix-wizards@sem.brl.mil

In article <BvtCFB.I1F@news.cso.uiuc.edu> acheng@ncsa.uiuc.edu (Albert Cheng)
 writes:
>
>In article <1992Oct8.095328.4108@bristol.ac.uk>, smee@bristol.ac.uk (Paul Smee)
 writes:
>>We've got a mystery, in that large (in our context) chunks of disk
>>occasionally mysteriously vanish, to reappear if you reboot.  I believe
>>I understand the mechanism, question is a bit deeper than that.
>
>Try "pstat -i" which shows all inodes in use, together with the sizes,
>UID, etc.  Then use "ps axl" to get a list of processes of the same UID
>for further investigation.  But I don't know of a simple tool to find
>the PID(s) that reference the inode.  Any suggestions from real
>wizards?

Thanks, I'll check that as a possibility.  Couple of people have
suggested progs called 'lsof' (list open files, presumably?) and
'ofiles', both of which are reputedly public domain.  I was going to
have a scan around archie for them.

--
Paul Smee, Computing Service, University of Bristol, Bristol BS8 1UD, UK
 P.Smee@bristol.ac.uk - ..!uunet!uknet!bsmail!p.smee - Tel +44 272 303132

-----------------------------

From: Paul Smee <smee@bristol.ac.uk>
Subject: Re: Disk leakage?
Date: 9 Oct 92 16:41:41 GMT
To:       unix-wizards@sem.brl.mil

In article <1b1r86INNock@early-bird.think.com> barmar@think.com (Barry Margolin)
 writes:
>I don't think a zombie process can have open files.  The only state that a
>zombie process has is it process table entry, which holds the information
>that the parent may extract using getrusage(2).

No one here, including better folk than I, really has much clue what
zombies can and can't do.  Useful info, thanks.

>I've never heard of any of the standard daemons or system processes doing
>stuff like this, either.

We're running some pretty weird (and occasionally UK specific, eg NIFTP)
stuff...

>You could try killing and restarting processes one by one, to see when the
>disk space becomes available.

I'm sort of holding that idea in reserve, as most of the things this
beast is running are pretty mission-critical over our entire service.
(It's our mail hub, our primary IP domain nameserver, one of our
'uk.ac.bristol' NRS local registries (more or less the UK colored-book
protocols' analog to DNS), and so on.  Also, most importantly, our news
machine. :-)  All but news have 'backup' points, so we could live
without bits of it for a bit, but the cut-over from primary to backup
for some of these services does nasty user-visible things.  Still, I
may get desperate enough.  Thanks for the thoughts...

--
Paul Smee, Computing Service, University of Bristol, Bristol BS8 1UD, UK
 P.Smee@bristol.ac.uk - ..!uunet!uknet!bsmail!p.smee - Tel +44 272 303132

-----------------------------

From: "D. J. Bernstein" <brnstnd@nyu.edu>
Subject: Re: Disk leakage?
Date: 11 Oct 92 05:09:42 GMT
To:       unix-wizards@sem.brl.mil

In article <1b1r86INNock@early-bird.think.com> barmar@think.com (Barry Margolin)
 writes:
> I don't think a zombie process can have open files.

Zombie processes can have open files and quite a bit more state. On a
variety of BSD systems you can see this using pff from my kstuff
package.

---Dan

-----------------------------

From: Jane Valencia <jtk@netcom.com>
Subject: Re: Disk leakage?
Date: 11 Oct 92 15:36:57 GMT
To:       unix-wizards@sem.brl.mil

brnstnd@nyu.edu (D. J. Bernstein) writes:

>> I don't think a zombie process can have open files.
>Zombie processes can have open files and quite a bit more state. On a
>variety of BSD systems you can see this using pff from my kstuff
>package.

I think you need to start listing particular operating systems.  On
the (BSD-based) operating systems I've worked on, the exiting process
closes all its files before becoming a zombie.  I'd be *very curious*
to know when the files actually do get closed on a system in which
zombies can still have open files.  This would be particularly
interesting with respect to slow closes (drains on, say, printers),
as it isn't clear to me what process context is going to hang around
while the output drains.

                                        Andy Valencia

-----------------------------

From: Brian Fitzgerald <fitzgb@mml0.meche.rpi.edu>
Subject: Intro to comp.unix.wizards - read before posting! (weekly announcement,
 last change: Jul 31 10:30)
Date: 11 Oct 92 10:00:41 GMT
Expires: Tue, 10 Nov 1992 10:00:24 GMT
Followup-To: poster
To:       unix-wizards@sem.brl.mil

Please take a moment to read this before posting to comp.unix.wizards
for the first time.

comp.unix.wizards is for in-depth discussion of advanced unix topics.

Elementary questions do not belong in comp.unix.wizards.  Although some
socket questions (for example) are appropriate, "How do I program with
sockets?" is not.

Crossposting to comp.unix.wizards and comp.unix.questions is
inappropriate.  Plenty of wizards read comp.unix.questions and answer
questions there.

A wizard is someone who can rewrite the entire system from scratch.  If
you are not a wizard, you are welcome to follow along the discussions
anyway.  You'll learn quite a bit about how UNIX works.  Caution: post
to wizards only if you are yourself a wizard.

For a list of answers to frequently asked questions (FAQ), please refer
to comp.unix.questions (or comp.lang.c, news.answers, etc...).  "How do
I delete a file whose name starts with a '-' ?" is an example of such a
question.  Please do not ask or answer FAQ's on the net.

Write to Unix-Wizards-Request@BRL.MIL (Subject: subscribe.  Any
message.) if you want a daily digest of this newsgroup mailed to you.

To unsubscribe from the unix-wizards mailing list, send mail to
Unix-Wizards-Request@BRL.MIL Subject: unsubscribe.  It is incorrect to
post such requests to the list, or to mail them to me, though others
may mistakenly do so.

E-mail comments about this posting are welcome.  From time to time I'll
summarize them.

Brian
--
These opinions are mine, and do not necessarily reflect those of any
academic department or computing service at Rensselaer.

-----------------------------


End of UNIX-WIZARDS Digest
**************************