[comp.mail.mh] FAQ

jqj@duff.uoregon.edu (JQ Johnson) (04/06/91)

In the recently posted FAQ appears the advice that people should use the
(otherwise undocumented?) LOCKF option when building mh 6.7.  After I read
the FAQ, I looked at the code, found that the option did in fact exist
(basically, it means that Unix-style locking uses mandatory lockf()
instead of flock()), and rebuilt my mh 6.7.1 distribution for my set of
SPARCstations running SunOS 4.1.1.  We run with an NFS-shared
/var/spool/mail, so lockf() semantics (being global to the NFS system) are
in principal better than flock.

First thing I noticed was that zotnet/mts/lock.c didn't compile.  In
SunOS 4.1.1 you need to include <sys/unistd.h> to get the symbol
F_ULOCK.  OK, easy to add...

Almost immediately after rebuilding I started seeing problems; whenever a
workstation crashed it would result in a hung lock, forcing me to kill and
restart rpc.lockd and rpc.statd on the server for /var/spool/mail.  Worse,
I presume that /bin/mail (which sendmail calls to do delivery) uses
*.lock style locking, so the major potential contention problem on one's
maildrop is not addressed with LOCKF-style locking.  I've rolled back.

Have other people using Suns been using the LOCKF option?  With what
success?  I note that the option uses *mandatory* locks, a feature that
Sun strongly deprecates.

Bottom line is that I believe that the FAQ is wrong, and that at least on
SunOS one should *not* define LOCKF and should use LOK_BELL instead.
So, I recommend in mtstailor:
	lockstyle: 1

-- 
JQ Johnson
Director of Network Services		Internet: jqj@oregon.uoregon.edu
University of Oregon			voice:	(503) 346-1746
250E Computing Center			BITNET: jqj@oregon
Eugene, OR  97403-1212			fax: (503) 346-4397

wohler@sapwdf.UUCP (Bill Wohler) (04/25/91)

[this was posted a while ago, but i don't think it hit the airwaves.  --bw]

folks,

  the section in the FAQ about compiling options generated some
  controversy this month.  first, regarding ATZ:

From:    Tony Landells <ahl@technix.oz.au>
Yes; very pretty.  How unfortunate that timezone names are so
ambiguous, so that EST can be interpreted, at a minimum, as (American)
Eastern Standard Time, (Australian) Eastern Standard Time, or
(Australian) Eastern Summer Time (and yes, I think it's dumb having
the same acronym for both normal and Summer time, but that's a
different problem).  While the numeric timezones may not look as nice,
they are, at least, reasonably unambiguous.  I would urge anyone who
ever intends/hopes/expects to use e-mail outside the U.S. to NOT use
ATZ (sorry Stephen).

  my feelings were that they are coming out with better, less
  ambigous timezone names such as PDT8PST and MET-1DST (the two that
  are close to my heart), although the ATZ implementations i've seen
  seem to use the older, shorter, ambiguous terms.

  thus, my question is this: should we modify the FAQ text on ATZ as per
  above, or modify the sources to use better timezone names?

  secondly, you've all just read about mr. johnson's experience with
  LOCKF.  was this a singular experience, or is this true on
  everybody's sun?  should the FAQ be amended to include the
  following:

Bottom line is that I believe that the FAQ is wrong, and that at least on
SunOS one should *not* define LOCKF and should use LOK_BELL instead.
So, I recommend in mtstailor:
	lockstyle: 1

  yer 'umble servant,
-- 
						--bw
-----
Bill Wohler <wohler@sap-ag.de> <sapwdf!wohler>
Heidelberg Red Barons Ultimate Frisbee Team

gildea@EXPO.LCS.MIT.EDU (Stephen Gildea) (04/26/91)

Sounds to me like we should just leave all mention of options out of
the FAQ.  The MH authors knew what they were doing when they made them
options, because what is an obvious setting for one site seems not to
be at all appropriate for another.

Or perhaps the FAQ should expand on the mh-gen information on options
and discuss the pros and cons and general experience people have had
with various settings, without making recommendations.

The international perspective on ATZ should be added to the mh-gen
manual page.

 < Stephen

kre@cs.mu.oz.au (Robert Elz) (04/27/91)

wohler@sapwdf.UUCP (Bill Wohler) writes:

>  my feelings were that they are coming out with better, less
>  ambigous timezone names such as PDT8PST and MET-1DST

These things aren't timezone names, they're timezone specifications,
ie: they're uses on Sys V type systems in the TZ environment variable
to tell the ctime() type library functions what timezone your system
is in.

>  or modify the sources to use better timezone names?

You can't do that - rfc822 is very explicit on which timezones
are legal in mail headers.

There's actually nothing at all ambiguous about a legal rfc822
date header, with or without an ascii timezone name.

The problem is that rfc822 is very (VERY) US-centric in this,
the rest of the world was just forgotten.   If you're not in the
US, you MUST use numeric zone specifications (except if you're GMT).

As a general principle, it would probably be better if everyone
just switched to use the numeric zone names for transmission (its
just fine for mail readers to display the zone as a name, using
whatever local conventions make sense).

kre