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From: amanda@visix.com (Amanda Walker)
Newsgroups: comp.sys.mac.system
Subject: Re: Timekeeping
Message-ID: <1991Feb26.015340.7590@visix.com>
Date: 26 Feb 91 01:53:40 GMT
References: <1991Feb25.203351.886@Neon.Stanford.EDU>
Organization: Visix Software Inc., Reston, VA
Lines: 30

cheshire@Neon.Stanford.EDU (Stuart David Cheshire) writes:
>1. How does System 7 work? Does it use GMT internally like UNIX?

Not that I know of.

>2. What ideas do people have on this problem?

Well, the Script Manager stores the current offset from GMT (as well
as a currently unused Daylight Saving Time offset), so it is possible
to convert to GMT without much problem.  AppleShare also addresses
this problem in a fairly cool way: when you sign on to a file server,
the Mac computes the time differential between itself and the server,
and (I believe) factors this into any time calculations.  This helps
to prevent the kind of "time skew" you sometimes see on NFS servers
that aren't running NTP (network time protocol).

The basic problem is that the Mac file system stores local times, on
the assumption that the Mac is not going to change time zones, which
is not as good an assumption as it used to be.

It might be possible to write an INIT that would adjust file times by
the current GMT offset.  This would take care of a lot of the problem,
as long as you used the Map control panel to indicate that you've moved
the Mac, instead of changing the time directly...

-- 
Amanda Walker						      amanda@visix.com
Visix Software Inc.					...!uunet!visix!amanda
--
There can't be a crisis next week--my schedule is already full.