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Re: RFC 99 (v3) Standardize ALL Perl platforms on UNIX epoch

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From:
Russ Allbery
Date:
September 20, 2000 13:03
Subject:
Re: RFC 99 (v3) Standardize ALL Perl platforms on UNIX epoch
Message ID:
ylpulyu8z9.fsf@windlord.stanford.edu
Bart Lateur <bart.lateur@skynet.be> writes:

> This is bad. That system is broken. ;-) I guess that it's the same
> situation on MS-DOS, since there the hardware clock is usually set to
> local time. It could even happen on Win32?!?

> This surely was a bad design decision from the hardware guys. Very
> shortsighted.

It's not a hardware problem; the hardware clock just keeps a time.  It has
no concept of time zones.  It's a software problem; back when DOS was a
dead-simple operating system, Microsoft decided to interpret the time as
local time, probably because that was simpler and getting time zones right
is hard (and a larger problem than DOS was really prepared to handle,
since programs mostly bypassed it and programs mostly want local time).

Of course, it then gets into the backward compatibility feature matrix and
never goes away.

Note that Linux gets this right, making it obvious that it's not a
hardware problem.  (Actually, Linux gives you the option of interpreting
the hardware clock as UTC or as local time, so that you can do the latter
for compatibility with Windows, but if you do that it adjusts the hardware
clock with your time zone information before setting the system clock in
the kernel at boot.)

-- 
Russ Allbery (rra@stanford.edu)             <http://www.eyrie.org/~eagle/>

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