cron and DST

[Guy Harris]

>Our 3B2's running sysVr3.1 ran all the crontab entries twice after
>the change from DST.  I kind of expected that for the entries between
>1 and 2 AM, but the subsequent entries also ran twice.  Is this
>normal?

No.

It's caused by "cron" not understanding how to deal with converting
local time <-> UNIX time and, in particular, how to deal with DST.  I
don't remember the details; it's fixed in SunOS 4.0 (which has a "cron"
based on the S5R3.1 one) by having "cron" use "timelocal" to do the
conversions rather than trying to do them itself.

Unfortunately, S5R3.1 doesn't have "timelocal" (converts a "struct tm"
into a "time_t"); it's from the Arthur Olson time zone code, which SunOS
4.0 uses.  S5R4 will have "mktime", assuming it supports ANSI C, which
pretty much does the same thing.