[Info-vax] VMS Software Bootcamp 2024

[Simon Clubley]

On 2024-09-24, Arne Vajhøj <arne at vajhoej.dk> wrote:
> On 9/19/2024 8:22 AM, Simon Clubley wrote:
>> On 2024-09-18, Tom Wade <nospam at void.blackhole.mx> wrote:
>>> On 2024-09-18 00:25, Lawrence D'Oliveiro wrote:
>>>
>>>> But it?s not ISO 8601.
>>>
>>> Very true, but better than the AM/PM stuff, and unambiguous (unlike
>>> mm/dd/yy or dd/mm/yy).
>> 
>> VMS date/time formats are much more readable, but the main problem with
>> VMS timekeeping is that it doesn't have a local timezone offset from a base
>> GMT/UTC timepoint built into it.
>
> What is SYS$TIMEZONE_DIFFERENTIAL then?
>

A joke. At least when compared to Unix.

In Unix, all timestamps are based on GMT/UTC and the user's timezone is
just an attribute of the user's process, which is the system timezone by
default but can be changed by the user. Different processes can have
different timezones and none of this affects what timestamp is actually
written to the filesystem when the file changes.

VMS commands have no support for showing the active timezone.
Compare the output of the Linux date command with $ SHOW TIME.

Compare the output of the Linux "ls --full" command with $ DIR/FULL.
Note out the Linux command shows the timezone, and note how the timezone
changes for each file depending on whether DST was active or not when the
file was last modified.

Simon.

-- 
Simon Clubley, clubley at remove_me.eisner.decus.org-Earth.UFP
Walking destinations on a map are further away than they appear.