On 2025-02-20 04:17 PM, Guy Harris wrote:
On Feb 20, 2025, at 12:37 PM, Brooks Harris via tz<tz@iana.org> wrote:
On 2025-02-20 02:45 PM, Paul Eggert via tz wrote:
In other words, users don't really want true System V compatibility. They just want to keep using the same name for US eastern time. That's true for most users. But not necessarily for special cases.
For example, some professional video facilities might find it better to ignore DST shifts to avoid discontinuities in the SMPTE video timecode, which cannot tolerate a DST shift in some cases, essentially choosing to run "permanent stand time". Yes, the display time would not match the local wall clock in summer time, but that is less important than continuous uninterrupted time. EST5EDT and the others (PST8PDT and such) give administrators that option. What option? EST5EDT isn't permanent stand(and) time, it supports DST, following some unspecified-by-the-setting rules.
If you want *permanent standard time* for the UTC-5:00 time zone, that'd be "EST5", which does *not* correspond to a tzdb file; it works as a TZ setting because the tz code parses TZ POSIX/SV-style if it doesn't correspond to a file. Right. My mistake, I meant EST5 and the like.