[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Re: An experiment about file timestamp (was: Timestamps jump by one hour when switching timezone)

On Thursday 04 November 2010 15:23:13 Rodolfo Medina wrote:

> Chris Jackson <c.jackson@shadowcat.co.uk> writes:

> > File timestamps are (or at least should be) stored in UTC. It's the

> > display of them that's affected.


> But I did the following experiment: on a computer with system time set to

> UTC, I created a file at 14:43 UTC. Then I copied it via rsync and

> ethernet cross cable to another PC with system time set to GMT, one hour

> late respect to UTC. I expected that, on the 2nd PC, the timestamp was

> displayed in the local time, i.e. 15:43; instead, it appears as 14:43 as

> well. (For the copy I used the -t option.)


> So, according with this experiment it is not true that the displayed time

> is in local format.


> I think this may cause serious errors: in fact, when someone read the

> timestamp on the 2nd PC, he would believe that the file were created at

> 14:43 of the GMT time, which is wrong: in fact, it was created at 15:43 GMT

> = 14:43 UTC.


> What do you all think?

That you have not fully understood what UTC is. UTC _is_ GMT. In winter, when we here are on GMT, my local time=UTC. So the statement 15:43 GMT

= 14:43 UTC is, I'm afraid, incorrect. 15:43 GMT = 15:43 UTC, not 14:43 UTC.

I have an idea that there may be some distinction at the atomic level between UTC and GMT. Can anyone enlighten me? Or was the decision to call it UTC in place of GMT purely political?


Reply to: