RFC 003: Timestamp Format#

  • Status: Final

  • Submit Date: 2017-05-30

  • Authors: SECoP committee

  • Type: Issue

  • PR:

  • Version: 1.0

Summary#

Which format should timestamps in value qualifiers take?

Issue text#

Proposals for the timestamp format are:

ISO time format#

A date+time string in ISO format like “2017-06-21T13:30:01.123456+02:00”

The fractional seconds are optional, but the timezone has to be given. Z is allowed instead of +00:00.

Advantages:

  • human readable

Disadvantages:

  • needs more conversion efforts, as the time is internally already stored as numbers on mosts systems (supporting math operations)

  • although the ISO standard is clearly defined, there is a risk that time zones and daylight saving time is not handled properly

Fractional Unix Time#

Seconds since 1970-01-01T00:00:00+00:00, represented as a number. When converted to a IEEE double, a resolution of 1 usec can be kept for dates up to 2112.

Advantages:

  • if a double is used as an internal representation, no conversion is needed. using a double as an internal time representation has the advantage, that math operations can be done for free.

  • relative times for systems with no synchronized clock can be represented easily

Disadvantages:

  • not human readable (or at least not easily: time differences in seconds are still visible)

Discussion#

  1. Human readibility was judged less important than easy implementaion by the majority.

  2. Implementing relative times is also easier.

Decision#

At the meeting in Berlin (2017-05-30) the attendes decided for “Fractional Unix Time”. The resolution of the timestamp depends on the hardware, but must be at least one second.