HP Support document

The purpose of this advisory is to remind our customers who may have the requirement for storing future timestamps of the limitations of certain timestamp formats.

The original MPE timestamp format was that used by the CALENDAR intrinsic, a 16 bit quantity allowing 9 bits for the day of the year and 7 bits for the year, added to 1900. Since the largest number represented by 7 bits is 127, this format is limited to accurately storing years up to 2027.

The newer HPCALENDAR intrinsic uses a 32 bit quantity, allowing 23 bits for the year, since 1900 and the same 9 bits for the day of the year. This format provides a significantly longer period of timestamp accuracy.

Certain POSIX applications may use the time() function as the basis for timestamps; and may therefore, store timestamps in the format used by time(), which is a 32 bit quantity representing the number of seconds from the epoch 1 January 1970. This format is limited to accurately storing timestamps up to 19 January 2038.

If your applications have a need to create and store future transaction timestamps, HP recommends using HPCALENDAR, HPDATECONVERT, HPDATEDIFF, HPDATEFORMAT or HPDATEOFFSET to ensure they are created correctly.