22 May
2009
22 May
'09
2:39 a.m.
On 20 May 2009, at 05:56, Derek Peschel wrote:
Interesting question! And related questions -- When
did the current
start of the epoch get chosen? Were there any false starts or early
changes? (I seem to recall reading about one change, moving forward
by a year.) And were there ever any dates in the system that couldn't
be correctly recorded, because the epoch started too late?
The current epoch was choose for the 4th edition, the man page date
is 8/5/73. The first edition's epoch was 00:00:00, Jan. 1, 1971.
This can be obtained from the time(2) man page. Here they are parapharsed,
I like that epoch changed from the second to thrid editions, but the
man page date did not; and the "bugs" line from the 3rd edition is memorable.
v1:
DATE: 11/3/71
DESCRIPTION: time returns the time since 00:00:00, Jan. 1, 1971, measured in sixtieths of
a second.
BUGS: The chronological-minded user will note that 2**32 slxtieths of a seeond is only
about 2.5 years.
v2:
DATE: 3/15/72
DESCRIPTION: time returns the time since 00:00:00, Jan. 1, 1971, measured in sixtieths of
a second.
BUGS: The chronological-minded user will note that 2**32 slxtieths of a seeond is only
about 2.5 years.
v3:
DATE: 3/15/72
DESCRIPTION: time returns the time since 00:00:00, Jan. 1, 1972, measured in sixtieths of
a second.
BUGS: The time is stored in 32 bits. This guarantees a crisis every 2.26 years.
v4:
DATE: 8/5/73
DESCRIPTION: time returns the time since 00:00:00 GMT, Jan. 1, 1970, measured in
seconds.