[TUHS] UNIX turns forty

[Brian S Walden]

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.