[src/netbsd-2-0]: src/lib/libc/time Pull up revision 1.8 (requested by kleink...

[he <he%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/98ff28f31f1a
branches:  netbsd-2-0
changeset: 561383:98ff28f31f1a
user:      he <he%NetBSD.org@localhost>
date:      Tue Jun 15 22:02:07 2004 +0000

description:
Pull up revision 1.8 (requested by kleink in ticket #407):
        Update to tzcode2004a.

diffstat:

 lib/libc/time/Theory |  50 ++++++++++++++++++++++++++++++++++++++++++++++++--
 1 files changed, 48 insertions(+), 2 deletions(-)

diffs (68 lines):

diff -r 963a1b28024e -r 98ff28f31f1a lib/libc/time/Theory
--- a/lib/libc/time/Theory      Tue Jun 15 22:02:01 2004 +0000
+++ b/lib/libc/time/Theory      Tue Jun 15 22:02:07 2004 +0000
@@ -1,5 +1,5 @@
-#      $NetBSD: Theory,v 1.7 2003/12/20 00:12:05 kleink Exp $
-@(#)Theory     7.14
+#      $NetBSD: Theory,v 1.7.2.1 2004/06/15 22:02:07 he Exp $
+@(#)Theory     7.15
 
 
 ----- Outline -----
@@ -8,6 +8,7 @@
        Names of time zone regions
        Time zone abbreviations
        Calendrical issues
+       Time and time zones on Mars
 
 
 ----- Time and date functions -----
@@ -505,3 +506,48 @@
 Source:  H. Grotefend, _Taschenbuch der Zeitrechnung des deutschen
 Mittelalters und der Neuzeit_, herausgegeben von Dr. O. Grotefend
 (Hannover:  Hahnsche Buchhandlung, 1941), pp. 26-28.
+
+
+----- Time and time zones on Mars -----
+
+Some people have adjusted their work schedules to fit Mars time.
+Dozens of special Mars watches were built for Jet Propulsion
+Laboratory workers who kept Mars time during the Mars Exploration
+Rovers mission (2004).  These timepieces look like normal Seikos and
+Citizens but use Mars seconds rather than terrestrial seconds.
+
+A Mars solar day is called a "sol" and has a mean period equal to
+about 24 hours 39 minutes 35.244 seconds in terrestrial time.  It is
+divided into a conventional 24-hour clock, so each Mars second equals
+about 1.02749125 terrestrial seconds.
+
+The prime meridian of Mars goes through the center of the crater
+Airy-0, named in honor of the British astronomer who built the
+Greenwich telescope that defines Earth's prime meridian.  Mean solar
+time on the Mars prime meridian is called Mars Coordinated Time (MTC).
+
+Each landed mission on Mars has adopted a different reference for
+solar time keeping, so there is no real standard for Mars time zones.
+For example, the Mars Exploration Rover project (2004) defined two
+time zones "Local Solar Time A" and "Local Solar Time B" for its two
+missions, each zone designed so that its time equals local true solar
+time at approximately the middle of the nominal mission.  Such a "time
+zone" is not particularly suited for any application other than the
+mission itself.
+
+Many calendars have been proposed for Mars, but none have achieved
+wide acceptance.  Astronomers often use Mars Sol Date (MSD) which is a
+sequential count of Mars solar days elapsed since about 1873-12-29
+12:00 GMT.
+
+The tz database does not currently support Mars time, but it is
+documented here in the hopes that support will be added eventually.
+
+Sources:
+
+Michael Allison and Robert Schmunk,
+"Technical Notes on Mars Solar Time as Adopted by the Mars24 Sunclock"
+<http://www.giss.nasa.gov/tools/mars24/help/notes.html> (2004-03-15).
+
+Jia-Rui Chong, "Workdays Fit for a Martian", Los Angeles Times
+(2004-01-14), pp A1, A20-A21.