From: torek@elf.torek.net (Chris Torek)
Subject: [TUHS] Date madness
Date: Wed, 13 Dec 2017 16:24:35 -0800 (PST) [thread overview]
Message-ID: <201712140024.vBE0OZQC079168@elf.torek.net> (raw)
In-Reply-To: <1513203404.29181.for-standards-violators@oclsc.org>
The 780 had only the Time Of Day Register (mfpr $TODR,reg),
but it covered more than a year's worth of "time of day":
http://h41379.www4.hpe.com/wizard/wiz_1450.html
http://rbur004.github.io/MacVAX/VAX-IPR/IPL_CLOCK.html
so the standard trick was to assume that the computer had
been booted within a year or so, and use the file system time
plus the TODR value to compute the correct time.
Various MicroVAXen may have added CMOS clock chips, and I vaguely
recall dealing wth BCD-encoded time on another VAX, perhaps the
8800. I wrote some clock-chip driver code for the 4BSD SPARC port
and tried to consolidate the general issues of dealing with
multiple chip registers, two and four digit year encoding, BCD vs
decimal, and so on.
Chris
next prev parent reply other threads:[~2017-12-14 0:24 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-13 22:16 Norman Wilson
2017-12-14 0:24 ` Chris Torek [this message]
2017-12-17 16:20 ` Ron Natalie
2017-12-17 18:53 ` Tom Ivar Helbekkmo
2017-12-17 20:07 ` Ron Natalie
2017-12-17 21:24 ` [TUHS] OT: trains [Was: Date madness] Ian Zimmerman
2017-12-17 22:35 ` Dave Horsfall
2017-12-18 13:03 ` Norman Wilson
2017-12-18 16:45 ` Ian Zimmerman
2017-12-19 0:48 ` Dave Horsfall
2017-12-18 16:12 ` Steve Mynott
-- strict thread matches above, loose matches on Subject: below --
2017-12-16 10:50 [TUHS] Date madness Doug McIlroy
2017-12-16 16:11 ` Random832
2017-12-16 17:11 ` Ralph Corderoy
2017-12-13 20:22 Noel Chiappa
2017-12-13 19:12 Doug McIlroy
2017-12-14 3:07 ` Random832
2017-12-15 3:04 ` Random832
2017-12-13 17:16 Noel Chiappa
2017-12-13 18:53 ` Tom Ivar Helbekkmo
2017-12-13 20:46 ` arnold
2017-12-15 16:41 ` Paul Winalski
2017-12-15 17:19 ` Dave Horsfall
2017-12-16 15:45 ` Clem Cole
2017-12-16 3:39 ` Dave Horsfall
2017-12-16 3:45 ` Lyndon Nerenberg
2017-12-17 1:43 ` Dave Horsfall
2017-12-14 3:08 ` Dave Horsfall
2017-12-14 3:13 ` Warner Losh
2017-12-13 16:31 Noel Chiappa
2017-12-13 16:50 ` arnold
2017-12-13 16:08 Noel Chiappa
2017-12-13 16:23 ` arnold
2017-12-13 15:56 Noel Chiappa
2017-12-12 18:31 Noel Chiappa
2017-12-12 18:01 Noel Chiappa
2017-12-12 18:21 ` Warner Losh
2017-12-13 15:07 ` Random832
2017-12-13 17:00 ` Jason Stevens
2017-12-13 17:18 ` Ron Natalie
2017-12-13 18:02 ` Arthur Krewat
2017-12-13 15:39 ` Wolfgang Helbig
2017-12-14 0:57 ` Dave Horsfall
2017-12-14 14:09 ` William Cheswick
2017-12-17 16:19 ` Ron Natalie
2017-12-17 16:33 ` William Cheswick
2017-12-17 17:54 ` Random832
2017-12-17 22:15 ` Dave Horsfall
2017-12-17 22:54 ` Ian Zimmerman
2017-12-16 18:12 ` Wolfgang Helbig
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