From: paul.winalski@gmail.com (Paul Winalski)
Subject: [TUHS] Sleep()y musings
Date: Wed, 7 Mar 2018 13:54:32 -0500 [thread overview]
Message-ID: <CABH=_VTO7sdgGypp3U7zQoWdJ3HsGUUjrk-6_Rf5VE5gyNGD7g@mail.gmail.com> (raw)
In-Reply-To: <CAC20D2NLhbLg3s+VRD0P3U1j7W_HcZsEEOTgd998eb0e-z3YRg@mail.gmail.com>
On 3/6/18, Clem Cole <clemc at ccc.com> wrote:
>
> In the end, BSD4.2 ended up with new time
> calls because of that community and started doing things in 100th of second
> - which again IIRC was the best the Vax could do.
>
When all else fails, RTFM. :-)
According to the VAX Architecture Reference Manual (1987), the
Interval Clock Register, which is used by OSes to keep track of real
time, is a 32-bit unsigned value incremented at 1-microsecond
(0.000001 second) intervals.
VAX also has a Time-of-Year Clock Register (colloquially called the
TOY clock), a 32-bit unsigned value whose LSB represents a resolution
of 10 milliseconds (0.01 second). All VAX models except the
VAX-11/730 provided battery backup for the TOY clock so that it
continued to operate even when the system was powered off. A VAX can
thus be powered off for about 497 days and still remember the
date/time.
I think Clem was remembering the TOY clock. It would be the Interval
Clock Register that was used by BSD to implement sleep() and other
time-related services.
-Paul W.
next prev parent reply other threads:[~2018-03-07 18:54 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-06 18:11 Noel Chiappa
2018-03-06 20:53 ` Clem Cole
2018-03-06 21:39 ` Paul Winalski
2018-03-07 16:33 ` Michael Kjörling
2018-03-07 18:54 ` Paul Winalski [this message]
-- strict thread matches above, loose matches on Subject: below --
2018-03-08 3:39 Rudi Blom
2018-03-06 17:58 Dave Horsfall
2018-03-08 21:50 ` Dave Horsfall
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CABH=_VTO7sdgGypp3U7zQoWdJ3HsGUUjrk-6_Rf5VE5gyNGD7g@mail.gmail.com' \
--to=paul.winalski@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).