Article View: comp.protocols.time.ntp
Article #864Re: uVAXII clock
From: Louis A. Mamakos
Date: Thu, 19 Nov 1992 13:56
Date: Thu, 19 Nov 1992 13:56
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In article <1992Nov18.140049.199016@rrz.uni-koeln.de> schittel@geo.Uni-Koeln.DE (Christoph Schittel) writes: >Under VMS a uVAX keeps time very well. What about >Ultrix on uVAX? Is it a good idea to use an old >uVAXII (in constant temperature environment) as stratum >1 server? Given that a MicroVAX-II CPU's clock only has a resolution of 20ms, this is some new interpretation of "keeps time very well." The problem with the MicroVAX-II interval timer (which is used to keep time on the running system by periodically generating interrupts) is that you cannot determine the time remaining until the next interval timer interrupt, so you stuck with the resolution that corresponds to how frequently the interval timer is programmed to generate interrupts. This is (on 4.3 BSD systems) 20ms. While it may be that the clock doesn't drift very badly, the fact that the resolution is only 20ms somewhat precludes it as a good source of time for others. louie
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Path: arc1-ca.pugleaf.net!sparky!uunet!spool.mu.edu!darwin.sura.net!haven.umd.edu!ni.umd.edu!sayshell.umd.edu!louie From: louie@sayshell.umd.edu (Louis A. Mamakos) Newsgroups: comp.protocols.time.ntp Subject: Re: uVAXII clock Date: 19 Nov 1992 13:56:17 GMT Organization: University of Maryland, College Park Lines: 23 Distribution: inet Message-ID: <1eg6e1INNnr4@ni.umd.edu> References: <1992Nov18.140049.199016@rrz.uni-koeln.de> NNTP-Posting-Host: sayshell.umd.edu