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From: firth@sei.cmu.edu (Robert Firth)
Newsgroups: comp.arch,comp.dcom.lans
Subject: Re: Time synchronization in a Distributed Environment
Message-ID: <4383@aw.sei.cmu.edu>
Date: 29 Feb 88 14:31:47 GMT
References: <druhi.2710> <1571@ogcvax.UUCP>
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In article <druhi.2710> aws@druhi.ATT.COM (SteereA) writes:

]  I am looking for articles, references, implementations,
]etc. for solving the problem of keeping N machines within
]a specified time of one another.  I appreciate any and all
]pointers.

In article <1571@ogcvax.UUCP> pase@ogcvax.UUCP (Douglas M. Pase) writes:

]This article may be of some use to you
]
]%A Leslie Lamport
]%T Time, Clocks, and the Ordering of Events in a Distributed System
]%J Communications of the ACM
]%V 21
]%N 7
]%P 558-565
]%D July 1978
]%K lam78

I'd second that.  This is an excellent article on the subject.
However, whereas the first half is generally useful, the second
part - where Lamport talks about real clocks rather than 'logical'
clocks - applies only in the special circumstance that all the
processors are in the same inertial frame of reference. (As the
author indicates in a footnote)

In general, you CANNOT keep two clocks synchronized within an
arbitrary delta, for reasons explained by Einstein these many
years ago.