[Haskell-cafe] Re: Computer time, independent of date

Mauricio briqueabraque at yahoo.com
Sat Jan 10 15:25:37 EST 2009

>> POSIX realtime extensions have been developed to be high reliable.
> (...) However, they offer
> no guarantees on interval measurements, and the correction algorithms
> can cause the measurement of a time interval of an hour or so duration
> to be off by +/- 1 sec, especially within the first few hours after a
> cold boot. (...)

At the start of this thread, my assumption was that
all computers had a 100% reliable tick counter. Well,
this shows I understand nothing about hardware.

My problem is that the equipment I interact with is
supposed to deliver data at a constant rate. Since
I don't know how much its engineers care about
patients, I wanted to be sure not to save wrong
information. It wouldn't matter if the clock is
saying we are on XVII century, as long as 10 seconds
would never be 10.1.

But, as I learned from you, my PC is not to be
considered as a reference. Maybe the right approach
is to ask people who understand hardware if mine is
actually a valid concern.


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