[time-nuts] A milestone approaches

Peter Vince petervince1952 at gmail.com
Fri Jul 14 08:30:33 UTC 2017


Good morning all - I hope you enjoyed the Unix 1.5 billion parties?  An
ex-colleague who used to work on VAX computers has just sent me this
related message:


OpenVMS also has something to say about time:

.
OpenVMS represents system time as the 64-bit number of 100ns intervals
 since midnight preceding November 17, 1858, which is the start of Modified
Julian Day numbering.
.
.
This 100 nanosecond granularity implemented within OpenVMS and the 63-bit
absolute time representation (the sign bit indicates *absolute time* when
clear and *relative time* when set) should allow OpenVMS trouble-free time
computations up to 31-JUL-31086 02:48:05.47. At this instant, all clocks
and time-keeping operations in OpenVMS will suddenly fail, since the
counter will overflow and start from zero again.
.
.
You may have to reset your oven timer after this point . . .


     Peter



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