Subject: Re: nore on disk stats
To: None <tech-kern@NetBSD.ORG>
From: der Mouse <mouse@Collatz.McRCIM.McGill.EDU>
Date: 11/20/1995 16:36:18
>> Quads are your friends. I sincerely doubt that you'll wrap a quad
>> counter "very quickly" (or even "at all" 8-)...
> If you are talking byte counters they will wrap, you can always
> overflow into a "counter of counters" though.
Let's assume disk bandwidth is 10 megabytes per second. Let's also
assume it's run wide open constantly.
Then a quad counter counting bytes will wrap after
18446744073709551616/10485760=1759218604441.6 seconds. This is a
little over one and a third million years. (About .345% over, for
those sufficiently curious to care.)
That's a killer uptime figure. :-)
I don't think there's any need to worry about overflowing a quad. At
least not soon. It won't overflow until machines with registers as
narrow as 64 bits are ancient dinosaurs.