Subject: Re: nore on disk stats
To: None <tech-kern@NetBSD.ORG>
From: der Mouse <mouse@Collatz.McRCIM.McGill.EDU>
List: tech-kern
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.

					der Mouse