Subject: Re: non-512-byte-sector devices vs. UBC
To: None <>
From: Heiko W.Rupp <>
List: tech-kern
Date: 06/08/1999 10:09:29
Chris G. Demetriou wrote:
|Sure, sure, compared to the time it takes to do an I/O a few dozen
|divisions isn't too much, but it becomes more significant if you're
|talking about a cached block, and in either case it does consume CPU
|that could have been used on something else...

But then, the power of 2 case is the "normal" case which is used 90%
of the time. So shifts can be used that are not that expensive.

if (blocksize = powof2)
   use shifts
   go the long way.

In the worst case, the check above could be done through a flag for
each device that is read at mount time from the device and which is then

          See <a href="">NetBSD</a> for a multiplatform OS
id bello = [Dog newWithRace: [Dog getRace: @"Rottweiler"]
                gender: [Viviparous getGender: @"Male"]];
[bello bark: 2];  -- Bjoern Giesler in <6nas1v$g9e$>