Subject: Re: non-512-byte-sector devices vs. UBC
To: Christoph Badura <>
From: Erik E. Fair <>
List: tech-kern
Date: 06/13/1999 16:07:43
At 14:40 -0700 6/13/99, Christoph Badura wrote:
> (Chuck Silvers) writes:
>>on a related note, it does seem odd that the current buf interface has
>>the offset of the i/o (b_blkno) in sectors, but the size of the i/o
>>(b_bcount) in bytes.  it would be more consistent for both offset and size
>>to have the same units.  or are there devices that can read partial
>>sectors, but only at the beginning of a sector?
>Tape drives do that.

But no one uses tape drives through the block device; everyone uses the
character ("raw") device, which does not go through the buffer cache.