Blocksizes on ISC UNIX System V

[dirk]

On some INTERACTIVE ports to the iAPX386 there is the possibility to
format the disk either with 512 or 1024 bytes sektors. But if you
look at the /usr/include/sys/fs/s5param.h header you'll find that
the system buffer (SBSIZE) is 1024 bytes. That's ok but if you include
the /usr/include/stand.h header, you'll see that there is a define
for the FsTYPE 1 (512 byte sektor/ 512 byte system buffer). The
actual FsTYPE used is 2.

? Is it just a bug in the stand.h header ?
? Who changes the header when using 1024 byte sektors ?

Later on, in /usr/include/sys/buf.h the struct buf contains a entry
b_bcount which contains the number of requested bytes. As written in
the device driver manual, this will be at least one logical block.
The logical block is discribed as 512 bytes in the manual. 

? Is the description 'logical block' just another constant inside the
  system ? Is there any relationship between 'logical block', BSIZE and
  SBUFSIZE ?

thanks and cu,
dirk :-)