Block size problem

Block size problem

[Jan Kara]

  Hello,

  my friend has a following problem: He has FAT filesystem on MO disk
  and computer with SCSI drive reading MO disk. The problem is that
  smallest blocksize supported by the driver is larger than 512 bytes
  which FAT needs. What is the right solution? Copying the device and
  loopback mounting is always possible but it's not nice...  
  Should I fix the driver to support 512 byte sectors (I'm not sure if
  SCSI drivers are supposed to support that)? Another solution I though
  about is creating loopback directly to device but loopback device
  supports only blocksize same as underlying device... So do you think
  it would be nice/useful if loopback device supported any blocksize?

  								Honza
-- 
Jan Kara <jack@suse.cz>
SuSE CR Labs

Re: Block size problem

[OGAWA Hirofumi]

Jan Kara <jack@suse.cz> writes:

>   Hello,
> 
>   my friend has a following problem: He has FAT filesystem on MO disk
>   and computer with SCSI drive reading MO disk. The problem is that
>   smallest blocksize supported by the driver is larger than 512 bytes
>   which FAT needs. What is the right solution?

AFAIK, since originally FAT driver also isn't supporting blocksize
smaller than device sector size, I think he should use blocksize
larger than device sector size.

for example,

    $ mkdosfs -S 2048 /dev/xxx

>   Another solution I though about is creating loopback directly to
>   device but loopback device supports only blocksize same as
>   underlying device... So do you think it would be nice/useful if
>   loopback device supported any blocksize?

Since it isn't the problem of only FAT, I think it would be useful.
-- 
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>

Re: Block size problem

[Jan Kara]

> Jan Kara <jack@suse.cz> writes:
> 
> >   Hello,
> > 
> >   my friend has a following problem: He has FAT filesystem on MO disk
> >   and computer with SCSI drive reading MO disk. The problem is that
> >   smallest blocksize supported by the driver is larger than 512 bytes
> >   which FAT needs. What is the right solution?
> 
> AFAIK, since originally FAT driver also isn't supporting blocksize
> smaller than device sector size, I think he should use blocksize
> larger than device sector size.
> 
> for example,
> 
>     $ mkdosfs -S 2048 /dev/xxx
  Sadly that isn't a choice because disks are created by EWSD phone
  exchange...
  
> >   Another solution I though about is creating loopback directly to
> >   device but loopback device supports only blocksize same as
> >   underlying device... So do you think it would be nice/useful if
> >   loopback device supported any blocksize?
> 
> Since it isn't the problem of only FAT, I think it would be useful.

								Honza
-- 
Jan Kara <jack@suse.cz>
SuSE CR Labs