Re: [RFC/PATCH 0/2] support for CMS-formatted disks on the s/390 architecture

[Adam Thornton]

I no longer have easy access to a system with CMS disks either, but I do 
remember that Rick Troth wrote cmsfs for Linux in the first place and I 
think his tool set included a couple of CMS disk images to test 
against.  That might be helpful--although since none of them were images 
of CMS RESERVED disks maybe not.

I think that CMS disks can have a different logical block size than the 
underlying DASD, but I also suspect that case is vary rare.  At any 
rate, the logical block size is in the CMS volume label, and might need 
to be scaled according to what the disk says to make parted happy.  
DIAG250 cares about the CMS block size; directly talking to the disk 
with CCWs doesn't.  I think.  It's been a while since I had to know this.

Anyway, if the patch didn't break anything for existing users it's 
definitely an improvement.

Adam

Jonathan Nieder wrote:
> Hi,
>
> The inimitable Stephen Powell sent something like the two patches
> below to <http://bugs.debian.org/578097>.  It seems that they teach
> the dasd driver in parted to handle CMS-labeled partitions, which are
> a little more flexible and probably more common than the LDL format
> libparted already supports.
>
> Unfortunately, I do not have a specimen to experiment with, so I
> cannot say if my whitespace tweaks and so on broke the patch.
> Stephen, would it be possible to put up an image of a tiny partition
> to try this out with?
>
> The support is for reading only because that is what is most needed.
> I don’t imagine there would be any major technical obstacles to
> teaching parted to write these partitions, too.
>
> Thoughts?
> Jonathan
>
> Stephen Powell (2):
>   dasd: take sector size into account when calculating starting block
>   dasd: add read-only support for CMS labeled minidisks
>
>  NEWS                     |    7 +++++++
>  include/parted/vtoc.h    |   43 +++++++++++++++++++++++++++++++++++++++++++
>  libparted/labels/dasd.c  |   24 ++++++++++++++++++++----
>  libparted/labels/fdasd.c |   15 ++++++++-------
>  4 files changed, 78 insertions(+), 11 deletions(-)
>
>
>
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