Mark Post wrote:
> Rick Troth wrote:
> > IBM needs to figure out if they *really* need a custom 'fdisk'
> > in the S390 Tools kit since they clearly will need "normal FDISK"
> > to support SCSI. I would prefer that the FDISK included in
> > Util-Linux be properly patched than to see two versions of it.
> >
> > If there must be two,
> > then it might be wise to rename the newcomer 'fdisk390'.
[...]
> More careful reading ( =:o ) of the thread reveals that s390utils provides
> fdasd, and a symbolic link to that named fdisk. So, the real name doesn't
> conflict, just the link. In the future, the link could be replaced by a
> real module, perhaps just the same as fdisk is now, but enhanced for
> Linux/390. Personally, I would have preferred that fdasd never have
> existed, rather that the fdisk code been upgraded to handle all disk types.
> I still think that is the way to go in the future.
Hmm, I'm not entirely sure about that.
The "fdisk" program on Linux was originally made to be a one-on-one
functional replacement for the equivalent DOS program named "FDISK",
dealing with the IBM PC hard disk partition table format.
These days, the Linux implementation of fdisk appears to also support
some other partitioning schemes, such as BSD/SUN and SGI.
Other Unix systems have had tools to manipulate their own disk
partition tables, going by various names, such as "disklabel",
"mkpart", "parted", etc.
The PC platform has added one level of confusion to the partition
table story in that several UNIX implementations took their own
partitioning scheme with them and added it on top of the original
IBM PC partition table, which was primarily used to segregate
different operating systems.
E.g. FreeBSD has both an "fdisk" utility to manipulate the PC
partition table, which is primarily used to give FreeBSD a
partition (named "slice" in this context) in the view of any
other operating systems that might be on there, and a "disklabel"
utility to manipulate its own partition table that is used to
define the various partitions used for different filesystems & such.
Linux, not having a non-PC history behind it, did things a bit
differently and used the PC partition table as its "native"
partition table on PC platforms.
The situation with Linux/390 DASD is obviously entirely different,
with Linux partitions being defined as items in the platform's
native VTOC table. There is no relation at all with the IBM PC
partition table scheme.
Now, since Linux/390 also supports SCSI disks these days, it
could very well deal with disks with PC, Sun, BSD or SGI
partition tables, and thus the "solution" to exclude the
existing fdisk program from the S/390 platform, as suggested,
is clearly wrong. The conclusion must be that the link
from fdisk to fdasd was a mistake, perhaps borne out of a
desire to make Linux on S/390 look just like Linux on PC.
Whether one wants to add IBM DASD VTOC partitioning support
to fdisk, I have to wonder. This is a fundamentally different
scheme, and there is no interaction whatsoever between them.
My choice would be to keep it separate, choose a fitting name
from a wider Unix context, rather than the current "fdasd" name,
which contrasts it to "fdisk" in a narrow PC Linux context, and
make sure there is no confusion with the fdisk program.
Does anyone know what these tools on UTS and/or AIX/370 were called?
--
Willem Konynenberg <[EMAIL PROTECTED]>
Konynenberg Software Engineering
