On Thu, 06 Jan 2011 16:10:36 -0500 (EST), Richard Troth wrote:
>
> The "problem" is that one cannot boot from an unpartitioned CKD disk
> (LDL) even though one can boot from an unpartitioned FBA disk.
> Partition tables are not required for other disks and bootstraps.  Why
> should they be required for mainframe disks and bootstraps?

The Linux kernel does not consider an LDL-format disk to be "unpartitioned".
If you format a disk with dasdfmt using "-d ldl" (and other appropriate
parameters), then the disk has been implicitly partitioned, as far as
the Linux kernel is concerned.  Assuming CKD DASD, the implicit partition
will begin with the fourth physical block.  (The first two blocks are
reserved for IPL records, the third block is the volume label.)

I haven't tested your exact scenario, but here's what I have tested.
I have a Linux machine that runs in a virtual machine under z/VM.
It has four disks, as follows:

device  block        mount
number  special      point
        file
------  -------      -----
0200    /dev/dasda
        /dev/dasda1  /
0201    /dev/dasdb
        /dev/dasdb1  /boot
0202    /dev/dasdc
        /dev/dasdc1  /home
0203    /dev/dasdd
        /dev/dasdd1  swap

All four of the disks are CMS reserved minidisks.  All of them use
the DIAG driver except 0201, which uses the ECKD driver.  The
boot device is 0201.  Linux is started by

   IPL 0201

It works great.  I've been doing it for years.  What's the problem?

(0201 has to use the ECKD driver because zipl does not support
writing IPL records to a device controlled by the DIAG driver)

--
  .''`.     Stephen Powell
 : :'  :
 `. `'`
   `-

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