tree 66dfc19e2164a6a30d19b958ccf4e4a5d210c8d8
parent f9a28f7bc5225af476f8d4bb669038da8801b7c4
author Stefan Weinhuber <wein@de.ibm.com> 1238077427 +0100
committer Martin Schwidefsky <schwidefsky@de.ibm.com> 1238077445 +0100

[S390] dasd: add large volume support

The dasd device driver will now support ECKD devices with more then
65520 cylinders.
In the traditional ECKD adressing scheme each track is addressed
by a 16-bit cylinder and 16-bit head number. The new addressing
scheme makes use of the fact that the actual number of heads is
never larger then 15, so 12 bits of the head number can be redefined
to be part of the cylinder address.

Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>