Raw ECKD access from zLinux

Since a while the Linux DASD driver has been enhanced to access full ECKD tracks. Basically the following steps are needed:

1. Take the device offline from other System z operating systems
2. get the device online in zLinux 
3. switch the device in raw ECKD mode:
   echo 1 > /sys/bus/ccw/devices/<device ID>/raw_track_access
4. use a program that reads and writes whole tracks (64k) with direct IO like a dd with the respective flags to read or write

More details can be found in the chapter about the DASD driver (search for "raw_track_access") in the "Device Drivers, Features, and Commands" book for the respective distributions, e.g.

• Device Drivers, Features, and Commands on SUSE Linux Enterprise Server 11 SP3 - SC34-2595-03
• Device Drivers, Features, and Commands on Red Hat Enterprise Linux 6.4 - SC34-2597-04
• Device Drivers, Features, and Commands (kernel 3.11) - SC33-8411-22 

This book is really recommended as a reference.