z/VM: CP Commands and Utilities Reference - z/VM - IBM

DEFINE DEVICE / IODEVICE
158 z/VM: CP Commands and Utilities Reference
your system, you must first dynamically define one or more control units for
that device (if they do not already exist) and one or more channel paths (if
they do not already exist).
If you need to physically define any channel paths, control units, or devices,
use the following commands in the following order:
a. To define channel paths, use the DEFINE CHPID or PATH command. (See
page 124.)
b. To define control units, use the DEFINE CU or CNTLUNIT command. (See
page 149.)
c. To define devices, use the DEFINE DEVICE or IODEVICE command.
If you do not define the channel paths, control units, and devices correctly and
in the proper order, CP will issue appropriate error messages.
2. Before you add a new device to the system, you should decide whether you
want CP to immediately initialize that device. If CP initializes a new device
when you add it to the system, you can begin using that device immediately. If
CP does not initialize the new device, you must vary the device online using
the VARY (real device) command (see page 1710) before anyone can use that
device.
3. To display whether CP initializes new real devices as they are added to a
running system, use the QUERY NEW_DEVICES command. (See page 891.)
4. To define or change the way CP initializes new real devices as they are added
to a running system:
v During initialization, use the ENABLE or DISABLE
NEW_DEVICES_INITIALIZED_WHEN_ADDED operands of the FEATURES
statement in your system configuration file. For more information, see the
z/VM: CP Planning and Administration book.
v After initialization, use the SET NEW_DEVICES command. (See page
1301.)
5. To change whether CP uses the sense ID information at device initialization,
use the SENSED or NOTSENSED operands of the SET DEVICES command.
(See page 1241.)
6. After successfully entering this command, you will have changed the software’s
view of the I/O configuration and part of the hardware’s view: the active I/O
configuration in the hardware system area (HSA). You should also change the
other part of the hardware’s view: the active I/O configuration data set (IOCDS)
file on the support element (SE) hard disk.
To change the IOCDS file on the SE hard disk, you must:
a. Update the IOCP source file.
b. Run the IOCP utility (see page 1849) against the updated IOCP file. If the
IOCP utility runs without errors, it downloads the new IOCDS file to the SE
hard disk.
c. Issue the SET IOCDS_ACTIVE command(see page 1258) to make the
new IOCDS file the active file that the processor will use during the next
power-on reset (POR).
7. For more information about defining real devices in your I/O configuration, see
z/VM: I/O Configuration.
8. To change the definition of an existing device on the system, use the MODIFY
DEVICE or IODEVICE command. (See page 610.)
9. To delete an existing device on the system, use the DELETE DEVICE or
IODEVICE command. (See page 223.)