QDASD or QD

Displays (in message IEE459I) diagnostic information about the status of direct access storage devices and storage control units. You use two classes of QDASD parameters to control the scope of the display: unit selection parameters and dump selection parameters.

Use unit selection parameters to identify the units whose information you want to see. These parameters include [s] [d]ddd and nnn, VOL, MACH, SSID, TYPE, ONLINE, OFFLINE, DEFINED, and CHKFAIL.
DEVSERV returns information about the device that is in the active subchannel set:
- when a 3 or 4-digit device number is specified.
- when VOL unit selection parameter is specified.
For PPRC devices, this is the "primary" device, including failover scenarios.
DEVSERV returns information about the device that is physically configured to the subchannel set s identified by the first digit in the 5-digit device number:
- when a 5-digit device number is specified for the unit selection.
- when MACH, SSID or TYPE unit selection parameter is specified.
This allows DEVSERV commands to a PPRC secondary devices, including when these are configured in alternate subchannel sets.
Use the dump selection parameters, to define the contents of the display. Beyond the basic status information, you can specify which of the following MVS™ system control blocks, and/or what information acquired directly from the following device information buffers, to display in hexadecimal format.
- The system control blocks are UCB, DCE, SSSCB, DPCT and RDFEATS.
  If you specify the parameter NOIO, the display will show only the storage resident information in the MVS control blocks; the command will not issue any I/O to the selected devices.
- The device information buffers are RDC, RCD, and SNSS.
Any hexadecimal information you request appears following the basic status information.

In addition, there is one action parameter, VALIDATE, and one display request parameter, TOTALCYL.

QDASD-specific Unit Selection Parameters

?

Enter the command DEVSERV QDASD,? to view online help text.

sdddd

The device number for which the system is to display information. s indicates the requested subchannel set. [d]ddd is a 3 or 4-digit device number. If the subchannel set number is not 0 and the device number is 3-digit, the 3-digit device number must be preceded by a 0, for example 10800. You can specify any device number that the operating system supports.

When the subchannel set number in s is omitted and none of MACH, SSID nor TYPE unit selection parameter is specified, the device number specified in [d]ddd represents the device that is in the active subchannel set.

When the subchannel set number in s is explicitly specified, the device number specified in dddd represents the device that is physically configured to the subchannel set number in s. This allows DEVSERV commands to a PPRC secondary devices, including when these are configured in alternate subchannel sets.

nnn

The number of DASD devices or units to query. Valid values are from 1 to 256. The default is 1.

VOL=volser

The serial number of the volume whose information DEVSERV will display. The volume must be online to the system where you issue the DEVSERV command.

MACH=mmpp-sssss | XXXX-sssss

A ten-character serial number specifying either the storage control unit or DASD device about which DEVSERV will display information. If you specify XXXX-sssss, the search will be done only on the sssss portion of the number. MACH= will cause an I/O operation for each DASD in the system. To limit the number of I/O operations, specify sdddd and nnn.

SSID=ssid | ALL

Specifies the identification number of the subsystem whose information DEVSERV will display. Valid ssid numbers are from 1 to FFFF.

SSID=ssid will cause an I/O operation for each DASD in the system. To limit the number of I/O operations, specify sdddd and nnn. The only devices displayed are in the same control unit and the same subchannel set if the control unit has multiple subchannel sets defined and sdddd,nnn is specified.

SSID=ALL requests a display of information for all DASD devices that support the RCD (Read Configuration Data) command.

CHPID=chpid

Specifies CHPID to access DASD. This allows DEVSERV to obtain DASD information through specific I/O path. If there is miscabling, DEVSERV might see different information from different CHPID's.

TYPE=type | ALL

Specifies the type of DASD or storage control unit about which DEVSERV will display information. Valid type values are 3380 and 3390. TYPE=ALL causes the system to display information for all DASD devices that meet all other selection criteria. TYPE= will cause an I/O operation for each DASD in the system. To limit the number of I/O operations, specify sdddd and nnn.

ONLINE or ON and OFFLINE or OFF

See the basic status parameters, above.

DEFINED

Displays information about all DASD units defined in the current I/O configuration that meet all other selection criteria. The display contains information based on the existence of unit addresses (UCBs) for DASD type devices, and not on the existence of physical devices. Therefore, the display may contain information even for unit addresses that have no accessible physical devices, or for which an accessible physical device type is inconsistent with the defined device type.

CHKFAIL

Directs the system to display information about a device with a status that is inconsistent between the MVS control blocks and the device. This parameter requires a unit address with a physical device attached to it. CHKFAIL will cause an I/O operation for each DASD in the system. To limit the number of I/O operations, specify sdddd and nnn.

VALIDATE

Uses status information acquired directly from a device to correct inconsistent extended function status information maintained in host processor storage. VALIDATE has no effect if the unit address has no physical device attached.

TOTALCYL

Accumulates device capacities during the scan. Valid track formats are 3380, 3390, and 9345. For each valid track format, the total capacity for all accessible devices will appear at the end of the DEVSERV QDASD display.

RDFEATS

Displays (via message IEE459I) the data in the MVS software control block. If there is an inconsistency between the software and hardware, RDF appears in the EFC result line of the message IEE459I. The DS QD,sdddd,VALIDATE command can correct the inconsistency. If a LIC (microcode) upgrade has occurred, the feature table might be inconsistent with the software control block. Issue the VALIDATE parameter to refresh the control block.

ATTRIBUTE or ATTR

Displays the device attributes.

QDASD Dump Selection Parameters

Parameters that are only valid when (a) specifying sdddd, and nnn has a value of 1, or (b) when specifying the VOL=volser parameter. Dump selection parameter information appears in hexadecimal format. The parameters are:

UCB       unit control block
DCE       device class extension block (of the UCB)
SSSCB     storage subsystem control block
RDFEATS   feature table control block
DPCT      device performance characteristics table
RDC       read device characteristics
RCD       read configuration data
SNSS      sense subsystem status
NOIO      no input/output requests

NOIO prevents I/O requests and allows a display only of storage resident information. All other dump selection parameters cause I/O operations.