UPDATE DEVCLASS (Update a 3590 device class for z/OS media server)

Use this command to update a device class that you defined to use a z/OS® media server to access 3590 devices. The device class that targets storage for the z/OS media server requires a library definition of type ZOSMEDIA.

Privilege class

To issue this command, you must have system privilege or unrestricted storage privilege.

Syntax


                                      (1) (2)   
>>-UPDate DEVclass--device_class_name--------------------------->

>--+--------------------------+--+------------------------+----->
   '-LIBRary--=--library_name-'  '-FORMAT--=--+-DRIVE---+-'   
                                              +-3590B---+     
                                              +-3590C---+     
                                              +-3590E-B-+     
                                              +-3590E-C-+     
                                              +-3590H-B-+     
                                              '-3590H-C-'     

>--+----------------------+--+-------------------------+-------->
   '-ESTCAPacity--=--size-'  '-COMPression--=--+-Yes-+-'   
                                               '-No--'     

>--+----------------------------+--+-----------------------+---->
   '-MOUNTRetention--=--minutes-'  '-MOUNTWait--=--minutes-'   

>--+---------------------------+--+------------------------+---->
   '-MOUNTLimit--=--+-DRIVES-+-'  '-EXPiration--=--yyyyddd-'   
                    +-number-+                                 
                    '-0------'                                 

>--+--------------------+--+------------------------------+----->
   '-RETention--=--days-'  '-PROtection--=--+-No--------+-'   
                                            +-Yes-------+     
                                            '-Automatic-'     

>--+--------------------+--------------------------------------><
   '-UNIT--=--unit_name-'

Notes:

You must specify at least one optional parameter on this command.
You cannot update the PREFIX parameter with this command. You must create a device class with the value that you require for the PREFIX parameter.

Parameters

device_class_name (Required)

Specifies the name of the device class to be updated.

LIBRary

Specifies the name of a library that was defined with the LIBTYPE=ZOSMEDIA parameter. The library and the tape drives that can be used by this device class are controlled by the z/OS media server.

This parameter is optional.

For information about defining a library, see the DEFINE LIBRARY command.

FORMAT

Specifies the recording format to be used when data is written to sequential access media. This parameter is optional.

The following table lists the recording format options for 3590 devices:

Table 1. Recording formats for 3590
Format	Description
3590B	Uncompressed (basic) format
3590C	Compressed format
3590E-B	Uncompressed (basic) format, similar to the 3590B format
3590E-C	Compressed format, similar to the 3590C format
3590H-B	Uncompressed (basic) format, similar to the 3590B format
3590H-C	Compressed format, similar to the 3590C format
Note: If the format uses the tape drive hardware compression feature the actual capacity can increase, depending on the effectiveness of compression.

ESTCAPacity

Specifies the estimated capacity for the sequential access volumes that are categorized by this device class. This parameter is optional.

You can specify this parameter if the default estimated capacity for the device class is inaccurate because of compression of data. The value does not determine the amount of data stored on the volume. The server uses the value to estimate the usage before a volume is filled. After a volume is full, the actual amount of data stored on the tape is used for the usage calculation.

Specify the value as an integer with one of the following unit indicators: K (KB), M (MB), G (GB), or T (TB). For example, specify that the estimated capacity is 9 GB with the parameter ESTCAPACITY=9G. The smallest value that is accepted is 100 KB (ESTCAPACITY=100K).

COMPression

Specifies whether file compression is used for this device class. This parameter is optional.

You can specify one of the following values:

Yes: Specifies that the data for each tape volume is compressed.
No: Specifies that the data for each tape volume is not compressed.

MOUNTRetention

Specifies the number of minutes that an idle tape volume is retained before it is dismounted. The time span for mount retention begins after the idle timeout period has expired. This parameter is optional. Specify a number, 0 - 9999.

This parameter can improve response time for sequential access media mounts by leaving previously mounted volumes online.

MOUNTWait

Specifies the maximum number of minutes that the z/OS media server waits for a volume mount. If the mount request is not satisfied within the specified time, the mount request fails. If a device is successfully allocated and the device-open request does not complete within the specified time, the device-open request ends and the mount request fails.

This parameter is optional. Specify a number, 1 - 9999.

Restriction: If the library that is associated with this device class is external (LIBTYPE=EXTERNAL), do not specify the MOUNTWAIT parameter.

MOUNTLimit

Specifies the maximum number of sequential access volumes that can be simultaneously mounted for the device class. This parameter is optional.

If you plan to use the simultaneous-write function, ensure that sufficient drives are available for the write operation. If the number of drives needed for a simultaneous-write operation is greater than the value of the MOUNTLIMIT parameter for a device class, the transaction fails.

You can specify one of the following values:

DRIVES: Specifies that every time a mount point is allocated, the number of drives that are defined and online in the library is used to calculate the true value.
number: Specifies the maximum number of drives in this device class that are used concurrently by the server. This value must never exceed the number of drives that are defined and online in the library that services this device class. You can specify a number, 0 - 4096.
0 (zero): Specifies that no new transactions can gain access to the storage pool.

EXPiration

Specifies the expiration date that is placed on the tape labels for this device class. This parameter is optional.

Specify the date when the server no longer requires the tape. The server does not use this information, but this information is passed to the z/OS media server for use by z/OS or tape management systems.

Specify the expiration date using the format, yyyyddd (four digits for the year and three digits for the day). For example, January 7, 2014 is specified as 2014007 (the seventh day of year 2014).

If you specify the EXPIRATION parameter, you cannot specify the RETENTION parameter.

RETention

Specifies the number of days to retain the tape. This parameter is optional.

Specify the number of days (1 - 9999) that the server is expected to use the tape. The server does not use this information, but this information is passed to the z/OS media server for use by z/OS or tape management systems.

If you specify the RETENTION parameter, you cannot specify the EXPIRATION parameter.

Tip: You can specify a value of zero for this parameter. However, do so only if you also want to specify a value for the EXPIRATION parameter. You cannot specify a value for the EXPIRATION parameter if you specify a non-zero value for the RETENTION parameter.

PROtection

Specifies whether the RACF® program, if installed, protects volumes that are assigned to this device class. If protection is provided, RACF profiles are created when volumes are first used. This parameter is optional. You can specify one of the following values:

No

Specifies that the RACF program does not protect volumes that are assigned to this device class.

Yes

Specifies that the RACF program protects volumes that are assigned to this device class. RACF profiles are created for volumes when the server first uses the volumes, but the profiles are not deleted when volumes are deleted from the server. Profiles must be manually deleted.

Tip: If sensitive data is stored on volumes that are assigned to this device class, use PROTECTION=YES and manually delete RACF profiles only after tape volumes have been erased.

The profiles that are created for volumes depend on the system RACF settings. The protection that is provided is the same as using PROTECT=YES in JCL. If the RACF program is active and both TAPEVOL and TAPEDSN are inactive, allocation of tapes fails.

Automatic

Specifies that the RACF program protects volumes that are assigned to this device class. RACF profiles are created for volumes when the server first uses the volumes. RACF profiles are deleted when volumes are deleted from the server.

Important: If you specify PROTECTION=AUTOMATIC, when a volume is deleted, its RACF profile is deleted. The volume therefore is no longer protected by the RACF program. The data on these volumes can be accessed by other users.

If you specify PROTECTION=AUTOMATIC, the z/OS media server issues RACROUTE commands to delete profiles when a volume is deleted from the server. The deletion commands that are issued depend on the current system settings for TAPEVOL and TAPEDSN. If the system settings are changed, the z/OS media server might not delete existing profiles.

Do not change the setting to PROTECTION=AUTOMATIC for a device class that was set to PROTECTION=NO. Volumes without profiles might exist and error messages are generated when such volumes are deleted. If a different value for PROTECTION is required, define a new device class.

Profile creation and deletion occur based on the protection setting when the volume is first used and when it is deleted. The server does not attempt to create profiles for volumes that it has already used. If protection is set to AUTOMATIC, the server attempts to delete profiles when volumes are deleted.

See the documentation for the RACF program for details about the TAPEVOL and TAPEDSN settings and the profiles that are created when these settings are active.

UNIT

Specifies an esoteric unit name to specify a group of tape devices that support 3590 tape. This parameter is optional. The unit name can be up to 8 characters.