Updating a 4mm Device Class

To update a device class, first complete the following fields and then click Finish, or click Cancel to end the task.

Recording Format

Select the recording format to be used when writing data to volumes in this device class.

Drive Specifies that Tivoli Storage Manager selects the highest format that can be supported by the drive on which a volume is mounted. The default is Drive.
DDS1 Specifies that Tivoli Storage Manager writes data using the DDS-1 recording format for 4mm tapes, without compression. This format results in an uncompressed cartridge capacity of 1.3GB on 60 meter tape or 2GB on 90 meter tape. This format only applies to 60 and 90 meter tapes.
DDS1C Specifies that Tivoli Storage Manager writes data using the DDS-1 recording format for 4mm tapes, with compression enabled. This results in a cartridge capacity of approximately 1.3GB on a 60 meter tape or 2GB on a 90 meter tape. However, this format uses the tape drive hardware compression feature, so the actual capacity may be greater, depending on the effectiveness of compression. This format only applies to 60 and 90 meter tapes.
DDS2 Specifies that Tivoli Storage Manager writes data using the DDS-2 recording format for 4mm tapes, without compression. This format results in a cartridge capacity of 4GB on 120 meter tape. This format only applies to 120 meter tape.
DDS2C Specifies that Tivoli Storage Manager writes data using the DDS-2 recording format for 4mm tapes, with compression. This format results in a cartridge capacity of approximately 8GB on 120 meter tape. However, this format uses the tape drive hardware compression feature, so the actual capacity may be greater, depending on the effectiveness of compression. This format only applies to 120 meter tape.
DDS3 Specifies that Tivoli Storage Manager writes data using the DDS-3 recording format for 4mm tapes, without compression. This format results in a cartridge capacity of 12GB on 125 meter tape. This format only applies to 125 meter tape.
DDS3C Specifies that Tivoli Storage Manager writes data using the DDS-3 recording format for 4mm tapes, with compression. This format results in a cartridge capacity of approximately 24GB on 125 meter tape. However, this format uses the tape drive hardware compression feature, so the actual capacity may be greater, depending on the effectiveness of compression. This format only applies to 125 meter tape.

Library Name

Select the name of the library that contains the tape drives used by this device class.

Mount Limit

Enter the maximum number of volumes that can be simultaneously mounted for the device class. This value can be any number from 0 to 256.

The following are possible values:

Drives Specify the number of drives defined and online in the library. The default is Drives.
value Specify the maximum number of drives used concurrently. This value must never be allowed to exceed the number of drives defined and online in the library. For external libraries, specify the number of drives for the library.
0 The value of zero prevents new transactions from gaining access to the storage pool. 

Mount Retention Period

Enter the amount of time, in minutes, to retain an idle volume before dismounting it.

Tape Volume Prefix

Enter the high level qualifier of the file name that the server writes into the media labels in the Prefix field. For each volume assigned to this device class, Tivoli Storage Manager uses this prefix to create the data set name.

Example: AB.CD2.E

Estimated Capacity

Enter the estimated capacity for the volumes assigned to this device class. You do not need to specify an estimated capacity unless the drives perform data compression, or you have volumes of nonstandard size. The value must be an integer followed by a scale factor.

Scale factors and their meanings are:

K Kilobyte
M Megabyte
G Gigabyte

Mount Wait Period

Enter the maximum length of time, in minutes, to wait for a volume to be mounted in a manual library.