You need to select a tape drive only when you are not going to use the default tape drive. All tape commands use the currently selected tape drive; if none is selected, the default tape drive is used.
To select a tape device other than the default and attach it to your process, use the T-SELECT command to specify the logical tape unit.
Selecting a Tape Drive for an Account
Although tape unit 0 is automatically selected by default when a user logs onto the system, it is not, however, attached to the user’s process. The T-SELECT command selects one or more tape units and attaches them to your current process. The tape drive may not be attached to any other process in order for you to attach it to yours.
These tape units remain selected until the user either logs off or selects another tape unit. They remain attached until the user logs off or detaches them with the T-DET command.
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NOTE |
You must have at least SYS1 privileges to use T-SELECT. |
The T-SELECT command can be used to chain two or more tape drives to a single process. A series of 1/4-inch, 4mm DAT, 8mm, or floppy tape drives can be chained together and selected for the same process. This allows multireel tape operations to be performed without operator intervention.
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CAUTION |
Each of the tape units must be assigned to tape drives of the same type and use the same format. |
Tape operations using this set proceeds from tape unit 0 to tape unit 2. A second set of reels can then be mounted, and operations returns from tape unit 2 to tape unit 0. Tape operations can then proceed, going around the chain again in the same order.
Selecting a Remote Floppy Drive
When you use T-SELECT to select a remote floppy device, the client's or Workstation's PC floppy drive replaces the A: in the mvBase Server's tape device table. The client may now use this floppy drive, rather than using the floppy drive located on the Server. Tape commands on the remote floppy function normally. When the user detaches from the remote floppy, the path to a: is restored.
You can create multiple aliases for a single floppy tape device. Consequently, while one user is T-ATTached to the floppy device, another user can T-ATTach to the same device using a different alias. However, the second user receives the DEVICE NOT READY message if attempting to access the floppy tape device. This same message displays if the device is in use by another program running on the host operating system.
See Also