The VME supports a set of devices that can be used as tapes to save and restore data from previous Pick implementations. The devices supported depend on the underlying host system.
Tapes must be defined in the registry (see VME Server Configuration in the System Administration Guide) before they can be used.
Once the VME server is started, the tape configuration can be changed with the dev-make and dev-remov TCL commands.
Up to 16 tape devices, numbered from 0 through 15, can be used simultaneously.
Note that when the VME is started, all tape devices configured in the registry are installed automatically. They show in the device list when list-device is executed. When D3 is up and running, the user can use dev-make to add more devices without having to reboot.
All systems support pseudo tapes. There is no (practical) limitation to the size of a pseudo tape. The name of a pseudo tape is a full explicit path name (for example, c:\tmp\backup) or partial name, in which case it is located in the directory specified in the registry by the Root value. If the host file does not exist, it is created the first time the tape is opened (read or write).
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Once a tape is opened by the VME, the device is locked and cannot be accessed by any other application. The open takes place at the first access, not when the device is attached. In other words, doing a set-device does not lock the device. To lock the device, either read or write it or do a t-rew. The device gets unlocked when a t-det is issued. |
The label size of the sequential device may need to be changed, depending where the tape is coming from. By default, the system will assume the label was written inside a 512-byte tape block. Some tape devices will require 50 bytes, 80 bytes, or 16 KB.
For Windows: Windows supports, in addition to pseudo tapes, up to two floppies (A and B) and any tape device that can be used from Windows:
Floppy names are \\.\A: and \\.\B:
Tape devices are named \\.\TAPE0, \\.\TAPE1, and so on
The exact nature of the device is fairly transparent to the VME. The device type code in the registry is for informational purposes only.
See Also