StorageTek 6 manual Virtual Thumbwheel VTW, Tape Management Interface, HSC Mount Command Support

•The TMS is unsatisfied with the scratch cartridge provided.

-The HSC dismounts the current volume, removes it from the scratch list, and mounts another scratch volume.

Virtual Thumbwheel (VTW)

Virtual thumbwheel is the HSC function that allows read-only access to a cartridge in an ACS. Normally cartridges are stored in the library with the physical cartridge thumbwheel enabled for writing. There are circumstances where it is desirable to allow enforced read-only access to a volume without removing the volume from the LSM, changing the physical thumbwheel, and reentering it.

The HSC may, via the VM HSC Tape Management Interface (TMI) or by operator command, cause a volume to be mounted while instructing the transport to allow read-only access to the volume by simulating that the thumbwheel is in a read-only state. In this virtual thumbwheel mode, the transport ignores the fact that the volume might be physically enabled for writing.

The transport never writes on a cartridge that is physically write-protected.

Tape Management Interface

The TMI utilizes virtual thumbwheel when the PROTECT parameter is specified with MOUNT requests. Refer to the HSC Interface to Tape Management Systems Manual for interface details.

HSC Mount Command Support

The Mount command provides support for virtual thumbwheel. The Readonly operand for the Mount command enables a volume to be mounted with the virtual thumbwheel set to write protect.

Example of Mount Command with Readonly Operand

MOUNT VOL001,B00,,READONLY

Note: Operands for operator commands are positional. In the example above, two commas must follow the drive operand to indicate that the host-id operand is not specified.

Refer to the HSC Operator’s Guide for details on the HSC Mount command.

36VM/HSC 6.0 System Programmer’s Guide

1st ed., 6/30/04 - 312579601