Technical data

Managing Storage Media
9.1 Understanding Storage Media Concepts
In large configurations, you can place secondary paging and swapping files on
other devices to balance disk load. See Section 16.16 for more information.
The OpenVMS Performance Management provides detailed information about
redistributing system files and achieving a balanced disk load.
9.1.4.2 Private Disk Volumes
A private volume is a file-structured volume that contains only private files.
Under some circumstances, users might want to perform their work on a device
that unauthorized users cannot access. By creating a private volume and
mounting it on a device allocated exclusively to a user’s process, you ensure
that users can perform their work without fear of interference from others.
Users can often prepare and manipulate their own private volumes. They might,
however, need your assistance if the computer and its peripheral devices are off
limits to or remotely located from them. Users requiring assistance can use the
operator communication manager (OPCOM) to communicate with an operator.
See Section 9.5.3 for instructions on answering users’ requests for assistance.
9.2 Allocating and Deallocating Drives
This section explains how to allocate and deallocate drives. The only situation in
which the ALLOCATE command is required, however, is when you must retain
control of the same volume across dismounts. An example of this is when you
alternate between mounting a tape using the /FOREIGN and /NOFOREIGN
qualifiers.
9.2.1 Allocating Drives
Use the DCL command ALLOCATE to logically assign a disk drive or a tape drive
to your process. You might do this if you suspect an error and want to reserve a
disk while you repair the error.
The ALLOCATE command allocates only one device to a process. To allocate
several devices, you must use multiple commands.
How to Perform This Task
Enter the ALLOCATE command using the following format:
ALLOCATE device-name[:] [logical-name]
where:
device-name Specifies the drive on which the volume will be loaded. The device
name can be a physical, generic, or logical name.
logical-name Specifies an optional logical name to be associated with the specified
disk or tape drive.
Examples
1.
$ ALLOCATE DUA2:
%DCL-I-ALLOC, _MARS$DUA2: allocated
In this example, the ALLOCATE command specifies a physical device named
DUA2:, which requests the allocation of a specific RK10 disk drive; that is,
unit 2 on controller A. The response from the ALLOCATE command indicates
that the device was successfully allocated.
Managing Storage Media 9–15