User`s guide

BACKUP

and the /SAVESET option (the default). Unless you specify the /SUBSET option,

BACKUP presumes it is working with a saveset.

Each saveset is the result of a single backup operation, is stored in the format

of an RT–11 volume, and requires the BACKUP/DIRECTORY command to read

its contents.

Subset

A subset is a logical disk created by the BUP utility to hold one or more ﬁles

you speciﬁed with the BACKUP command and the /SUBSET option. Since more

than one ﬁle can be in a logical disk, it can be considered to contain a subset of

your ﬁles on a physical disk.

Subsets can be used like any other logical disks; however, unlike the logical disks

you create with the CREATE command, subsets have no free blocks in them.

out-spec

Speciﬁes the device in which you will mount the output volume(s) for the backup

operation and the saveset or logical-disk ﬁle name for the backup. The output

volume can be any type of media.

Out-Spec Defaults

• BACKUP—default output saveset or logical-disk name for a ﬁle backup.

• ddn (name of the device being backed up)—default output saveset name for

a device-image backup.

• BUP—default output saveset type for all saveset backups (ﬁle and device-

image)

• DSK—default output ﬁle type for all logical-disk subset backups.

• BUPDIR.DIR—default output ﬁle name and type for all BACKUP output ﬁles

containing directories of savesets.

• BACKUPDIR.DIR—default output ﬁle name and type for all BACKUP output

ﬁles containing directories of logical disks.

Input and Output Volumes

You can use random-access volumes and logical disks as either input or output

volumes for both backup and restore operations.

Magtapes, however, can be used only as output volumes for a backup operation,

and only as input volumes for a restore operation.

You can transport BUP-written magtapes to a VMS system and extract ﬁles from

those magtapes. After copying the savesets to a VMS directory, use the VMS

EXCHANGE utility to manipulate the ﬁles. The Introduction to RT–11 describes

this procedure.

8 RT–11 Command Descriptions