MEDIA Aegis MEDIA
NAME
media - removable media information
DESCRIPTION
CARTRIDGE -- Cartridge Tape Usage Information
---------------------------------------------
A Domain network may read and write data residing on cartridge tapes
on a DN550. Cartridges may be either ansi labeled or unlabeled, with
files of ascii, ebcdic, or raw characters. Cartridge tape supports
only 512 byte blocks (although smaller may be specified) and fixed
length record format only. System bootable cartridge tapes are also
supported.
The following general restrictions apply:
o You must perform the tape operations on the node to which the
cartridge drive is attached.
o Only one drive may be attached to any particular node.
The following commands are supplied for use with cartridge tapes:
o wbak (write_backup) writes one or more object trees to a
cartridge for backup, or to interchange files with other Domain
installations. Certain wbak options are valid only for cartridge
tapes (-reten, -no_eot, -sysboot).
o rbak (read_backup) indexes or restores to disk the contents of a
backup file written with the wbak command.
o rwmt (read_write_magtape) transfers files between disk and
cartridge. Use this command to interchange files with other,
non-Domain installations.
o edmtdesc (edit_magtape_descriptor_file) creates and modifies
cartridge descriptor files for use with streams.
Help is available for all of these commands. Type 'help' followed by
the relevant command name for more information.
magtape -- Magnetic Tape Usage Information
------------------------------------------
A Domain network may read and write data residing on 9-track magnetic
tapes formatted to a density of 1600 bits per inch. Tapes may be either
ansi labeled or unlabeled, with files of ascii, ebcdic, or raw
characters. The following general restrictions apply:
- You must perform the tape operations on the node to which the tape
drive is attached.
- Only one tape drive may be attached to any particular node.
@end(itemize)
The following commands are supplied for use with magnetic tapes:
- wbak (write_backup) writes one or more object trees to a magtape for
backup, or to interchange files with other Domain installations.
- rbak (read_backup) indexes or restores to disk the contents of a
backup file written with the wbak command.
- rwmt (read_write_magtape) transfers files between disk and magtape.
Use this command to interchange files with other, non-Domain
installations.
- edmtdesc (edit_magtape_descriptor_file) creates and modifies magtape
descriptor files.
Help is available for all of these commands. Type 'help' followed by the
relevant command name for more information.
volid -- Automatic volume id generation for labeled tapes
---------------------------------------------------------
The rwmt (read_write_magtape) and wbak (write_backup) commands provide
three ways to generate the volume id for labeled tapes:
1. The id may be supplied explicitly with the -vid option.
2. It may be generated automatically, as described below.
3. If no id is supplied, and if automatic volume id generation has not
been enabled, then the default volume id of spaces is used.
To enable automatic volume id generation, make sure the directory
`node_data/system_logs exists. In `node_data/system_logs, use the DM
editing capabilities to create a file called next_volume_id. Place a 1-6
character alphanumeric text string in this file. This is the string
which will be used as the volume id the next time a tape is to be
labeled. When a labeling operation occurs, the string is automatically
updated by adding 1 to the right-most non-space character of the string,
and carrying to the left if the character was "9" or "Z".
At software release 9.7 the above method of automatic labeling is
suggested. However, for backwards compatiblity if
`node_data/system_logs/next_volume_id is not found the volume id will be
taken from /sys/tape/next_volume_id if it exists.