XENIX incremental dump tape format
commands are used to write
and read incremental dump magnetic tapes.
The backup tape consists of
a header record, some bit mask records,
a group of records describing file system directories,
a group of records describing file system files, and some
records describing a second bit mask.
The header record and the first record of each description
have the format described by the dumprestor structure
defined in the file /usr/include/dumprestor.h.
The members of the header structure are as follows:
The header type.
The date the backup was taken.
The date the file system was backed up.
The current volume number of the backup.
The current block number of this record. This
is counting 512-byte blocks.
The number of the inode being backed up if
of type TS_INODE.
This contains the value MAGIC, truncated as needed.
This contains whatever value is needed to
make the block sum to CHECKSUM.
This is a copy of the inode as it appears on the file system.
The following count of characters describes the file.
A character is zero if the block associated with that character was not
present on the file system; otherwise, the character is nonzero.
If the block was not present on the file system no block was backed up
and it is replaced as a hole in the file.
If there is not sufficient space in this block to describe
all of the blocks in a file, TS_ADDR
blocks will be scattered through the file, each one
picking up where the last left off.
This is the array of characters that is used as described above.
The TS_ entries are used in the
field to indicate the header type.
The types and their meanings are as follows:
Tape volume label.
A file or directory follows. The
field is a copy of the disk inode and contains
bits describing what sort of file this is.
A bit mask follows. This bit mask has one bit
for each inode that was backed up.
A subblock to a file (TS_INODE).
See the description of
End of tape record.
A bit mask follows. This bit mask contains one bit for
all inodes that were empty on the file system when backed up.
Other quantities defined in dumprestor.h are:
Header blocks checksum to this value.
All header blocks have this number in
The number of bits in a bit map word.
The number of bit map words.
The number of 512-byte blocks in a physical tape record.
Each volume except the last ends with a tapemark (read as an end
of file). The last volume ends with a TS_END
block and then the tapemark.
The structure idates
describes an entry of the file where backup history is kept.
header file defining the xbackup format
xbackup is not part of any currently supported
standard; it is an extension of AT&T System V provided
by The Santa Cruz Operation, Inc.
© 2003 Caldera International, Inc. All rights reserved.
SCO OpenServer Release 5.0.7 -- 11 February 2003