dump, ddate - incremental dump format

#include <sys/types.h>
#include <sys/ino.h>
#include <dumprestor.h>

Tapes used by dump and restor (1) contain:

a header record

two groups of bit map records

a group of records describing directories

a group of records describing files

The format of the header record and of the first record of each description as given in the include file <dumprestor.h> is:

NTREC is the number of 512 byte records in a physical tape block. MLEN is the number of bits in a bit map word. MSIZ is the number of bit map words.

The TS_ entries are used in the c_type field to indicate what sort of header this is. The types and their meanings are as follows:

TS_TAPE	Tape volume label
TS_INODE	A file or directory follows. The c_dinode field is a copy of the disk inode and contains bits telling what sort of file this is.
TS_BITS	A bit map follows. This bit map has a one bit for each inode that was dumped.
TS_ADDR	A subrecord of a file description. See c_addr below.
TS_END	End of tape record.
TS_CLRI	A bit map follows. This bit map contains a zero bit for all inodes that were empty on the file system when dumped.
MAGIC	All header records have this number in c_magic.
CHECKSUM	Header records checksum to this value.

The fields of the header structure are as follows:

c_type	The type of the header.
c_date	The date the dump was taken.
c_ddate	The date the file system was dumped from.
c_volume	The current volume number of the dump.
c_tapea	The current number of this (512-byte) record.
c_inumber	The number of the inode being dumped if this is of type TS_INODE.
c_magic	This contains the value MAGIC above, truncated as needed.
c_checksum	This contains whatever value is needed to make the record sum to CHECKSUM.
c_dinode	This is a copy of the inode as it appears on the file system; see filsys (5).
c_count	The count of characters in c_addr.
c_addr	An array of characters describing the blocks of the dumped file. A character is zero if the block associated with that character was not present on the file system, otherwise the character is non-zero. If the block was not present on the file system, no block was dumped; the block will be restored as a hole in the file. If there is not sufficient space in this record to describe all of the blocks in a file, TS_ADDR records will be scattered through the file, each one picking up where the last left off.

Each volume except the last ends with a tapemark (read as an end of file). The last volume ends with a TS_END record and then the tapemark.

The structure idates describes an entry of the file /etc/ddate where dump history is kept. The fields of the structure are:

id_name	The dumped filesystem is `/dev/ id_nam'.
id_incno	The level number of the dump tape; see dump (1).
id_ddate	The date of the incremental dump in system format see types (5).

/etc/ddate

dump(1), dumpdir(1), restor(1), filsys(5), types(5)