DUMP(5) File Formats Manual DUMP(5)
dump, ddate - incremental dump format
Tapes used by dump and restor(8) 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:
#if UCB_NKB == 1
#define NTREC 10
#define NTREC 20
#define MLEN 16
#define MSIZ 4096
#define TS_TAPE 1
#define TS_INODE 2
#define TS_BITS 3
#define TS_ADDR 4
#define TS_END 5
#define TS_CLRI 6
#define MAGIC (int)60011
#define CHECKSUM (int)84446
NTREC is the number of BSIZE (sys/param.h) 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
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.
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.
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.
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 tape-
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 file system is `/dev/id_nam'.
id_incno The level number of the dump tape; see dump(8).
id_ddate The date of the incremental dump in system format see types(5).
filsys(5), types(5), dump(8), dumpdir(8), restor(8)
3rd Berkeley Distribution DUMP(5)