GNU/Linux man pages
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Unix |
Unix v7 |
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dump(5) |
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dump, ddate − incremental dump format
#include
<sys/types.h>
#include <sys/ino.h>
# include <dumprestor.h>
Tapes used by dump and restor(1) contain:
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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:
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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.
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TS_BITS |
A bit map follows. This bit map has a one bit for each inode that was dumped. | ||
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TS_ADDR |
A subrecord of a file description. See c_addr below. | ||
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TS_END |
End of tape record. | ||
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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. | ||
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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:
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c_type |
The type of the header. |
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c_date |
The date the dump was taken. |
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c_ddate |
The date the file system was dumped from. |
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c_volume |
The current volume number of the dump. |
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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.
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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.
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c_dinode |
This is a copy of the inode as it appears on the file system; see filsys(5). | ||
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c_count |
The count of characters in c_addr. | ||
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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:
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id_name |
The dumped filesystem is ’/dev/id_nam’. | ||
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id_incno |
The level number of the dump tape; see dump(1). | ||
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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)
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dump(5) | |