dump.5

<B>Digital的Unix操作系统VAX 4.2源码</B>

.\" SCCSID: @(#)dump.5	8.1	9/11/90
.TH dump 5 
.SH Name
dumprestor, dumpdates \- incremental dump format
.SH Syntax
.B #include <sys/types.h>
.br
.B #include <sys/inode.h>
.br
.B #include <dumprestor.h>
.SH Description
.NXR "dump keyword"
.NXAM "dump command" "dump file"
.NXB "dumprestor file" "format"
Tapes used by
.PN dump
and 
.PN restore
contain:
.nf
A header record
Two groups of bit map records
A group of records describing directories
A group of records describing files
.fi
.PP
The format of the header record and of the first
record of each description as given in the
include file <dumprestor.h>
is:
.NXR "dumprestor file" "format"
.EX 0
#define NTREC   	10
#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

struct	spcl {
	int		c_type;
	time_t		c_date;
	time_t		c_ddate;
	int		c_volume;
	daddr_t		c_tapea;
	ino_t		c_inumber;
	int		c_magic;
	int		c_checksum;
	struct		dinode		c_dinode;
	int		c_count;
	char		c_addr[BSIZE];
} spcl;

struct	idates {
	char		id_name[16];
	char		id_incno;
	time_t		id_ddate;
};

#define	DUMPOUTFMT	"%-16s %c %s"		/* for printf */
						/* name, incno, ctime(date) */
#define	DUMPINFMT	"%16s %c %[^\en]\en"	/* inverse for scanf */
.EE
.PP
NTREC is the number of 1024-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.
.PP
The
TS_ entries are used in the
.I c_type
field to indicate what sort of header
this is.
The types and their meanings are as follows:
.NXR "dump file" "TS_entry list"
.TP 13
TS_TAPE
Tape volume label.
.PD 0
.TP
TS_INODE
A file or directory follows.
The
.I c_dinode
field is a copy of the disk inode and contains
bits telling what sort of file this is.
.TP
TS_BITS
A bit map follows.
This bit map has a one (1) bit
for each inode that was dumped.
.TP
TS_ADDR
A subrecord of a file description.
See
.I c_addr
described in the next list.
.TP
TS_END
End of tape record.
.TP
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.
.TP
MAGIC
All header records have this number in
.I c_magic.
.TP
CHECKSUM
Header records checksum to this value.
.PD
.PP
The fields of the header structure are as follows:
.NXR "dump file" "field reference list"
.TP 13
c_type
The type of the header.
.PD 0
.TP
c_date
The date the dump was taken.
.TP
c_ddate
The date the file system was dumped from.
.TP
c_volume
The current volume number of the dump.
.TP
c_tapea
The current number of this (1024-byte) record.
.TP
c_inumber
The number of the inode being dumped if this
is of type TS_INODE.
.TP
c_magic
This contains the value MAGIC
above, truncated as needed.
.TP
c_checksum
This contains whatever value is needed to
make the record sum to CHECKSUM.
.TP
c_dinode
This is a copy of the inode as it appears on the
file system.  For further information, see 
.MS fs 5 .
.TP
c_count
The count of characters in
.I c_addr.
.TP
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 nonzero.
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.
.PD
.PP
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.
.PP
The structure
.I idates
describes an entry in the file
.PN /etc/dumpdates
where dump history is kept.
The fields of the structure are:
.NXR "dumpdates file" "field reference list"
.TP \w'TS_INODE\ 'u
id_name
The dumped filesystem is
.RI `/dev/ id_nam'.
.PD 0
.TP
id_incno
The level number of the dump tape.  For further information,
see 
.MS dump 8 .
.TP
id_ddate
The date of the incremental dump in system format.  
For further information, see 
.MS types 5 .
.PD
.SH Files
.PN /etc/dumpdates
.SH See Also
fs(5), types(5), dump(8), restore(8)
.NXE "dumprestor file" "format"