dump.8

UNIX v6源代码 这几乎是最经典的unix版本 unix操作系统设计和莱昂氏unix源代码分析都是用的该版

.th DUMP VIII 11/24/73
.sh NAME
dump \*- incremental file system dump
.sh SYNOPSIS
.bd dump
[ key [ arguments ] filesystem ]
.sh DESCRIPTION
.it Dump
makes an incremental file system dump
on magtape
of all files changed after a certain date.
The
.it key
argument
specifies the date and other options about the dump.
.it Key
consists of characters from
the set
.bd abcfiu0hds.
.s3
.lp +5 5
\fBa\fR	Normally files
larger than 1000 blocks are not incrementally dump;
this flag forces them to be dumped.
.s3
.lp +5 5
\fBb\fR	The next argument is taken to be the maximum size
of the dump tape in blocks (see \fBs\fR).
.s3
.lp +5 5
\fBc\fR	If the tape overflows, increment the last character
of its name and continue on that drive.
(Normally it asks you to change tapes.)
.s3
.lp +5 5
\fBf\fR	Place the dump on the next argument file
instead of the tape.
.s3
.lp +5 5
\fBi\fR	the
dump date is taken from the entry in the file
/etc/dtab
corresponding to the last time
this file system was dumped with
the
.bd -u
option.
.s3
.lp +5 5
\fBu\fR	the date just prior to this dump
is written on
/etc/dtab
upon successful completion of this dump.
This file contains a date for every
file system dumped with
this
option.
.s3
.lp +5 5
\fB0\fR	the dump date is taken as the epoch
(beginning of time).
Thus this option causes an entire file system dump to be taken.
.s3
.lp +5 5
\fBh\fR	the dump date is some number of hours before the current date.
The number of hours is taken from the next argument in
.it arguments.
.s3
.lp +5 5
\fBd\fR	the dump date is some number of days before the current date.
The number of days is taken from the next argument in
.it arguments.
.s3
.lp +5 5
\fBs\fR	the size of the dump tape is specified in feet.
The number of feet is taken from the next argument in
.it arguments.
It is assumed that there are 9 standard UNIX records per foot.
When the specified size is reached,
the dump will wait for reels to be changed.
The default size is 2200 feet.
.s3
.i0
.dt
.dt
If no arguments are given,
the
.it key
is assumed to be
.bd i
and the file system is
assumed to be
/dev/rp0.
.s3
Full dumps
should be taken on quiet file systems as follows:
.s3
	dump 0u /dev/rp0
.br
	ncheck /dev/rp0
.s3
The
.it ncheck
will come in handy in case it is necessary
to restore individual files from this dump.
Incremental dumps should then be taken
when desired by:
.s3
	dump
.s3
When the incremental dumps get cumbersome,
a new complete dump should be taken.
In this way,
a restore requires
loading of the complete dump tape and only the latest incremental tape.
.sh DIAGNOSTICS
If the dump requires more than one tape,
it will ask you to change tapes.
Reply with a new-line when this has been done.
If the first block on the new tape is not writable,
e.g. because you forgot the write ring,
you get a chance to fix it.
Generally, however, read or write failures are fatal.
.sh FILES
/dev/mt0	magtape
.br
/dev/rp0	default file system
.br
/etc/dtab
.sh "SEE ALSO"
restor (VIII), ncheck (VIII), dump (V)
.sh BUGS