6.0;rwmt (read_write_magtape), revision 6.0, 83/03/01
RWMT (READ_WRITE_MAGTAPE) -- Read and write magnetic tapes for exchange
of information with non-DOMAIN installations.
Usage: RWMT {-R|-W|-I|-L} [pathname]... [option]... [-Prompt] {CL}
FORMAT
RWMT mode_control [pathname...] [options]
RWMT reads tapes from non-DOMAIN installations, and writes tapes which
can be read by non-DOMAIN installations. RWMT can read and write
unlabeled tapes, as well as ANSI level 1-4 labeled tapes.
For information on reading and writing tapes intended for exchange with
other DOMAIN installations, see HELP RBAK and HELP WBAK.
COMMAND LINE SUMMARY (Complete description follows.)
-R causes one or more tape files to be read & stored on disk
-W causes one or more disk files to be written to tape
-I causes an ANSI-labeled physical tape volume to be indexed
-L causes ANSI volume labels to be written on a physical tape
volume
-ANSI specifies that the tape is labeled in conformance to ANSI
X3.27-1978, level 1, 2, 3, or 4 (default)
-UNLAB specifies that the tape is unlabeled
-ASC specifies that all tape file contents are in ASCII (default)
-EBC specifies that all tape file contents (not labels) are in
EBCDIC
-RAW specifies that all tape file data is to be treated in raw form
-VID volid specifies a 1-6 character volume ID. Use when labeling volume
(-L argument) (default = ' ')
-OWN ownerid specifies a 1-14 character owner ID. Use when labeling volume
(-L argument) (default = ' ')
-FID fileid specifies a 1-17 character file ID to be written in the file
header label. Use when writing a file to a labeled volume
(-W argument) (default is 1st 17 characters of right-most
pathname component)
-F fileno|CUR|END
specifies a tape file sequence number. Use when reading or
writing a file (-R or -W argument); if multiple pathnames are
supplied, this value is incremented by one after each file
has been read or written. If "CUR" is supplied in lieu of
an ordinal file number, the file at the current tape position
is used; the tape must have previously been read or written
by RWMT and its position must not have been disturbed.
"END" causes the backup file to be written at the very end
of the file set.
(default = 1)
-RL reclen specifies the length, in bytes, of a record in the tape file.
(default = 80)
-BL blocklen specifies the length, in bytes, of a physical tape block.
(default = 80)
-BF blockfac specifies a blocking factor; this is an alternative to the
-BL option.
-RF format specifies record format - 'F' for fixed length records and
blocks, 'D' for variable length records, 'S' for spanned
records, or 'U' for undefined record format (default = 'F')
-PAR causes parity bits to be forced off when reading data from
tape and forced on when writing data to tape
-NPAR causes no disturbance of parity bits when reading or writing
data (default)
-DEV M<unit> specifies the magtape unit number (default = 0)
-SBIN causes all stream files written to contain the "binary"
attribute (normally, output stream files contain the
"ascii" attribute)
-P causes RWMT to query for all unspecified options.
FULL DESCRIPTIONS
ARGUMENTS
pathname
(optional) Specify name of file to be read from or written to tape.
This argument is only valid with the -R and -W mode_control
options (below). Multiple pathnames and wildcarding are
permitted.
Default if omitted: read pathnames from standard input
OPTIONS
(Default options are indicated by "(D)".)
= Mode control =
One of the following mode_control options must be specified. If you omit
it, RWMT will prompt you for it. You may have RWMT prompt for all
necessary options by using the -P option.
-L[ABEL] Write ANSI X3.27-1978 volume label on a tape. This
option causes RWMT to write an ANSI volume label and
dummy file on the magtape volume. An optional owner
and volume ID, which are stored in the volume label,
may be specified (see -VID and -OWN below). This is
the way to initialize a labeled tape; if any informa-
tion existed on the tape, it is erased by this labeling
operation.
If you are labeling a tape, then the following two
options may also be used.
-VID vol_id Specify a 1-6 character volume ID for
use when labeling a volume. This option
is only valid when used with the -L
mode_control option (above). The default
volume ID is ' ' (blank).
-OWN owner_id Specify a 1-14 character owner ID for
use when labeling a volume. This option
is only valid when used with the -L
mode_control option (above). The default
owner ID is ' ' (blank).
-I[NDEX] List objects on an ANSI-labeled physical tape volume.
-INDEX produces a listing of all files or file sections
on an ANSI-labeled physical tape volume. The contents
of the physical volume (VOL1) label and all file header
labels are written to standard output.
-W[RITE] Specify one or more disk files ('pathname' argument) to
be written to tape. The default format is ANSI labeled,
ASCII, fixed-length records of 80 bytes each, and 80-byte
blocks. If desired, any of these parameters can be changed
using the options described below. If more than one pathname
is specified, the disk files are written to sequential tape
files. Tapes written by RWMT are always in accordance with
ANSI level 4 format.
Before writing a labeled file, the tape volume itself must
be labeled with the -LABEL mode_control option (above).
-R[EAD] Specify one or more tape files to be read from tape and
stored on disk. READ reads one or more tape files and
writes them to disk using the specified pathnames
('pathname' argument). The default tape file format
is the same as that for the WRITE option. If the tape
is labeled under ANSI level 2, 3 or 4, the file format
(block length, record length, and record format) is read
from the tape. If the tape is unlabeled, or labeled with
ANSI level 1, you must specify the tape format using the
options below. If more than one pathname is specified,
adjacent tape files are read and stored under the
specified pathnames.
= Label Control =
-ANSI (D) Specify that the tape is labeled in conformance to ANSI
X3.27-1978, level 1, 2, 3, or 4.
-UNLAB Specify that the tape is unlabeled.
= Tape Format =
-ASC (D) Specify that all tape file contents are in ASCII characters.
-EBC Specify that all tape file contents (except labels) are in
EBCDIC characters.
-RAW Specify that all tape file data is to be treated in raw form
(see example 5).
-NPAR (D) Specify no disturbance of parity bits when reading or
writing data.
-PAR Specify that parity bits should be forced off when reading
data from tape and forced on when writing data to tape.
-RL reclen Specify the maximum length, in bytes, of a record in the
tape file. This option is only valid when used with either
the -R or -W mode_control options (above). It is unnecesary
when reading an ANSI level 2, 3, or 4 file. The default
record length is 80 bytes.
-BL blocklen Specify the length, in bytes, of a physical tape block.
This option is only valid when used with either the -R or
-W mode_control options (above). It is unnecesary when
reading an ANSI level 2, 3, or 4 file. The default block
length is 80 bytes.
-BF blockfac Specify a blocking factor -- the number of records to
store into or read from a physical tape block. This is
an alternative to the -BL option, since the record length
multiplied by the blocking factor yields the block length.
This option is only valid when used with either the -R or
-W mode_control options (above). Using this option is
only meaningful if your tape has fixed length records.
This option is unnecesary when reading an ANSI level 2, 3,
or 4 file. The default blocking factor is 1.
-RF format Specify record format. Valid values for 'format' are
"F" (fixed length records and blocks); "D" (variable
length records (this is ANSI 'D' format)); "S" (spanned
records); or "U" (undefined record format). The default
format is "F".
= Tape File Identifiers =
-FID file_id Specify a 1-17 character file ID to be written in the
file header label for use when writing a file to a
labeled volume. This option is only valid when used
with the -W mode_control option (above). If this option
is omitted, the name of the file being written is used.
-F [position] Specify the file position for -R or -W operations. Valid
values for 'position' are "CUR", "END", or a non-zero
integer value. A position of "CUR" selects the current
tape position; the tape must have been previously read
or written by RWMT and its position must not have been
disturbed. This option is only valid when used with
either the -R or -W mode_control options (above).
A position of "END" selects the end of the tape file set.
This option is valid only when used with the -W
mode_control option, and causes RWMT to append the
specified disk file ('pathname' argument) to the very
end of the tape file set.
A position specified by a non-zero integer value selects
the file at that absolute position in the tape volume.
This option is only valid when used with either the -R or
-W mode_control options (above). If multiple 'pathname'
arguments are supplied, the value of 'position' is
incremented by one after each file has been read or written.
The default value for 'position' is 1.
= Tape Control =
-DEV Munit Specify the magtape unit number. 'unit' is an integer
(0-3) and is required (i.e., -DEV M2). If this option
is omitted, RWMT assumes device M0.
= Misc. Control Options =
-SBIN Cause all stream files written to contain the "binary"
attribute (normally, output stream files contain the
"ascii" attribute).
-P Cause RWMT to prompt for all unspecified parameters.
RWMT uses the command line parser, and so also accepts the standard command
options listed in HELP CL.
EXAMPLES
1. $ rwmt -label -own "R and D" -vid "demo" Initialize a tape with
the given owner and
volume ID.
2. $ rwmt -w c?*_example -f 1 -rf d -rl 200 -bl 2048 Copy the
32 records of "cmf_example" written to tape file @ 1. wildcarded
8 records of "cmt_example" written to tape file @ 2. files to
4 records of "cpboot_example" written to tape file @ 3. tape.
25 records of "cpf_example" written to tape file @ 4.
3. $ rwmt -index List the files on the tape.
Volume label:
Volume ID: "DEMO " Owner ID: "R AND D " Access: " "
File/Section File ID Cr Date Acc RF RL BL
1 1 CMF_EXAMPLE 83/02/17 D 200 2048
2 1 CMT_EXAMPLE 83/02/17 D 200 2048
3 1 CPBOOT_EXAMPLE 83/02/17 D 200 2048
4 1 CPF_EXAMPLE 83/02/17 D 200 2048
5 1 CPT_EXAMPLE 83/02/17 D 200 2048
End of file set.
$
4. $ rwmt -r cpboot_example.tape -f 3 Copy tape file 3 to a
4 records read from tape file 3 into disk file named
"cpboot_example.tape". "cpboot_example.tape".
$
5. RAW mode
RWMT permits a tape file to be read in RAW mode. In this mode, each
block read from the tape is written into one record in a stream file,
unmodified by the program. To read a file in RAW mode, you should
specify the maximum record size using the -RL argument. If you do not,
the default value of 80 bytes is used, and any records longer than that
are truncated. Also, undefined record format should be used.
For example:
$ rwmt -r -f 1 -rf u -raw -rl 512 rawfile
reads tape file number 1 into "rawfile", with a maximum record length
of 512 bytes.
Files may be written in the same manner:
$ rwmt -w -f 1 -rf u -raw -rl 512 rawfile
RELATED TOPICS
More information is available. Type:
- HELP RBAK and HELP WBAK
for details on reading and writing tapes for use only at DOMAIN sites.
- HELP MAGTAPE
for general information on magnetic tape usage and support.