pmttapetab(4M) TCP/IP R4.11 pmttapetab(4M)
NAME
pmttapetab - table of remote tape devices
DESCRIPTION
The file /etc/pmttapetab contains an ASCII table describing magnetic
tape devices on remote hosts. It associates local pseudo tape
devices with these remote tape devices. The system administrator can
modify its contents with a text editor. It is read by the pmtd(1M)
daemon, which performs remote tape access across a network.
The file consists of a number of lines of the following format:
pseudo host os real rmtdir block cache
where:
pseudo is the local pseudo tape device. It should be the name of
the particular special file created at boottime in the
/dev/pmt directory. This is a filename.
host is the name of the remote host. This machine MUST have the
name of the client machine (the one running pmtd(1M)) in its
/etc/hosts.equiv file.
os is the name of the operating system running on host. This
should be one of the operating system names specified in
/etc/pmterrtab.
real is the real name for the tape device on host. The name must
be the full pathname of a character special device on host.
rmtdir is the name of the directory on host that contains the
rmt(1) daemon executable. This is a full pathname.
block is a modulo block size that the remote hardware requires.
The size of data transfers must be an integer multiple of
this value. Enter a block size of 0 in these 2 cases:
* The remote drive supports variable-length records and you
do not care what the block size is.
* The remote drive supports variable-length records and
data transfers are being cached (see below).
The QIC 150MB 1/4" cartridge drive (model 6577) supports only
512 byte fixed-length records. All other Data General tape
drives support variable-length records.
cache is a flag specifying that data transfers should be cached.
Specify Y to cache and N not to cache. Do not specify cache
in these 2 cases:
* The data transfer may require more than one tape.
* You specified a block size (see above) other than 0 for a
remote drive that supports variable-length records.
Use spaces or tabs to separate fields. Lines beginning with a # are
ignored. They may be used to add comments. If you need to use
spaces or tabs in the real field, surround the contents of the field
with double quotes.
It is the responsibility of the system administrator to maintain this
file and keep it up to date.
EXAMPLE
For example, assume /etc/pmttapetab contains the following entry:
0n atlanta dg /dev/rmt/0n /etc 512 N
In this case, entering the following command line would access the no
rewind rmt 0 device on the host atlanta:
tar -xvf /dev/pmt/0n
sysadm considers pmt devices to be valid input mediums.
FILES
/etc/pmttapetab Table with information about remote tape devices.
/etc/pmterrtab Table of equivalent error numbers.
/etc/hosts.equiv List of trusted host machines.
SEE ALSO
pmtd(1M), rmt(1M), hosts.equiv(4M), pmterrtab(4M), pmt(7), rmt(7).
CAVEATS
The real device name on the remote host must be a character special
device. Typically these are kept in the host's /dev/rmt directory.
Programs that read /etc/pmttapetab will assume the real tape devices
listed are character special.
No-rewind-on-close pseudo entries should only be paired with no-
rewind-on-close real entries in the /etc/pmttapetab file. The same
follows for rewind-on-close entries.
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