Duptape / recordio

Duptape(1) is an easy-to-use script for duplicating tapes, preserving
record boundaries and filemarks.  It will copy locally or to/from a
tape drive on a remote host.

Duptape uses recordio(1), a program that will either:
    (a) read files from a tape and write them as a single stream to stdout,
	adding enough information that the original tape with its original
	record sizes and filemarks can be reconstructed;
or:
    (b) read a stream as described in (a), reconstruct the original data,
	and write to tape.

The output from recordio's tape-reading mode can be put on a disk file,
if desired, and later fed to recordio's tape-writing mode.

By default a tape is copied through double-EOF, but this can be changed
with the -n option.

duptape is a script that wraps the calls to recordio in an easy-to-use
rcp-style interface.

---------------------

After writing duptape, I learned about the existence of "copytape",
by David Hayes.  Copytape and recordio have much the same functionality;
had I known about copytape, I wouldn't have written recordio.

The "duptape" script, with its nice rcp-like interface, doesn't have
a counterpart in copytape, but "copytape" fans would find it easy to
adapt duptape to call copytape instead of recordio.

---------------------

Duptape use:

    % duptape [options] [[username@]host1:]fromtape [[username@]host2:]totape

Examples:

    # Local tape to local tape:
    #
    % duptape /dev/nrst0  /dev/nrst1

    # Local tape to remote tape, using a 64 KB copy buffer:
    #
    % duptape -b 64k /dev/nrst0  joe@otherhost:/dev/rmt/2mn

Main duptape options:
	-b bs	copy buffer size.  Default 32 KB.
	-n nf	number of filemarks to copy thru.  Default through double EOF.
		Note that end of data on an Exabyte tape acts like double EOF.

Restrictions:
	ssh(1) is used to execute commands on a remote host.
	Thus you must have rlogin permission on fromhost and tohost.
	You can override the use of ssh with the environment variable
	DUPTAPE_RSH, which specifies a path to an rsh-like command.

	The program "recordio" must exist on the host(s).

---------------------

    # Typical recordio use:
    #
    % recordio -r < fromtape | ... | recordio -w > totape

    # Local tape to disk file, then disk file to tape:
    #
    % recordio -r < tapedev > diskfile
    % recordio -w < diskfile > tapedev