mtdump dumps the record structure of a tape image file in SIMH, E11, or
TPC format.  mtdump is invoked by

	mtdump {-sec} file1 file2 file3...

where -s specifies SIMH format, -e E11 format, and -c TPC format.  The
default is SIMH format.  Output is to stdout, unless redirected.

SIMH format is as follows:

	4 byte record length 1
	record 1
	repeat of 4 byte record length 1
	4 byte record length 2
	record 2
	repeat of 4 byte record length 2
	:
	4 bytes = 00000000 for end of file

and so on.  Records are padded to even byte length.

E11 format is similar to SIMH format, but odd length records are not padded
to even length.

TPC format is as follows:

	2 byte record length 1
	record 1
	2 byte record length 2
	record 2
	:
	2 bytes = 0000 for end of file

and so on.  Records are padded to even byte length.

mmdir is a variant of mtdump that dumps the directory structure of an
Interdata MMD (multimedia diagnostic) tape.  The tape must be in SMIH
format.