mtdump dumps the record structure of a tape image file in SIMH, E11, TPC, or P7B format. mtdump is invoked by mtdump {-secp} file1 file2 file3... where -s specifies SIMH format, -e E11 format, -c TPC format, and -p P7B 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. P7B format is confined to 7 track tapes, as follows: start of record + first 6b character and parity : last character start of record + first 6b character and parity and so on. A P7B tape must have a dummy "last record" with a start of record indicator. A tape mark is indicated by a character of 317 (start of record, character 17, wrong parity for odd parity, reserved character for even parity). 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.