Magnetic Tape ioctl's are just (again) a compatibility problem with Linux. The /etc/rmt protocol allows to send ioctls to the remote system and relies on the fact that MTIO opcodes 0..7 of all UNIX systems are mapped to the same function. Linux unfortunately does not follow these rules. /*--------------------------------------------------------------------------*/ All other UNIX /*--------------------------------------------------------------------------*/ /* * values for mt_op */ #define MTWEOF 0 /* write an end-of-file record */ #define MTFSF 1 /* forward space over file mark */ #define MTBSF 2 /* backward space over file mark (1/2" only ) */ #define MTFSR 3 /* forward space to inter-record gap */ #define MTBSR 4 /* backward space to inter-record gap */ #define MTREW 5 /* rewind */ #define MTOFFL 6 /* rewind and put the drive offline */ #define MTNOP 7 /* no operation, sets status only */ /*--------------------------------------------------------------------------*/ Linux /*--------------------------------------------------------------------------*/ /* Magnetic Tape operations [Not all operations supported by all drivers]: */ #define MTRESET 0 /* +reset drive in case of problems */ #define MTFSF 1 /* forward space over FileMark, * position at first record of next file */ #define MTBSF 2 /* backward space FileMark (position before FM) */ #define MTFSR 3 /* forward space record */ #define MTBSR 4 /* backward space record */ #define MTWEOF 5 /* write an end-of-file record (mark) */ #define MTREW 6 /* rewind */ #define MTOFFL 7 /* rewind and put the drive offline (eject?) */ #define MTNOP 8 /* no op, set status only (read with MTIOCGET) */ Operation Description UNIX -> Linux ==================================================================== 0 weof writes EOF (file mark) resets drive!!! 1 fsf forward skip file mark OK 2 bsf backwd skip file mark OK 3 fsr forward skip record OK 4 bsr backwd skip record OK 5 rew rewind writes file mark!!! 6 offl unload media partially OK 7 nop set status in driver unloads media 8 NOP is mapped to the vendor dependant range. On Sun this is a retension which takes a long time... The rmt server and client code used in the star distribution voids these problems with Linux.