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QT(7)               RISC/os Reference Manual                QT(7)



NAME
     qt - SCSI QIC-100 tape interface

SYNOPSIS
     VECTOR: module=sha vector=0x8 ipl=2 unit=1 base=010

DESCRIPTION
     The QIC-100 SCSI tape is a 3-1/2 inch random access tape
     used for backups, software distribution, and file transfer.

     In raw I/O, buffers should be page aligned for best perfor-
     mance and I/O counts should be a multiple of 16384 bytes (a
     pair of overlapped tape blocks).  Likewise seek calls should
     specify a multiple of 16384 bytes.

     ISI QIC-100 tapes contain a 16 kilobyte directory in the
     first two blocks which allows multiple files on tape.  The
     files can contain blocks of variable length, but any partic-
     ular file must contain only one block length (except for the
     last block which may be shorter or longer).  Ioctl calls to
     space forward (reverse) files or records use the directory
     information to go directly to the correct block on the ran-
     dom access tape.

     Since the tape format works with 8k blocks (16k pairs of
     overlapped blocks in the case of 1:1 interleave), accesses
     which are not in multiples of 16k are buffered by the
     driver.  In any event, the directory is not updated until
     the device is closed.  Therefore, tapes should never be
     removed from the drive while the device is open.

FILES
     /dev/mt/ctape0 block rewind device
     /dev/mt/ctape4 block non-rewind device
     /dev/rmt/m0    raw rewind device
     /dev/rmt/m4    raw non-rewind device

SEE ALSO
     mt(1)

DIAGNOSTICS
     The following diagnostics are printed by the qt driver:

     qt%d mode sense failed
                         Although the tape drive was present, the
                         driver was unsuccessful in requesting
                         drive specific information.

     qt%d: no cartridge or tape not formatted
                         The driver was unable to read the first
                         block from the tape, either because no
                         cartridge was inserted, the tape was



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QT(7)               RISC/os Reference Manual                QT(7)



                         unformatted, or the drive was defective.

     qt%d: new tape: creating directory
                         The first block of the tape did not con-
                         tain a valid directory.  The driver
                         creates a new empty directory. This
                         directory is not written to the tape
                         unless a write call is executed.

     qt%d: tape is write protected
                         Self explanatory.

     qt%d: record size changed twice
                         The qictp driver handles fixed blocksize
                         files, with the exception that the last
                         block in a file may be a different size.
                         All attempts to write to a tape file
                         after a short (or long) block is written
                         will be rejected with this message.

     qt%d: reassigning block %d (0x%x)...done

     qt%d: reassigning block %d (0x%x)...failed
                         If the reassigning device is used
                         (GT_NO_REASSIGN not set) and an unrecov-
                         erable medium write error occurs, the
                         driver will attempt to reassign the
                         failing logical block and retry the
                         write.  Reassignment may fail if the
                         alternate block is already in use.

     qt%d: tape changed or drive reset
                         The drive asserted unit attention, indi-
                         cating a reset, power up, or changed
                         tape cartridge.  To prevent destruction
                         of data, no more accesses are permitted
                         until the device is closed and reopened.

     qt%d: tape blocksize wrong
                         Attached drive is apparently wrong type,
                         and will not work with driver.

     qt%d: %s: code %x : reissued
                         Various SCSI drive errors: see disk
                         drive manual or call Technical Support
                         for detailed explanation.  When an error
                         has occurred the driver will retry the
                         command up to 3 times.

SEE ALSO
     tpd(5spp)




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