tc(7)                               CLIX                               tc(7)



  NAME

    tc - Tape controller driver

  DESCRIPTION

    The tc driver is the Small Computer System Interface (SCSI) tape
    controller driver.  It supports half-inch reel, quarter-inch cartridge,
    and 8 mm helical scan tape drives connected to I/O processor (IOP) and
    quad-SCSI (QS) boards.

    The half-inch reel tape drive and 8mm helical scan tape drives support
    variable record sizes at variable densities.  The quarter-inch cartridge
    tape drive supports only a fixed-block size of 512 bytes at fixed
    densities determined by QIC standards.

    The /dev/rmt/mt5n file is a typical special file to access a tape, where
    the SCSI controller address is 5 and the device is not rewound upon
    completion of the close() function.  The format of the minor device mask
    for tc is shown below:

                 _______________________________________________
                |  7 |   6 |   5 |   4 |   3 |   2 |   1 |   0 |
                |__________|___________|_________________|_____|
                |          |           |                 |     |
                | IOP/CHAN |    TYPE   |      SCSI ID    |  REW|
                |__________|___________|_________________|_____|

    TYPE defines a specific SCSI bus, as shown in the following chart.  If
    TYPE is I/O processor, the IOP defines the I/O processor number.  If TYPE
    is quad-SCSI, CHAN defines the bus, or channel number.

                       ___________________________________
                      | TYPE (binary)|  System Controller|
                      |______________|___________________|
                      | 0  0         |  I/O processor    |
                      |______________|___________________|
                      | 0  1         |  Quad-SCSI board 0|
                      |______________|___________________|
                      | 1  0         |  Quad-SCSI board 1|
                      |______________|___________________|
                      | 1  1         |  Reserved         |
                      |______________|___________________|

    The tc devices operate as described in mtio(7).  Exceptions exist for
    quarter-inch cartridge tape, due to limitations with that type of device.

  FILES

    /dev/rmt/mt?[n]   Special file for accessing tape driver.




  2/94 - Intergraph Corporation                                              1

  tc(7)                               CLIX                               tc(7)



  NOTES

    The largest possible transfer is 64K bytes if the buffer address is 1K
    byte aligned.  Otherwise, the largest transfer is 62K bytes.

  CAUTIONS

    The quarter-inch cartridge tape supports write() function operations after
    an initial tape load, rewind, forward-skip-to-EOT, write-file-mark, or a
    preceding write.

    Since the quarter-inch cartridge tape supports fixed-block mode only,
    transfer counts must be multiples of 512 bytes and record sizes are not
    preserved.  In addition, a partial write may occur just before the
    indication of end-of-tape (EOT).  An EOT on write is indicated by a return
    value of 0.

  RELATED INFORMATION

    Commands:  mt(1)

    Functions:  ioctl(2)

    Files:  mtio(7)






























  2                                              Intergraph Corporation - 2/94