intro(7)                                                              intro(7)


NAME
     intro - introduction to special files

DESCRIPTION
     This section describes various special files that refer to specific
     hardware peripherals, and IRIX system device drivers.  STREAMS (see
     ioctl(2) system calls are also described.

     For hardware-related files, the names of the entries are generally
     derived from names for the hardware, as opposed to the names of the
     special files themselves.  Characteristics of both the hardware device
     and the corresponding IRIX system device driver are discussed where
     applicable.

     Disk device filenames are described in dks(7M).

     Tape device filenames are in the following format:

          /dev/rmt/typecontrollerdunit{nr}{ns|s}{v}{stat}{.density}{c}

     Where:

     type         Identifies the controller type.

     controller   Indicates the controller number.

     unit         Indicates the device attached to the controller.

     nr           Indicates a non rewinding interface.

     ns           Indicates bytes are not swapped.  This should be used for
                  all tape types other than QIC, in almost all cases.  It
                  should also be used for QIC tapes imported from or exported
                  to systems other than IRIX.

     s            Indicates bytes are swapped by the driver, primarily for
                  backwards compatibility with older Silicon Graphics systems.

     v            Indicates that the variable blocksize device should be used.
                  This device writes a single logical block per read or write
                  system call.  The fixed block device transfers 1 or more
                  logical blocks per read or write system call.  Variable mode
                  is preferred on 9-track, DAT, and often when importing or
                  exporting 8mm media from non-IRIX systems.

     stat         A special device that can be used only for the MTIOCGET
                  ioctl.  All other I/O requests and ioctls fail with the
                  EINVAL errno.


     .density     Optionally specifies the media density, where appropriate.
                  For devices with only one density setting, density is
                  omitted.  The . is used to keep the unit from visually
                  merging with the density.

     c            indicates a device which performs hardware data compression
                  and should not be confused with density.

     The /dev/mt directory exists as a link to /dev/rmt as a portability aid;
     IRIX does not support block mode tape access.  Not all tape types support
     all of these options.  For backwards compatibility, a tape device with
     neither ns, nor s is created.  It is normally the same device as the s
     device for QIC tapes and ns for all other tape types.

SEE ALSO
     MAKEDEV(1M), fx(1M), hinv(1M), mt(1), prtvtoc(1M).

NOTE
     The other devices in section 7 can be listed with:

          man -w 7 '*'

     or all of them can be read with:

          man 7 '*'


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