lp(7)                      DG/UX 4.30                       lp(7)



     NAME
          lp - DGC AViiON family line printer special files

     DESCRIPTION
          The character special device lp provides access to either
          Centronics-compatible parallel or standard parallel device
          interface to line printer devices.  The driver supports all
          current Data General printer models.

          The printer driver takes the characters written to it and
          sends them to the line printer hardware. If the printer
          hardware takes special action in response to particular
          characters output to the device, such as form feeds, the
          application may take advantage of these features by
          outputting the appropriate characters, but there are no
          dependencies on these features within the driver. The driver
          does not perform any special paper spacing or other forms
          control to handle paper folds, etc.

          The open system call performs appropriate device dependent
          checks to determine that the printer device is online and
          ready to print;  i.e., the printer must be ready to accept
          characters and print them without further operator
          intervention.  If the printer is not ready, the error ENXIO
          is returned.  A printer is an exclusive open device; the
          error ENXIO is returned if an attempt is made to open a
          printer that is already open.

          For the close system call, user visible functionality is the
          same as for an ordinary disk file.

          The read system call is not supported.  The error ENODEV is
          always returned.

          For the write system call, the contents of the caller's
          buffer are sent to the physical line printer.  If an error
          occurs on the I/O, the error EIO is returned.  If the
          printer is off-line when a write is started, or goes off-
          line while a write is in progress, the system call will pend
          until the printer is on-line and the data is written.

          The printer driver supports both the Centronics-compatible
          parallel and standard parallel interfaces.  The user
          configures the hardware through the System Control Monitor
          (SCM).  Refer to Using the AViiONTM System Control Monitor
          (SCM) for more information.

          Select always returns READY for both read and write
          operations.

     FILES
          /dev/lp*



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     lp(7)                      DG/UX 4.30                       lp(7)



     SEE ALSO
          lp(1).





















































     Licensed material--property of copyright holder(s)         Page 2