lp(7)                            DG/UX R4.11                           lp(7)


NAME
       lp - Parallel line printer controller (88k only)

SYNOPSIS
       lp([controller-num])

DESCRIPTION
       The lp device driver 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.  To configure such a device, you must add to the DG/UX system
       configuration file a device name entry of the form described in the
       synopsis above.  The parameters in a device name have the following
       meanings:

       ·   The controller-num parameter is a number which distinguishes the
           various instances of the controller that are available.  The
           default value for controller-num is 0, which is the only value
           currently supported.

       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 AViiON
       (Trademark) System Control Monitor (SCM) for more information.

       Select always returns READY for both read and write operations.

FILES
       The lp device creates a single character-special device node when it
       is configured, with the pathname:

           /dev/lp


SEE ALSO
       lp(1).


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