VP(4)

NAME
vp - Versatec printer/plotter interface

SYNOPSIS
vp0 at uba0 csr 0177510 vector vpintr vpintr

DESCRIPTION
NOTE: This driver has not been ported from 4.4BSD yet.

The Versatec printer/plotter is normally used with the line printer system. This description is designed for those who wish to drive the Versatec directly.

To use the Versatec yourself, you must realize that you cannot open the device, /dev/vp0 if there is a daemon active. You can see if there is a daemon active by doing a vax/lpq(1), and seeing if there are any files being sent. Printing should be turned off using vax/lpc(8).

To set the Versatec into plot mode you should include <sys/vcmd.h> and use the ioctl(2) call

    ioctl(fileno(vp), VSETSTATE, plotmd);

where plotmd is defined to be

    int plotmd[] = { VPLOT, 0, 0 };

and vp is the result of a call to fopen(3) on stdio. When you finish using the Versatec in plot mode you should eject paper by sending it a EOT after putting it back into print mode, i.e. by

    int prtmd[] = { VPRINT, 0, 0 };
    ...
    fflush(vp);
    ioctl(fileno(vp), VSETSTATE, prtmd);
    write(fileno(vp), "\04", 1);

FILES
/dev/vp0

DIAGNOSTICS
The following error numbers are significant at the time the device is opened.

[ENXIO]
    The device is already in use.

[EIO]
    The device is offline.

SEE ALSO
vax/lpr(1), vax/va(4), vax/lpd(8)

HISTORY
A vp driver appeared in AT&T UNIX.

BUGS
The configuration part of the driver assumes that the device is set up to vector print mode through 0174 and plot mode through 0200. As the configuration program can't be sure which vector interrupted at boot time, we specify that it has two interrupt vectors, and if an interrupt comes through 0200 it is reset to 0174. This is safe for devices with one or two vectors at these two addresses. Other configurations with 2 vectors may require changes in the driver.