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@(#)vp.4 4.1 (Berkeley) 05/15/85

C 4 vp - Versatec interface device vp0 at uba? csr 0177510 vector vpintr vpintr The Versatec printer/plotter is normally used with the programs vpr (1), vprint (1) or vtroff (1). This description is designed for those who wish to drive the Versatec directly.

The Versatec at Berkeley is 36\*(rq wide, and has 440 characters per line and 7040 dots per line in plot mode (this is actually slightly less than 36\*(rq of dots.) The paper used is continuous roll paper, and comes in 500' rolls.

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 ps (1), or by looking in the directory /usr/spool/vpd. If there is a file lock there, then there is probably a daemon /usr/lib/vpd running. If not, you should remove the lock.

In any case, when your program tries to open the device /dev/vp0 you may get one of two errors. The first of these ENXIO indicates that the Versatec is already in use. Your program can then sleep (2) and try again in a while, or give up. The second is EIO and indicates that the Versatec is offline.

To set the Versatec into plot mode you should include <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 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

'nf int prtmd[] = { VPRINT, 0, 0 }; ... fflush(vp); ioctl(fileno(vp), VSETSTATE, prtmd); write(fileno(vp), "\e04", 1);

N.B. : If you use the standard I/O library with the Versatec you must do

setbuf(vp, vpbuf);

where vpbuf is declared

char vpbuf[BUFSIZ];

otherwise the standard I/O library, thinking that the Versatec is a terminal (since it is a character special file) will not adequately buffer the data you are sending to the Versatec. This will cause it to run extremely slowly and tends to grind the system to a halt.

/dev/vp0 vfont(5), vpr(1), vtroff(1), va(4) None. The configuration part of the driver assumes that the device is setup to vector print mode through 0174 and plot mode through 0200. Since the driver doesn't care whether the device considers the interrupt to be a print or a plot interrupt, it would be preferable to have these be the same. This since the configuration program can't be sure at boot time which vector interrupted and where the interrupt vectors actually are. For the time being, since our versatec is vectored as described above, we specify that it has two interrupt vectors and are careful to detect an interrupt through 0200 at boot time and (manually) pretend the interrupt came through 0174.