Graphon 250 X driver.

INTRODUCTION

The code in this directory was written to be hooked into the back end of an
X 10.4 server. The code provides an interface between the X server and
a Graphon 250 terminal.

OS DEPENDENCIES

This library was written for X running on a standard ATT 5.3 Unix system.
There are only a few 5.3 dependencies that I am aware of.

Code that deals with the tty device hooked to the Graphon terminal is
dependent on 5.3. Change this for 4.2 BSD systems. 

In packet.c there is code to fire off a child process. This process reads
the Graphon terminal device and retransmits the data to a stream which
is, in turn, read by the main X server. This is necessary because at present
there is no streams based tty driver available. A stream is needed to implement
the select wait in the main server.

For 4.2 BSD systems the tty device can be read directly since ttys work
with the select call.

SETUP

I haven't had time to write code that initialized the Graphon terminal. For
now you have to do this by hand by using the Setup key on the terminal.
Here is a list of the changes that need to be made. The label refers to the
Setup screen that contains changes.

	Comm:
		Set port to not obey xon/xoff. Set port to accept NULs.

	Fn Keys:
		Unshifted function keys are user definable.

After you change these items you can go back to the Directory screen and
save the changes if you don't want to enter them every time you power up
the tube.

FUNCTIONALITY

Here is a list of the non functional parts of the driver to date:

	Tile always uses the same pattern and the function codes don't
	work right.

	No masked rops.

	Can't read back bitmaps.

	No check made for running out of bitmap storage in the terminal.

	Line styles not implemented, some function codes don't work.

	Only fixed pitch fonts.

	Cursor not fully implemented.

OTHER STUFF

You will either have to implement my debugging call 'Log' or invent your
own.

AUTHOR

Grant Munsey
Manticore, Inc.
