XWINDOWS question

[Guy Harris]

> Can it run under UNIX 5.2 or greater?

Not without some work.  It may use the new reliable signal mechanism from
4.2BSD.  It is a server-based window system; programs running under X do not
directly paint bits on the screen, they send messages to the X server and it
paints the bits.  Furthermore, it does not directly read events from
keyboards or mice either; the server reads them and sends messages to
clients.  As such, it requires a bidirectional interprocess communication
mechanism of some sort; it currently uses UNIX-domain sockets and
Internet-domain sockets.

You may be able to make it use named pipes or message queues.  Note,
however, that one of the major benefits of a server-based window system -
the ability to run programs that use the window system on machines other
than the machine that has the keyboard and display - is not available if you
don't have some sort of IPC mechanism that works *between* machines.  A
TCP-IP based mechanism would be preferable here, as it would permit X to
work with X on other machines, as the other implementations use TCP-IP.

> Does it subsume CGI/VDI software while doing window management

No.  It offers some low-level drawing primitives for drawing lines, and also
offers low-level RasterOp-type primitives.

> or does it make assumptions about some underlying CGI/VDI functions.

No.  OVERlying CGI/VDI functions may make assumptions about IT, however.

X has no direct relationship to CGI/VDI/etc.; I presume one could implement
them on top of X.
-- 
	Guy Harris
	{ihnp4, decvax, seismo, decwrl, ...}!sun!guy
	guy at sun.com (or guy at sun.arpa)