Path: utzoo!attcan!uunet!decwrl!bacchus.pa.dec.com!deccrl!crltrx!jg
From: jg@crl.dec.com (Jim Gettys)
Newsgroups: comp.windows.x
Subject: Re: printing at X terminals
Message-ID: <5849@crltrx.crl.dec.com>
Date: 19 Jul 90 13:16:53 GMT
References: <63035B33DC3FC0AEAA@fccc.edu>
Sender: news@crltrx.crl.dec.com
Reply-To: jg@crl.dec.com (Jim Gettys)
Organization: DEC Cambridge Research Lab
Lines: 53

>>The practical issues are important too.  X could provide a standard for local
>>input/output.  An input/output extension for a simple byte-stream protocol
>>is all that's needed.

>I agree.  I think support in the X-protocol for the "workstation" --
not in the
>sense of a computer with disk drives and other concerns, but the thing
>that sits on the users' desk -- is entirely proper.  I agree that
anything which
>reduces wiring (hard or soft) is a plus.  If I put an X-terminal on my
>desk, it seems to me that a local I/O port is an obvious adjunct to the
>"workstation".  The fact that so many people have local printers (as well
>as other devices) certainly speaks to its practical uses.  Why wire separately
>for it?  The comparison with a local disk drive is not reasonable -- the
>physical proximity of a disk drive is rarely an issue -- the physical
>proximity of printers often is.

One "wires seperately for it" for long term software maintenance reasons.
If two functions (to use two examples, file systems, and X display services)
do not interact closely, then you should build seperate interfaces, so
that as parts of the system grow, change, or are found unnecessary, you can
change those parts of the system with out having problems with all the
encumbering
baggage.

>The fact is that there is a demand for local device access through X
>workstations.  That demand is being addressed in an ad hoc fashion by vendors.
>Whether addressed by an X protocol extension or some other way, I think it
>appropriate that the X-community address the issue.  Ducking it by declaring
>it a non-issue for the user interface doesn't make it go away, it merely
>leaves it in many different - and sometimes less qualified - hands.

This is an argument for people to get together and agree on standard
interfaces.
I have no problem with this argument.  I have major problems with the
conclusion
you draw from the argument.

The problem comes when you say "make it part of the X protocol" directly.
Printing on attached serial devices (even if you believe these are rational,
given network based printers these days...) has nothing to do with X.  Make
it a seperate protocol.

An example of this is XDMCP, the display manager control protocol.  Having X
terminal manufacturers (those silly enough to have serial ports) get together
and agree on a standard protocol for accessing those serial lines seems
sensible
to me.  I suspect it can be as simple as "access this TCP port and start
sending
and reading bytes", and maybe another port for modem control commands.

But making it an X extension seems like folly to me.  KISS the server!
			- Jim Gettys