Date : Fri, 04 Oct 1991 17:03:46 GMT
From : orca.cs.wisc.edu!bolo@speedy.wisc.edu (Joe Burger)
Subject: Re: Graphics standard for small systems?
In article <1991Oct4.110905.4392@ips.oz.au> dave@ips.oz.au (Dave Horsfall)
writes:
>Has anyone defined a suitable (portable?) graphics standard for small
>machines? ....
>What I'm looking for is a format that handles most hardware oddities,
>but can run under CP/M without requiring whopping large arrays etc.
>I guess I'll define my own, but I prefer to use an existing one.
>
>Something else that occurred to me while I was typing this was some sort
>of a protocol - a heavily cut-down "X" perhaps - that could be put into
>terminal emulators running remote graphics packages. E.g. you want to
>
I don't know of an existing implementation, but ....
I have been considering such a problem. My answer/intentions
would be to use RMS's/MIT's SUPDUP protocol. It has provisions for both
text and graphics, and is reasonably extendable.
Relevant RFCS are:
749 Telnet SUPDUP-Output option
747 Recent extensions to the SUPDUP protocol
746 SUPDUP graphics extension
736 Telnet SUPDUP option
734 SUPDUP Protocol
The intro from the original RFC is appended to this note.
Another choice might be a version of Bellcore's MGR window system, although
that might require too much space.
Joe Burger
NWG/RFC# 734 MRC 07-OCT-77 08:46 41953
SUPDUP Display Protocol Page 1
INTRODUCTION
This document describes the SUPDUP protocol, a highly efficient display
telnet protocol. It originally started as a private protocol between the
ITS systems at MIT to allow a user at any one of these systems to use one
of the others as a display. At the current writing, SUPDUP user programs
also exist for Data Disc and Datamedia displays at SU-AI and for
Datamedias at SRI-KL. The author is not aware of any SUPDUP servers other
than at the four MIT ITS sites.
The advantage of the SUPDUP protocol over an individual terminal's
protocol is that SUPDUP defines a "virtual" or "software" display terminal
that implements relevant cursor motion operations. The protocol is not
built on any particular display terminal but rather on the set of
functions common to all display terminals; hence it is completely device-
independent. In addition, the protocol also provides for terminals which
cannot handle certain operations, such as line or character insert/delete.
In fact, it is more than this. It provides for terminals which are
missing any set of features, all the way down to model 33 Teletypes.
The advantage over the TELNET protocol is that SUPDUP takes advantage of
the full capabilities of display terminals, although it also has the
ability to run printing terminals.
It is to be noted that SUPDUP operates independently from TELNET; it is
not an option to the TELNET protocol. In addition, certain assumptions
are made about the server and the user programs and their capabilities.
Specifically, it is assumed that the operating system on a server host
provides all the display-oriented features of ITS. However, a server may
elect not to do certain display operations available in SUPDUP; the SUPDUP
protocol is far-reaching enough so that the protocol allows terminals to
be handled as well as that host can handle terminals in general. Of
course, if a host does not support display terminals in any special way,
there is no point in bothering to implement a SUPDUP server since TELNET
will work just as well.
--
Joe Burger University of Wisconsin-Madison Computer Systems Lab
arpa: bolo@cs.wisc.edu uucp: {backbone}!uwvax!bolo
End of INFO-CPM Digest V91 Issue #172
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