Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!uunet!husc6!bloom-beacon!think!barmar From: barmar@think.COM (Barry Margolin) Newsgroups: comp.protocols.tcp-ip Subject: Re: supdup protocol Message-ID: <9205@think.UUCP> Date: Tue, 13-Oct-87 16:11:45 EDT Article-I.D.: think.9205 Posted: Tue Oct 13 16:11:45 1987 Date-Received: Thu, 15-Oct-87 02:59:48 EDT References: <8710100357.AA04652@drizzle.uoregon.edu> <8710121554.AA07611@armagnac.DEC.COM> Sender: news@think.UUCP Reply-To: barmar@sauron.UUCP (Barry Margolin) Organization: Thinking Machines Corporation, Cambridge, MA Lines: 44 In article <8710121554.AA07611@armagnac.DEC.COM> "Christopher A. Kent" writes: >Some work was done a number of years ago (I can't find a reference, but >it was at Arizona) to investigate how to use a micro to do editing >across a 1200 baud link. I don't think this is the exact paper you are talking about, but it is similar: Judd, J. Stephen, Corinne J. Letilley, "Memory and Communication Tradeoffs During Screen-Editor Sessions", Univ of Saskatchewan, August 16, 1984. Abstract: Screen Editor sessions typically make heavy use of the communication channel between processor and display screen. This is because relatibely simple and quick operations like window movements can cause the transfer of 1000 or more characters. To get a quantitative measure of communication requirements, we need to determine how people use such systems. We accumulated a representative sample of user activity by tracing the movements of the cursor during 1500 editing sessions. Some information about these sessions is presented. To make effective use of an interactive screen editor, the two-way channel between the computer and the screen terminal must have a fairly high baud rate. By simulating the observed sessions at various baud rates, we measured the amount of time lost during such a session if the baud rate is low. Then we estimated the increase in performance afforded by keeping a buffer of text lines local to the terminal. Resultant graphs are suitable for comparing the performance of terminals with various memory sizes and baud rates. We prpose a terminal that takes an active role in the management of text during editing sessions and we estimate its impact on CPU demands in the host. This work has implications for the design of terminal hardware and screen-editor software. --- Barry Margolin Thinking Machines Corp. barmar@think.com seismo!think!barmar