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PLATO Notes: Original Development

In the summer of 1973, Paul Tenczar asked me to write a program that would let PLATO users report system bugs on-line. Tenczar was the head of the system software staff, and I was a 17-year old university student and junior system programmer. I had been with CERL for about a year, learning the ropes and doing minor programming tasks at minimum wage.

We already had a way for users to report bugs, but it was just an open text file called "notes". Anyone could edit the file and add a comment to the end. After investigating a problem, a system programmer would insert a response (typically something like "+++Fixed - RWB").

This was simple enough, but there were problems. For one thing, only one person could edit the file at a time. For another, there was no security at all. It was impossible to know for sure who had written a note. Most people signed or at least initialed their comments, but there was nothing to enforce this. And occasionally some joker would think it was fun to delete the entire file.

It was just such an incident that prompted Tenczar to ask me to develop a replacement. His idea was a simple refinement of the method we had been using: a user would type a problem report into a special-purpose program, which would automatically tag it with the date and the user's ID and store it safely in a tamper-proof file. The same program would allow convenient viewing of the stored notes. Each would appear on a split screen, with the user's note on the top half and the system staff's response below.

It occurred to me that half a screen might not be enough space for some notes. And that some problems might require back-and-forth conversation between a user and the system staff. A limit of one response per note wouldn't permit much dialog.

I came up with a design that allowed up to 63 responses per note, and displayed each response by itself on a separate screen. Responses were chained together in sequence after a note, so that each note could become the starting point of an ongoing conversation. This is what John Quarterman calls a star-structured conferencing system, and PLATO Notes was apparently the first of its kind.

My first prototype kept all notes in one file. Upon entry you would see an index of the most recent notes, listing each note's number, date, title, and number of responses. You could then select a note to read, or page back through the index to find older notes.

As I showed this to other members of the system staff, we began to talk about other ways that this program might be used beyond just problem reports. We thought it would be nice to have a separate area where new users could ask questions and get help from more experienced users, and another area where the system staff could announce new PLATO features. So I added a top-level menu to let people choose among three notesfiles: System Announcements, Help Notes, and General Notes.

Notes was released on August 7, 1973. It was named after the text file it replaced, so that people accustomed to typing "notes" would be taken to the right place.

Every note or response appeared on its own screen. Since PLATO was designed for education, its architecture was biased toward carefully crafted full-screen displays. It was easy to place text or graphics at specific locations on the screen, but nearly impossible to scroll text. For Notes, this was both an advantage and a drawback. One nice feature was that the note title, date, time, and author's name always appeared in the same place. After using Notes for a while, your eye "knew" exactly where to look for these things.

On the down side, each posting was limited to 20 lines of text so as to fit on one screen. The only way to overcome this was to write a series of responses, but that allowed other responders to slip in and disrupt the flow. Still, the 20-line limit had the virtue of encouraging brevity.

Most options for reading notes required only a single keypress. While reading a response, for example, one keypress could perform any of these functions (among others):

  • proceed to the next response
  • go back to the previous response
  • go back to the base note
  • skip to the next base note
  • begin writing a new response
There were too many options to list them all on every screen. Most prompts were quite minimal, but a Help key was universally available. It would display a complete list of the options available at any point.

Notes quickly became an indispensable part of the landscape. It appeared just as PLATO was beginning a phenomenal growth spurt made possible by the new mainframe. Although PLATO had been evolving for over a decade by this time, to the new flood of users coming on-line, PLATO without Notes was hard to imagine.

Copyright © 1994 by David R. Woolley

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Copyright (c) 1996 - 2006 Elizabeth Mattijsen
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