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I have always found it notable and actually significant that the PLATO community first started with Notes, meaning, group communications or message forums, rather than Personal Notes, meaning email. Notes arrived in 1973, and Personal Notes came about in the first half of 1974.

Why is this significant? Well, let's take a look.

In 1973, the early PLATO IV system had no email system yet. But given that the system programmers at the Computer-based Education Research Lab (CERL) tended to work random hours -- some were daytimers, some were night owls --- and their offices were scattered around a five-storey building, the way they tended to communicate online to one another was via a series of TUTOR lessons, just plain source code files, called notes1 through notes19. They used the honor system: anyone could go in and edit the "notes file" but you were expected to be on your best behavior and not delete any existing text, or change anything. The idea was: append your comments, sign it with at least your initials, and get the heck out as soon as possible because nobody else could edit the file if you were in there. As you can imagine, this only worked for a while. On more than one occasion, some joker would go in and mess with the existing questions or answers, or delete the entire text.

Paul Tenczar, one of the senior system programmers, was finally exasperated enough at the situation and at the lack of a real system application for notes that he asked then 17-year-old Dave Woolley, who had only recently wandered over to CERL with classmate Kim Mast, both of them Uni High students, to work in the summer on creating a real system application that had authentication and enabled users to post notes, reply to other notes, and finally solve this problem.

On August 7th, 1973, lesson =notes= was released on PLATO. Initially it supported three "categories": notes regarding new system feature announcements, general notes for the public, and "help" notes, or requests for help.

It was an immediate hit.

What is interesting to me is that PLATO's email feature, Personal Notes, written by Kim Mast, didn't come out for a while yet. And this is where things get interesting vis-a-vis the Internet and the Web. On PLATO, users became acquainted with the benefits of group communication and collaboration -- emphasis on group -- far earlier than they did on the Net. Think about it: ARPANET started with email as early as 1971 (although there were various primitive earlier instances of it on various systems going back into the 60s). Yes, there were experimental message forums on ARPANET from circa 1971, but they were relatively isolated and not "mainstream", that is, everyone didn't use them. On PLATO, pretty much all author-level users were exposed to and participated in the Notes capability, and it became the de-facto method for communicating and sharing ideas with colleagues, among many other uses.

On ARPANET, later Internet, and I would argue even still on the web today --- especially in workplaces --- think about your own situation: do you work at a company with more than 25 people? Do you live in email all day? Does that not describe life in most companies? --- email is the predominant communications tool, not group notesfiles or message forums. Some teams here and there use message boards, some use wikis, but almost everybody uses email as the de-facto standard for group communication, despite how messy and cluttery email is for such purposes. Remember how the media used to talk about the Information Age was one where companies were filled with "knowledge workers"? More like companies have become filled with people dealing with way too much email.

Think about the typical work-related email thread: somebody sends out a note and cc's a bunch of people, and you're on the cc list. Then some of the recipients post replies, replying to all. Then more. And then even more. And usually, everyone "quotes" the previous messages as appended text, so the actual message length keeps growing, even if all you post in your reply is "i agree" or "i disagree". Every single time someone sends out an email reply to all the recipients, they all individually get a new unread message in their inboxes. During the course of a single day, a busy company can cause dozens if not hundreds of new, unread emails, many of which with "Re:" or worse, "Re: Re:" or "Re: Re: Re:" threads in them. It's a productivity nightmare, and yet, this is still the way things pretty much are for most workplaces.

PLATO users lucked out and saw the benefits of using Notes for group communication and collaboration right from the start. In fact, there was no "cc" or "bcc" option in Personal Notes -- it was for you to send a single message to a single recipient, period. Later the capability to forward a personal note to another user was added, but there was no cc list that I can recall (it may have been added years later on NovaNET but then I'm not even sure about that). So PLATO users naturally gravitated to using the group-oriented Notes application (which by 1976 had expanded to support the ability for anyone to create their own "notesfile" and control who could have access to it, making it ideal for private collaboration and discussion among a select group or team).

It is unfortunate that the Internet/Web did not evolve similarly, with a clear delineation between email and group messaging -- or a better architecture right from the get-go that merged email and group messaging. Ray Ozzie and the team at Iris Associates built the wildly successful Lotus Notes, which attempted to take the learnings from PLATO Notes to the networked personal computer arena, but despite its success, in the end it was a proprietary system that only thousands of businesses adopted -- not millions. (Sure, Lotus Notes, now part of IBM, can claim over 100 million end-users, but the Internet has well over 1 billion, soon no doubt to be 2 billion if we're not there already, "end-users". So Lotus/IBM have not changed the way most people communicate.) Today, the default is email, not a group collaboration system. Lots of companies over the years have tried to offer products that change this -- most notably Google's recent Gmail and Wave services, which enable you to think of group communications more as conversations, and conversations are considered atomic items, rather than simple individual messages -- but despite even their success, we are still stuck without a PLATO-style Notes solution that is the defacto standard for the Internet. This is unfortunate and I wish it could change, but I don't see it changing until Google, Microsoft, Apple, Yahoo, and the dozen or so other players who, together, have the majority of worldwide population using their communication tools, to agree on a new standard. And that ain't likely.

An ancient screen shot of the CERL PLATO system's welcome page from 1975.

Long before Google was customizing their home page to celebrate observances, holidays, and such (like they are doing this week with the 2010 Winter Olympics), at a time when Larry and Sergey were still too young for kindergarten, PLATO's welcome page would be customized for various holidays like Christmas, 4th of July, Valentine's Day, Halloween, and Thanksgiving.

Aaron Woolfson has for the past five years undertaken an amazing project: to acquire and restore -- not just clean up, but restore to original factory specifications -- a variety of original PLATO terminals from the 1970s. He's traveled all over the country, picked up parts here and there, and has even had custom parts made.

On January 20, I finally got to meet Aaron. We converged on the Computer History Museum so the museum folks could see a real working PLATO V terminal. The plan is to have, on hand at the conference about half-a-dozen PLATO terminals up and running and connected to the Cyber1.org service. Attendees will be able to try out the terminals and check out original PLATO applications including thousands of educational lessons ranging from anthropology to zoology, as well as the notesfiles, TERM-talk, and of course, PLATO's legendary multiplayer games.

Here are some photos of the terminal Aaron showed off at the museum:

What's especially cool is that Aaron has hacked together an interface such that the terminal thinks it's connected to a 1260-bps serial line, but in fact, is connected to the Internet which it then converts into the old 1260-bps serial signal. For the conference, he's building little interface boxes for each terminal such that all you have to do is plug the terminal into an ethernet cable connected to the Cyber1.org service on the Internet and you're all done.

Recently I received an email from David Dennis, a former PLATO user from Illinois who over the years has shared with me numerous anecdotes. This one was one I'd not heard before, where he describes what he believes might have been the first instance of a "denial of service" (DoS) attack on a computer network.

If there is one thing I've learned over the years, never make an absolute claim of "first" when it comes to anything computer-related, because as soon as you do, someone somewhere will come out of the woodwork with proof of an even-earlier first. So, I eagerly await the onslaught of "no way, I saw a DOS attack years earlier!" comments. But in the meantime, here's a neat story from 1974.

Some quick explanation of terms before I quote the email. First, he's recalling an incident that took place at CERL, the Computer-based Education Research Laboratory, at the University of Illinois Urbana-Champaign. "TUTOR" is the name of the programming language on PLATO. "Author mode" refers to a level of system privileges on PLATO that all authors/developers had. "Went back over to uni" means he went back over to University High School, located across the street from CERL. (Old joke: Why did the Uni High student cross the road? To get to CERL.)

Okay, here goes. From David Dennis:

As far as I know, I'm the first person to have created a DoS of a room full of PLATO terminals deliberately. Systems people could of course kick anyone out they wanted, and "operator wars" had existed for years, but those tended to be consensual attacks on each other. What I did was I heard about a new command called the "external" command in TUTOR, or 'ext'. Specifically, one of the music kids was saying how if you didn't have a device attached, an ext command would cause your terminal to lock up and have to be powered off. Remember that powering off was discouraged, due to always-concern over flaky power to the plasma panels.

The other piece of this was they had rolled out the external command for everyone in the fall of 1974, after it having been only in use by the Music project. This meant that every user account on PLATO was set to defalt "can accept ext commands." Default on.

If you recognize default enabled from any firewall work you'll immediately recognize the trouble...

Anyway, I heard this and immediately thought of how a room full of annoying users could be locked up at once. My little 13 year old brain wanted to see a room full of users all be locked up at once.

So, I wrote a little program that sent exts to everyone within a range of site numbers, waited til I was over at CERL one morning, and let er rip.

It worked as advertised, 31 users all had to power off at once, great mayhem in the classroom, site monitors notified. No logging of course, I was never detected. Quietly left the room, went back over to uni.

Accessed the site displays I knew of from author mode, and looked up other sites around town or the country, and tried sending them some ext's too. Was delighted to see mass posting on notesfiles about a locking out they were experiencing.

Soon some systems guys figured it out, probably a combination of common sense and maybe looking in some sort of logs, though I was never prosecuted or even approached, so I have to think to this day it was undetected. A few weeks later the ext command was withdrawn from 'open all' and a while after that was redeployed, this time with the default set to OFF. As it should have been all along. :)

So was there ever a DoS on a networked system prior to 1974 ? Im sure there had to be, but at least for the moment I'm claiming it !

This is a classic example of how things typically go with software, only this is an example from 1974: release a system to the users, and they will find bugs and vulnerabilities the developers weren't aware of or assumed were harmless. Make changes, release a revised system, and so on. Over time, this is how the PLATO system became more robust and secure.

UPDATE 2/14/2010 -- Welcome, slashdot. Er, one moment while I put out the fire that you're causing with my web server. :-) Let me provide a little more detail on the TUTOR -ext- command, how it worked, etc. Here is the actual page from PLATO's online help system for the -ext- command:

The -ext- command was relatively new in 1974, indeed, it may have been brand-new. It was intended so that you could have your PLATO IV terminal connected to an external peripheral device and control that device using a serial connection. Note how the manual says "only 1 -ext- per second may be sent to another station." Heh, in those days, one per second might be enough!

UPDATE #2 - 2/14/2010 Below is the note on =announce=, the System Announcements notesfile, from 1/2/74, announcing that a change had ben made to the -ext- command (perhaps, not sure, due to the exploit above):

-ext-         Note 1

1/2/74         12:32 am CST         andersen / s

The two argument -ext- command (ext data,station) now checks if the other station wishes to recieve -ext- commands... as with the talk option an author may specify that he wishes to recieve -ext-'s from anyone, from his course only, or not at all..

The -ext- command returns the system variable *error* = -1 if the data was sent or = 0 if not

The one-argument -ext- command is not affected