Talk:PLATO (computer system)

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passwords on Plato and Lotus[edit]

When you log in on Plato IV, you see a random number of Xs for each keystroke of your password. I was tickled to see this in Lotus Notes. Does anything else now use that gimmick? —Tamfang (talk) 08:12, 27 May 2008 (UTC)

PLATO didn't actually use a Random number of Xs. The random number generator cosumed more processing power than was necessary. Instead the number of X's was based on a couple bits within the internal representation of the letter the user typed. Larryw24 (talk) 10:31, 29 May 2009 (UTC)
Oh. Well, thanks for letting me cling to that illusion for another year. ;) —Tamfang (talk) 17:02, 2 June 2009 (UTC)
Larryw24's description is not correct. It's true that the random number generator was not used, but it wasn't based on the internal code of the character since that would be deterministic. Instead, the low order bit of the current system time (in milliseconds) was used to choose between 1 and 2 X's. I wrote that code, and I just checked it to make sure my memory is correct. Paul Koning (talk) 18:40, 2 August 2012 (UTC)
Yay! —Tamfang (talk) 23:01, 19 August 2012 (UTC)

Plato in K-12 education[edit]

There is no mention of the use of the Plato system in grade schools and high schools. I went to Booker T. Washington Grade School in Champaign and was on the Plato system in Kindergarten, 1st grade and 4th grade especially. In 4th grade, I remember playing the math games to learn fractions and test my basic addition/subtraction/multiplication/division through cutting pizzas, making monster juice and various math races, among other games . . . all using a touchscreen - unheard of for years to come. I also first experienced the film player capabilities and heard the first talking Plato machine.

At the University High School at UIUC, Plato was a natural part of our life. We had classrooms and labs. It was mandatory to learn the BASIC language and program via Plato, as well as have various sign-ons at different levels - author mode, user mode, etc. We spent a lot of free time chatting to others around the world and playing two-player games via the Plato system.

I think the value of how how Plato was used for education is very important. Does this topic deserve its own page, or should it be a paragraph on the main topic page? (Not that I am completely qualified to write it, but I am willing to help.) —Preceding unsigned comment added by Sbwinter2 (talkcontribs) 03:57, 24 March 2009 (UTC)

You used BASIC on Plato?! What year(s) was that? —Tamfang (talk) 06:26, 25 March 2009 (UTC)
It was while at Uni High in Urbana in 1979/1980. —Preceding unsigned comment added by Sbwinter2 (talkcontribs) 16:50, 29 March 2009 (UTC)
A TUTOR lesson ('basicx' if I remember right) allowed users (like Sbwinter2 above) to type in short (up to 90 lines) basic programs. It could 'compile' these programs into an internal P-code and execute the users's BASIC program by interpreting the P-Code. It was designed by Axel Schreiner who, at the time, was a Computer Science PhD student of Professor H. George Friedman. Later Schreiner was on the faculty of University of Ulm. I believe BasicX was operational by the fall of 1973. I was an undergrad student at that time and assisted in the development of basicx. Larryw24 (talk) 10:24, 29 May 2009 (UTC)
We visited Schreiner in Ulm in 1975, for whatever that's worth. —Tamfang (talk) 17:06, 2 June 2009 (UTC)
It certainly suggests that that's where he was. (talk) 12:51, 14 May 2014 (UTC)

I was also using PLATO in grade school, at South Side Elementary in Champaign, from 1978 to 1983 or so when South Side closed. After that I continued to use PLATO in my dad's office in the Math department, then at Uni High 1984 to 1990, for things like US History and more advanced math. The games were a wonderful way to learn basic math skills. Make-A-Monster, Pizza Factory, How The West Was One Plus Three Minus Two (or whatever the numbers were), all made learning fun. Does anyone know if this was one of the earliest uses of computer education in elementary schools? Either way, it was a major part of the system. The list of educational games was one of the longest lists of program types. Hmm...a lot of them were written by...Shannon Dougdale? Something like that, anyway. I think. Anyone know? Critterkeeper (talk) 21:39, 20 August 2011 (UTC)


Minor point: I believe talkomatic allowed 5 users to talk to each other simultaneously, not 6 as the article currently mentions. Talkomatic had roughly 5 channels. Each channel could hold roughly 5 (I believe it was exactly 5) conversants. The conversants could type simultaneously, and, on a per-character basis, their text would appear on the other conversant's screens. It was also possible for people to look in ("monitor") a channel without talking. People sometimes used the monitor feature when a channel was full. Monitoring could also be used when the channel was not full. Channels could be locked, for private conversation. There was also (possibly later) something called "minitalko". I do not remember exactly what that did. - ATBS 19Aug09 —Preceding unsigned comment added by (talk) 10:15, 19 August 2009 (UTC)

Argh, now I'm trying to remember what 'minitalko' was, and the memory is just out of reach! —Tamfang (talk) 17:01, 19 August 2009 (UTC)
Thinking about that a little, it seems like minitalko might have given exactly one channel of talkomatic. It also seems like the inspect code to minitalko was open, intentionally, so people could clone it. I seem to remember it did get cloned a few times. But I am not at all sure about any of these things - I mention them because maybe they'll jog someone else's memory. Who wrote talkomatic, anyway? -- ATBS 20Aug09 —Preceding unsigned comment added by (talk) 11:19, 20 August 2009 (UTC)
Later: there is good talkomatic info here: (including confirmation that there were only 5 channels). According to that page, Doug Brown wrote talkomatic. - ATBS 20AUg09 —Preceding unsigned comment added by (talk) 11:26, 20 August 2009 (UTC)
It'd be nice if talkomatic had its own wikipedia page, especially in light of Google Wave. An article on right now glorifies Google wave for having communication where other people's keystrokes show up in real time. Genius or not, talkomatic had that 35 years ago. (talk) 09:34, 28 October 2009 (UTC)ATBS
Talkomatic was also different from "talk", which sent a one-line message across the bottom of your screen, like bitnetting. --Bluejay Young (talk) 23:11, 24 April 2014 (UTC)

internet PLATO?[edit]

[1] = same thing or not? —Preceding unsigned comment added by ILoveSky (talkcontribs) 01:00, 7 May 2010 (UTC)


First time I've done this but a request was posted by Kraftlos (talk · contribs) and I figured I'd give it a crack. I've given the article a C rating. There's lots of good material and it appears to be well cited. Some of the sections are long-winded. The External inks section needs to be thinned (see WP:EL). Organization of the article could be improved - I'd start by introducing some sub-headings. The article feels heavy on historical information and lighter on description of the system, capabilities and uses and other such facts. This is the first time I've heard of PLATO so don't feel comfortable giving an importance rating. --Kvng (talk) 21:31, 4 July 2010 (UTC)

My feeling is that it has a low importance rating, although this could be challenged if it is shown that PLATO produced a large base of ideas that resulted in later systems and products, as did the hardware and software developments at Xerox PARC. I first encountered PLATO while an undergraduate engineering student in the mid-1970s and was not favorably impressed. The educational material seemed rather shallow and even to the casual observer it was clear that developing educational material for the system was too expensive and time consuming — the average college instructor or professor would find it cumbersome and inefficient, compared to presenting lectures and distributing printed handouts. The hardware that I saw at the time also rubbed me the wrong way. It consisted of rather low-resolution neon-orange plasma displays with simple on-off capability per pixel, rather hard on the eyes compared to typical cathode ray tubes of the day or paper printouts. Neither students nor instructors flocked to CDC's cause, even though the university I attended used a Control Data mainframe for batch processing of academic programming assignments and exercises.—QuicksilverT @ 17:31, 27 August 2010 (UTC)
The PLATO network introduced a number of technologies that later evolved into now familiar concepts we use on the Internet. I grew up with instant messaging in 1980 (I'm not sure when it was actually introduced, I was 4 when I first got to use my dad's terminal) - this was almost 2 decades prior to AOL Instant Messenger. There were a number of other technologies that were first introduced on the PLATO network. If your experience was merely that of a student rather than an end user, I could see how you may have missed out on a lot. Personally, I feel that this article needs to be greatly expanded to properly document how revolutionary this was for the time, and how it shaped our Internet experiences today. I missed having a touch screen monitor that was part of the 2nd generation terminals until last year when I got one with my smartphone and tablet. — Preceding unsigned comment added by (talk) 14:12, 19 July 2011 (UTC)
The comments about the merits of the educational material may well be valid, though it may depend on the subject area. Also, while it wasn't all that successful in a university setting, it was quite successful in more specialized applications such as the training programs of the US FAA, which remained in operation until around 2005. The merit of PLATO as a source of "a large base of ideas that resulted in later systems..." isn't in the academic ("courseware") area, though. Instead, it is in multi-user interactive applications, social media, and games. For example, as was pointed out, Lotus Notes is a direct descendant of PLATO Notes (both in what it does and who created it). Paul Koning (talk) 18:45, 2 August 2012 (UTC)

Question about upper/lower-case letters[edit]

I notice that a lot of program names are written in lower case letters. Why is this the case? SharkD  Talk  03:41, 8 September 2010 (UTC)

All filenames were lowercase. —Tamfang (talk) 10:00, 10 September 2010 (UTC)

Password security bug[edit]

I was at U of I 1974-78, and I remember an event when a bug was discovered in the password system. I'm foggy on the details, but this is what I recall (some or all of which may be incorrect): There was a special password which gave privileged access, sort of a "root" password. Surprisingly, this password was well known, but it contained a special character (0x00 I think) which could not be typed because there was no such key on the keyboard. A password consisted of ten 6 bit characters which were packed into a 60 bit word and subtracted from the "root" password. If the result equaled zero, the passwords matched. After some time, someone discovered that, because the CDC was a 1's complement machine, the 1's complement (logical NOT) of the root password also passed the test! When this pseudo-password was subtracted from the root password, the result was all 1's, which is "negative zero" on 1's complement machines, as since negative zero equals zero, this password gave privileged access too. There was some kind of scramble at that point to change the password and/or fix the flaw in the algorithm.

I'd be interested to know how much of this I'm remembering correctly and any more details about the event. I don't know if this discovery was made by an insider or a malicious attacker; if the latter this was probably one of the earliest computer intrusions based on a security flaw. In any case it might be a good addition to the article.

Mnudelman (talk) 18:36, 18 May 2012 (UTC)

Got sources? Yworo (talk) 14:43, 20 May 2012 (UTC)
No, no sources, only memories. I'm hoping someone can find a reliable source for this incident. Mnudelman (talk) 18:50, 28 June 2012 (UTC)
Very interesting. I suspect this has to do not with passwords (which are hashed and don't have leading zeroes) but the "editing codeword" -- essentially a file password. Those are stored in the clear in file metadata. Some special values, like "no access", or "can be edited by members of group s" were encoded by specific strings with leading zeroes, which could not be typed since all typeable characters are non-zero.
I just looked at the code that checks the user-supplied codeword with the file codeword. It does an XOR (not a subtract) of the two values and looks for zero, but there is an explicit check there to catch the "complement case" -- the scenario you mentioned. The oldest copy of the relevant files I have is from around 1978. It's quite possible that the check I see was not originally there and it was added as a result of the discovery you mentioned; I can't tell from the available data. I also have a document that discusses changes to the PLATO system between 1972 and 1976; it doesn't seem to be mentioned there.

If you can come up with any more details, that would be interesting. Paul Koning (talk) 19:20, 2 August 2012 (UTC)

Well, I left U of I in summer of 1978 and I'm pretty sure this incident was at least a year before that, but definitely not before early 1975 when I started using Plato. I'd guess that the extra check for the complement case that you're seeing was added after the incident. "Leading zeros" does ring a bell, but I haven't been able to remember any other details that might help. Too bad it's not mentioned in the change list. Mnudelman (talk) 16:14, 19 August 2012 (UTC)


Does it bother anyone else that the lead-in image for the article, the PLATO screen shot of the fractional distillation lesson, is green? (talk) 19:26, 4 May 2014 (UTC)

Possible misunderstanding[edit]

Consider the following paragraph:

"Built on a CDC 1604, given to them by William Norris, PLATO III could simultaneously run up to 20 lessons, and was used by a local facilities in Champaign-Urbana that could enter the system with their custom terminals."

The opening phrase suggests that a CDC was used to write the software, but perhaps it's meant to say that this implementation was designed to run on one.

"20 lessons" could mean a variety of ways of counting "lessons".

"a local facilities" makes no sense.

"enter the system with" suggests that the terminals could be used to administer the software, or the courses, whereas the probable intent is to say that students could interact with the computer running PLATO via certain terminals.

"custom terminals" leaves open the question of who designed and made the terminals, and whether they were only usable for this one application. (talk) 12:42, 14 May 2014 (UTC)