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joe_stanton
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Joined: 09/02/2007
Micro PLATO vs. Central PLATO

The reason why most games from the central system of PLATO did not migrate to Micro PLATO has to do with the differences in both the programming language and the method of delivery.

Central system PLATO has intrinsic support for the multi-user paradigm. Micro PLATO, at least the version I used extensively between 1980 and 1985, had minimal support for a file system at all and had no real network available, let alone intrinsic support for multiple users. The multi-player games on PLATO typically required the use of a "common" disk file loaded into shared memory on the mainframe. Each common could allow hundreds of users to access it "simultaneously" (via mainframe time-slices). The speed of access was and is quite fast and the games relied on this. The programming language, TUTOR, realized access to the "common" data by mapping that memory into re-defineable "nc" variables. This allowed the programmer to simply partition the shared memory "common" as they needed for N number of users. There was no practical way, at that time, that a 4Mhz Z80 processor could have managed to share memory across even 2 or 3 terminals, even if someone created a dedicated shared-memory server, and custom communications hardware (such as an RS-232 network) the latency/lag would be on the order of several magnitudes (guessing) slower and so render the original central system game design unworkable. Games would have had to be completely reworked for the Micro TUTOR language and likely downgraded.

CDC was in the business of primarily selling hardware, big iron, they were also not interested in games at all. The games that CDC did publish with distribution of a PLATO license were reworked to include some small measure of educational content. Micro PLATO was seen by some at CDC as a threat, and after much political infighting PLATO lost and with it Micro PLATO. During and after all that brouhaha several other companies fielded versions of PLATO-like systems with TUTOR-esque languages. These companies were, to name a few, Regency Systems (USE language), GIST (ACCORD Tutor), Computer Teaching Coporation (TenCORE). The one that came closest to delivering real PLATO with less than Cyber hardware was the GIST solution. Signon to Cyber1 and read some of the notes in the notesfile "tutornotes" that discuss some of those if you would like.

Employed as a instructional materials programmer (courseware developer), I was also an active game progammer in the various TUTOR languages but my interest was always in arcade gaming so the shared memory loss did not detract from my experience. Many game programmers from the PLATO era migrated (remember our timeframe here as being the early 1980's) to programming assembly language for Apple II's and then PC's.

Today I am on the system staff at Cyber1.org helping to preserve this incredible living historical museum/system, which can claim so many firsts in the computing world. I also still dabble in the TUTOR language and have done some game programming as well (=asteroids= so far, with =scrabble= following, and some work on modernizing a few others).

Joe Stanton
stanton/s/cyber1

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