by Darius Kazemi, July 5 2019
Rotating cubes on the network
RFC-186 is titled “A Network Graphics Loader”. It's authored by first-time RFC author Jim Michener, who is personnel working on the MIT Project MAC Dynamic Modeling Computer Graphics PDP-10.
The technical content
The Dynamic Modeling Computer Graphics computer at MIT Project MAC had an Evans and Sutherland Line Drawing System Model 1 (LDS-1) vector display. This RFC describes a way for network users to write graphics programs for the vector display, run them remotely, and get output from the program on their local host.
The way this happens is the LDS-1 can dump a list of all rendered line segments to a data format, and this data format is sent over the network. A remote user can send commands like “SETUP the following program, EXECUTE it 3 times, TRANSMIT the image back to me”.
A user might want to execute a program a bunch of times, with minor updates to variables between executions, to create animations, for example:
(It might be programmed to make an object appear to rotate.) The user of the routine typically would want to set up the matrices and then "let 'er rip" with ten or twenty (or more) executions.
As these commands are sent, the DMCG computer sends back “ACKNOWLEGDE” messages so the user can be sure that each message has been received. (Though if there's a problem, an “ERROR” message with a special code depending on the error is returned to the user.)
According to this 1973 Project MAC report, Michener did a ton of graphics-related work.
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I'm Darius Kazemi. I'm an independent technologist and artist. I do a lot of work on the decentralized web with ActivityPub, including a Node.js reference implementation, an RSS-to-ActivityPub converter, and a fork of Mastodon, called Hometown. You can support my work via my Patreon.