Mastodon Feed: Post

Mastodon Feed

Boosted by jsonstein@masto.deoan.org ("Jeff Sonstein"):
cliffle@hachyderm.io wrote:

Ran across this gorgeous diagram (at left) of the cyclic execution schedule of the software used on Skylab (1970s). I love this way of thinking about cyclic execution, but I didn't realize anyone else used it!

At right, one of my (less pretty and much less hand-drawn) diagrams from an article I wrote on graphics demo architecture... 40 years later. (And ten years ago, gosh.)

In the replies below, I talk about the old ways of drafting, if you're curious.

A diagram labeled "16 K FLIGHT PROGRAM COMPUTATION CYCLE." It's a circle, divided into five sectors radially and six tracks around the circumference. Over the course of the cycle different patterns are shaded in, which map to a legend in the lower left distinguishing between I/O, telemetry, self-test, wait states, and two priorities of loop.
A circular diagram of operation timing and priority during a 26.4 µs VGA scanline. Priority levels of execution are represented as rings of increasing radius, so low-priority computation is on the inside, and "hops up" to higher priority levels as required.