Ceefax, 1974. A network with no address bar: you reached a service by knowing its number.
Every page in the magazine was broadcast in a continuous loop. Your set watched the signal go past and grabbed yours when it came round. Ask for a page near the end of the cycle and you waited longer. There was no request, so there was nothing to hurry.
That page was not in the magazine, and teletext had no way to tell you so. A request was not a request, so there was no reply and no error. The set simply kept waiting for something that was never in the loop.
The 404 is a courtesy this system could not extend.
Type a word, then add a color before another word. Watch what the color change costs you.
Five cells used. No color changes yet.
France put color in the spec. Most homes had a gray screen, so designers composed for the gray. Flip the switch.
How to spot teletext.
P100 CEEFAX 100 Sat 2 Aug 21:47The header row is 32 columns, not 40
The first eight cells carry control codes that are never displayed, and the last eight are the clock.
NEWS SPORTRagged right edges everywhere
Every color change occupies a real character cell, so text after a color code starts one space later than you typed it.
Double height eats the row below it
A double-height line does not scale, it consumes the next row entirely.
12 × 201 2 4 8 16 64Graphics are made of six blocks per cell
, so every picture is built from nothing but color and absence.
Exactly eight colors
, full-intensity RGB and nothing between: black, red, green, yellow, blue, magenta, cyan, white.
Ceefax ran for 38 years and stopped in October 2012. Minitel, which France gave away to get people online a decade before the web, was switched off in 2012 as well.
Both were slow, and both were free at the point of use, carried by infrastructure that was already there. Neither had an account, a login, a recommendation, or a way to know who was reading.
Information reached everyone at once, with no request, no record and no reader to identify.