The BBC Micro, one of the most popular 8-bit micros in the UK, contained a teletext decoder chip, the Mullard SAA5050. (There was an addon available that would

The BBC Micro, one of the most popular 8-bit micros in the UK, contained a teletext decoder chip, the Mullard SAA5050. (There was an addon available that would let you display Ceefax pages displayed over the air with it; for a while they even broadcast programs using the Ceefax system, which you could download.) It was mainly used as a cheap and cheerful display mode, as it consumed a mere 1kB of video memory and got you fast, colourful, chunky graphics, and at the same time gave an entire generation detailed knowledge of the innards of the teletext system: https://www.youtube.com/watch?v=IqzkGkIrbd8 https://www.youtube.com/watch?v=IqzkGkIrbd8 It was a pig to program for: it was (mostly) just a simple 40x25 array of bytes, one for each character. Special effects were done by using command bytes, which showed up (mostly) as a space. So, to change the foreground colour to red, you used a 129 byte. But that used up a character. Getting good effects took skill. Notice the way in that game the colours are separated by line? That's because there'll be two control bytes at the beginning of each line, one to set the colour and one to set block graphics mode, and the visible portion occupies the other 38 characters...