Microsoft O.S.

in
Comment from E-mail

Much is made of the history behind apple hardware and Microsoft O.S.'s. Not much is told of the operating system behind the Apple II. Was there one? Was it just Basic?

Woz

There was a disk operating system when we came out with the floppy disk around 1978 or 1979. But the Apple ][ originally had only cassette tapes for storage. It was quite slow and there was no OS function other than to read a program in, which could then read it's own data in.

The level of the original Apple ][ 'Operating System' was that each slot could be assigned a device, which could be communicated with via BASIC. Each slot had a fixed address block assigned. Within those addresses you could include a Driver program, stored in ROM on the card that went with each device. This was true plug and play, with no separate step for driver installations.

A user could switch the printout function to any slot (and the input fuction). By switching the printout to a card that controlled AC power, for example, you could then print commands to the card which it would obey. You could also print to a card that then did other things, like change BASIC languages or switch the display to a card that could handle more characters per line.