Quote:
Originally Posted by theducks
the 5.25 floppy discs for a Lisa were $20 (they had 2 head windows instead of 1) EACH
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That, for you young ones, is the media. Not the drive. Very much later you could buy 3.5" drives for a PC at $20. All my 5.25" floppies had two head windows. I never saw any sort of floppy with only one head window (8", 5.25", 3.5" and 3"). Some drives only had one head so people cut a second notch (a taped over notch was write protection). You had to flip the disk to use the other side 100k on an Apple II floppy, assuming you added a notch. Other computers had 180K or 360K and the Victor 9000 / ACT Sirius I (in UK before IBM PC) used the same floppies as 360K on an IBM PC to give 1.2M Byte by varying the speed. Later PCs had higher density floppies at 1.2M which could read the 360K floppies, but if you wrote to them the original PC might not be able to read them. The 3.5" were 720K on the PC, then 1.44M. The Amiga formatted a bit extra on the 1.44M. There was also a last gasp 2.88M 3.5" apart from various floppy sized discs that were not (the infamously unreliable Zip drive and the incredibly reliable MagnetoOptic drive (128M and 256M disks that could survive magnets or washing machines as the magnetic field only flipped a bit heated by the laser).
In 1983 we still used an Intel ISIS II development system with interchangeable Hard Disk platters in a drive about the size of desk height filing cabinet. A Jupiter Ace Home Computer with cassette was used at that time to control some test gear. It had 1K RAM and the cassette as storage. Could run PacMan written in Forth.