4 ms·
One thing I've always wondered is why no-one tried to double the track density for read-only floppies. The reason floppies have so few tracks (100000 bits per
by Tuna-Fish 2y ago
One thing I've always wondered is why no-one tried to double the track density for read-only floppies.
The reason floppies have so few tracks (100000 bits per track, only 80 tracks per side!) is that the read-write mechanism didn't track the track. It was just indexed to a specific position by a stepper in the drive mechanism. Because there were a lot of sources of radial position error, and the writing and reading process could be misaligned in opposite directions, the tracks needed to be wide and far apart for reliability, and the erasehead needed to erase a much wider area than what the rwhead could read/write. The various later superfloppy standards that failed to get market traction usually only got slight increases in bit density along the track, and most of their capacity increase from having some way for the rwhead to follow the track, enabling dramatically higher track density. But all those mechanisms would be much more expensive and complicated to do than a simple floppy drive.
But if you use a more precise and expensive machine to write the disk, the normal amount of precision in the drive that is used for reading ought to be sufficient for about twice the track density. The only hw change needed would have been allowing half-step positions for the rwhead, for no cost increase. And I can imagine 80's/90's software devs being interested in a format that is harder to copy at home. Yet no-one ever did it, does anyone know why it was never tried?
- joncrocks 2y agohttps://en.wikipedia.org/wiki/Perpendicular_recording https://en.wikipedia.org/wiki/Perpendicular_recording - Apparently what you're describing > Perpendicular recording was later used by Toshiba in 3.5" floppy disks in 1989 to permit 2.88 MB of capacity (ED or extra-high density), but they failed to succeed in the marketplace.
- Lerc 2y agoI think that is something else entirely, unless you consider that to be the expensive writing version. Adding a little capability (in this case permitting finer stepping) and letting software guys figure it out was often the way to great new abilities. I often think about tiny little changes to old hardware that would have been an insignificant cost but added great functionality. Like a 4 bit latch xored with the rgbi output of CGA would have enabled a huge gain in what colour options were available. It would only be a few gates. You would still only have 320x200 in four colours but the colours available wouldn't melt your eyes.
- Tuna-Fish 2y agoNo, this is about increasing bit density inside a track by placing the magnetic domains in a different orientation. The floppy standard failed, but it became the norm in hard disk drives as soon as the patent on the special rwhead that was needed for it expired.
- philistine 2y agoYour inquiry reminds me of Game Boy. Some 4000 early Game Boy consoles had a specific hardware quirk that limited the refresh rate of the screen under a specific method. For the whole decade of existence of Game Boy, every single game was tested for this specific bug by Nintendo, and a few developers got burned because they wanted to use the refresh method but couldn't. I bet it's a similar situation. Something like 99% of all drives could have handled what you're describing, but the 1% stopped anybody from trying your method.