On Wed, Jan 2, 2019 at 4:13 PM Francesco Messineo <francesco.messineo@gmail.com> wrote: > > On Wed, Jan 2, 2019 at 3:40 PM André Fachat <afachat@gmx.de> wrote: > > > > Hi there, > > > > I was looking at floppy disk recording schemes and I am wondering if the > > 8050/8250/1001 floppy disk format with over 500kB per side was actually out > > of spec of even the Quad Density disks? > > > > The recording frequency was increased from 250kHz to 375kHz (× 1.5, for the > > innermost i.e. most critical track/speed zone). That resulted in a much > > increased number of bits per inch. See here: > > https://extrapages.de/archives/20190102-Floppy-notes.html > > > > What do you think? > > > > I'm sure you know it, but the best reference I've found on the net > about floppy disk drives is here: > > http://www.retrotechnology.com/herbs_stuff/drive.html quoting from the above link: 8-inch drives, 76 or 77 tracks: track 0 on outer circumference, track 77 near hub. track bit density, innermost track (76 or 77) 3200-3600 bpi for single density, 6400-6500 bpi for double density 8-inch floppies use the same 300 oersted media as SD/DD 5 1/4-inch, so apparently these bpi figures are not really an unbreakable barrier (and probably dependent on the modulation scheme as far as I understand). FrankReceived on 2019-01-04 20:00:38
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