Follow

All about floppy formats, from the lowest levels. Do you know your FM and MFM? Can compare Apple's with 's? Understand the difference between flux density and data bit density? Remain calm while discussing zoned recording and sector gaps? Can you write a track at a time? Can you flip a floppy? These are all important life skills these days, so click through and read André Fachat's treatise, especially the diagrams.

extrapages.de/archives/2019010

via cbm-hackers list

@EdS Next step: generating 'error sectors' as a copy protection mechanism like in the old days. :-)

@EdS that's a really nice article; I never had to worry about bit encoding (especially coming from a been world where the FDC did everything for me). But his calculation of 1.542 inch for the radius to the first track makes me wonder if that's how the CBM drive got it's number

@EdS Also worth noting that this only covers the earlier 13-sector Apple format, not the 6-and-2 encoded 16-sector format adopted with Apple DOS 3.3 in 1980.
Sign in to participate in the conversation
Mastodon @ SDF

"I appreciate SDF but it's a general-purpose server and the name doesn't make it obvious that it's about art." - Eugen Rochko