Den Fri, 4 Jan 2019 18:46:14 +0000 skrev smf <smf@null.net>: > http://amigadev.elowar.com/read/ADCD_2.1/Hardware_Manual_guide/node0194.html > > 8 FAST Value of 1 selects two microseconds per bit > cell (usually MFM). Data must be valid raw MFM. > 0 selects four microseconds per bit (usually > GCR). Side track: The older versions of the hardware reference manual really gives away how long time it took from starting Amiga development until a product were available on the market, because the manual refers to Apple II as an example of what GCR is useable for. > When Amiga Technologies started fitting high density floppy drives to > the A1200 someone put together a package that used gcr at the higher > mfm clock, which (if you used high density media) was supposedly > reliable enough to store more than the standard amiga low density > (880k), but less than the standard amiga high density (1.76mb). I > never tried it, I had an external dual speed drive that worked with > standard format high density disks, but I think it worked out at > approximately 1.46mb. > > It's here if you're interested > http://aminet.net/package/disk/misc/HiDensity It's a shame that Commodore didn't do this themself right from the point where 3.5" HD drives started to become available. > Your "half cells" sounds like you're doubling the bit frequency, but > then saying it's the same. The frequency will only be doubled if there are any bitss where the bitss value differ to both adjacent bits values. And there are no such bits in MFM (except for whatever noise that ends up on the disk when writing is turned on/off, of course, but that's not the point). -- (\_/) Copy the bunny to your mails to help (O.o) him achieve world domination. (> <) Come join the dark side. /_|_\ We have cookies.Received on 2019-01-05 23:02:24
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