Re: Write Signal on Disk II Question

ferdimh@xxxxxx wrote:
A good idea, however it won't work if you start/end the writing in the
middle of a sector. The rotation speed is not constant enough to "hit"
the exact same bit the next time around. So you will need to start/end
the write in a gap. This means you have to detect gaps. Also, nibble
counts won't be exact without taking extra measures. So the idea of
doing this entirely "dumb" is probably not workable.

--
Linards Ticmanis


Since we would be able to read the data into the apple, why can't we
then detect gap 1?
According to "Beneath Apple DOS" this is at least 40 FF self sync
bytes. If we detect those the second time, we need to quickly turn of
writing, seek to the next track and continue there.
I don't know why this shouldn't work.
PS: "Beneath Apple DOS" says that one bit is 4us long, i.e. the data
rate is 250kHz. And my Oscilloscope says the same.

Right, but each "1" shows up as a 1us pulse on the read data line.

-michael

NadaPong: Network game demo for Apple II computers!
Home page: http://members.aol.com/MJMahon/

"The wastebasket is our most important design
tool--and it's seriously underused."
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