Re: Write Signal on Disk II Question

I think you are thinking that more data can be encoded than is done with
the present scheme. It might be an interesting achedemic exercise and if I
were you, I'd study the QAM modulation schemes often used in broadband
communications. However keep in mind that there is only 1 write output
control to this drive, there is very limited bandwidth on a floppy
interface and a relatively low signal to noise ratio, so you are very
limited to what can be achieved.

see http://en.wikipedia.org/wiki/Quadrature_amplitude_modulation

I understand the limitation. Most copy-protected programmers always
write disk bytes to the disk using more than two adjusted zero bits
reliably. Then, the copy-protected disk runs using read sequencer without
any problems. Most crackers are unable to read more than two adjusted zero
bits by attempting to copy to the destination disk. Is it true?
Do you know any special controller card without using logic state
sequencer ROM may be able to read all presence pulses and absence pulses
reliably? All presence pulsea and absence pulses can be written to the disk
reliably using special controller card. Do you know if it exists?

Bryan Parkoff


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Relevant Pages

  • Re: Write Signal on Disk II Question
    ... sequencer ROM may be able to read all presence pulses and absence pulses ... All presence pulsea and absence pulses can be written to the disk ... I don't know a controller CARD, but I can think of a trick with the ...
    (comp.sys.apple2)
  • Re: Write Signal on Disk II Question
    ... sequencer ROM may be able to read all presence pulses and absence pulses ... All presence pulsea and absence pulses can be written to the ... Do you want to copy the disk to another disk or do you want to make an ...
    (comp.sys.apple2)