Re: Write Signal on Disk II Question

["Michael J. Mahon" <mjmahon@aol.com>]

ferdimh@gmx.de wrote:
> >    Are you saying that you try to build a software program to record all
> > read pulses from the IBM-PC parallel port?  x86 machine is too fast to
> > capture all read pulses from the Apple II disk and put all read pulses into
> > binary image.  Flowing read pulses through read signal is limited to 2 MHz.
> >
> > Bryan Parkoff
>
>
> I don't try to build it, I just suggested it.
> And yes, the x86 machine IS much too fast. But if I let it do some
> nonsense calculations, one can slow it down to any speed wanted. So it
> is possible(IMO) to do a much better timing than the original apple ]
> [ with its fixed clock.
> PS: the data to the disk drive is clocked at 250kHz, not 2 MHz.

The parallel port of any PC is, however, quite slow.  Processor
speed is largely irrelevant.  Port speed is fixed.

It is necessary to sample the disk read signal at 2MHz to
capture the 1us read pulses reliably.

-michael

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