Disk hardware emulation, was Re: Grandfather system RTE6/VM?

From: Eric Smith <eric_at_brouhaha.com>
Date: Wed Dec 10 18:55:34 2003

I wrote:
> The part of the ST-506 disk emulation that's of most concern to me is
> whether anything needs to be done about write precompensation.

Peter Wallace wrote:
> Right, one option would be for the emulator to have a FM, MFM or RLL front
> end
> and actually decode the bitstream. Then the write-precomp could be
> undone...

You can undo precomp without doing FM, MFM, or RLL decode, and in fact
remain completely format-agnostic. You just have to model the peak-
shifting that the real drive would perform. This could be done either
during write, or as the data is read back.

If you did decode the data, it would reduce the storage requirements of
the emulator considerably, but it would make it a lot less general-purpose.

Eric
Received on Wed Dec 10 2003 - 18:55:34 GMT