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

Generally, yse... Ih, but it does matter... The point of precompensation is tha when you write magnetic transitions to the real disk, they don't end up quite where you expect (this is a sort-of cimplification, but it will do for the moment). So you change the timing of some of the pulses in the bitstream, so that when you write the _modified_ bitstream and read it back you get what you had in the first place (before precompensation). Thus, on reading, the controller sees an _unmangled_ bitstream coming from the drive. By unmangled, I don't mean what was fed into the drive when it was written. I mean what was fed into the precompensation circuit, which might well be part of the controller. Now, the emulator doesn't ever mangle the bitstream. So if you write a precompensated bitstream to the emulator, and then read it back, what you see is the precompensated bitstream, with the timing of some pulses changed. This is not what the controller expects. Maybe it'll work, maybe not. -tony