Archiving ST-506 drives

On 12/01/2011 02:26 PM, Brent Hilpert wrote: transitions) I don't have an issue with that; that's the way it was written. That you can perform a process that takes non-time-quantized read data signal from the drive and by a "discrete process" produce a time-quantized output that is (usually) the same as the signal that was originally written does not in any way prove that the read data signal data so reliably is exactly the point. That argument could be used to claim that the signal a V.32 modem receives over a telephone line is voltage-quantized, because you can sample it then apply a "discrete process" to reliably get the original data transmitted from the other end. In both cases, if the channel signal was actually quantized (in the time domain for the magnetic disk, and in the amplitude domain for the modem), there wouldn't be any need for a "discrete process" the you describe. examine.) It appears that you've identified the reason we disagree. I would argue that asynchronous (start/stop) serial as received is non-time-quantized, although the clock recovery is much simpler than with a magnetic disk because the channel does not distort the timing by more than a trivial amount in proportion to the transmit rate. A UART does have to oversample the async receive data and use a decision process (generally based on detection of the leading edge of the start bit) to identify the appropriate bit cell boundaries to time-quantize the data. A synchronous serial channel provided with an explicit clock signal is time quantized. Eric