Disc reader project -- quick status update

On 12/9/09 8:40 AM, Keith M wrote: There is no need to record every value if it is only a binary signal, you can store the delta time to the next transition. This is the difference on a logic analyzer between 'state' and 'timing' modes. In 'state' mode, you sample and save every signal at each event. In 'timing' mode, a high resolution clock is used to measure the durations of each signal. The argument is how much accuracy is required to accurately describe the flux transition points in time, given the positional jitter introduced by the recording and playback mechanisms, and the distortion that occurs in the magnetic medium depending upon the pulse rate of the recording. Another problem is even though it is using saturation recording, the media may have flaws, or the head may clog due to shed, causing pulses to drop out. Data recovery has to cope with the fact there may be pulse dropouts, sometimes requiring the recovery program to 'wiggle' the head across tracks to try to rub the clog off of the heads.