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Hi Pat, You seem focussed on the "extra clocks" during Ultra DMA burst termination. Let's try to take this up a level (or down a level, as the case may be). These are not "extra clocks". This is explained in several places in the standard (e.g., item (d) in 9.13.3.2 Host pausing an Ultra DMA data-in burst), "The additional data words are a result of cable round trip delay and tRFS timing for the device." In other words, if the sender is transmitting data, and the recipient initiates a burst termination, then the sender shall respond to the burst termination as quickly as possible, but this response is not instantaneous. By the time that, a) the termination signal gets down the wire, b) the sender detects that the recipient has initiated a termination, and c) the sender can react to the termination by stopping data transmission, the sender may have already clocked one, two, or three more times. This is perfectly good data. This data will be included in the CRC calculation. The only "arbitraryness" is the result of the inherent asynchronicity of the system and implementation differences. The "one, two, or three" is the result of the cable plant and when the recipient's internal circuitry detects the pause and can react to it. I hope this helps. Please feel free to call or send an email to me with any additional questions that you may have about this. Regards, Mark Evans Maxtor Corporation 500 McCarthy Boulevard Milpitas, CA 95035 USA Tel: 408-894-5310 FAX: 408-324-7432 email: [EMAIL PROTECTED] Subscribe/Unsubscribe instructions can be found at www.t13.org.
