Importance

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Abstract

A data transfer circuit for coordinating transfer of data between a host and a disc of a disc drive having a state machine for coordinating with a buffer controller to transfer data between the host and a buffer segment and a second state machine for coordinating with the buffer controller to transfer data between the buffer segment and a disc of the disc drive. Counting circuits count the number of bytes transferred between the host and the buffer segment and between the buffer segment and the disc and provide sector count signals each time a sector of data is transferred into or out of the buffer segment. The sector count signals are received by a buffer manager which includes counters for counting sectors of data transferred into and out of the buffer segment and a comparator circuit that compares the contents of the buffer manager counters to provide a code indicative of the state of the buffer segment to a decoder. The decoder provides pause signals to the state machines to suspend data transfers from the source, host or disc, of data when the buffer segment is filled to capacity and to suspend transfers to the receiver, host or disc, of the data when the buffer contains no data which has not been previously transferred to the receiver.

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First Claim