| 摘要 |
A sequencer map is disclosed which combines a data field and a next-address field into a single field to thereby reduce the word length of instructions required to operate a magnetic disk drive. The combined data and next-address field has two different functions. In one mode, the combined data and next-address field contains a condition code and a next-address. The condition code identifies a condition and instructions to go to a next address in the sequencer map depending on whether the condition is met. In this mode, the next address to be carried out if the condition is met is contained in the combined data and next-address field. In a second mode, the combined data and next-address field is used to store information which is then output for comparison to information read from the disk, or for writing onto the disk during formatting, or which is not used. One or more bits in the sequencer map determine whether the combined data and next-address field is being used as a condition and next-address field (mode 1) or a data field (mode 2).
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