| 摘要 |
PURPOSE:To always obtain a rational data unit having satisfactory coordination secured between old and new types as the read data unit, just by simple comparison between the words read out through two continuous reading actions. CONSTITUTION:The relations TW2<=TR2, TW2<=TR1-TR2 and TW1-TW 2>=TR1+TR2 are satisfied where the writing cycle of the data unit is referred to as TW1 together with the reading cycle as TR1, the writing interval of each word as TW2 and the reading interval as TR2 respectively. Then two reading actions are carried out continuously and comparison is given between the 1st and 2nd read timings M1 and M2 of the 1st word. In case, a single writing action is carried out between two continuous reading actions, for example, the 1st read data unit is validated since the M1 is equal to the M2 is examples (a), (c) and (d). While the 2nd read data unit is validated since the M1 is different from the M2 in an example (b). In any case, coordination is secured between the new data (n) and the old data (o) for both words forming the data unit.
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