| 摘要 |
Clearance arrangement for data storage apparatus. Data items D are entered into a store 10 together with a tag T equal to the current value of a counter 11. Data items are valid only while the counter 11 retains its current value. When it is desired to clear the store 10 the counter is incremented so that items with the previous tag value are rendered invalid. On some or all of such occasions a fraction of the store locations are also cleared by setting their tags to a null value. By the time the counter has completed a cycle all locations have been cleared in this way and cannot erroneously appear to contain valid data remaining from the previous cycle. The store is out of action to allow it to be cleared only for a relatively short time. Different tag counters may be used for different data types. |
