| 摘要 |
<p>PURPOSE:To efficiently utilize a rewritable PROM by counting the number of times of rewriting of the rewritable PROM, and transmitting its data to an unused area in the same PROM, when it approaches the number of times of a service life. CONSTITUTION:Managing information of each data and unused area managing information are stored in a memory managing information area A. When a rewriting event to data 1 is generated, a rewriting service life frequency CMAX of another memory 2 is read, the number of times of rewriting C1 is read and each numerical value is compared. In this state, in the case of C1 CMAX, data 1 managing information of a rewritable PROM 1 reads out unused area manag ing information and whether a data transfer can be executed or not is decided. In this state, in the case of an unuses area (m) >= data 1 length, a transfer of data 1 is executed and '1' is written in a data 1 rewriting frequency counting value. Simultaneously, after updating the data 1 managing information, the data 1 is rewritten, and the number of times of rewriting of the data 1 is updat ed. In such a way, a service life of the rewritable PROM can be extended.</p> |
