| 摘要 |
PURPOSE:To reduce the overhead for security and release of a data area that is caused by the production and deletion of a member, by using an idle logic track control table, a logic track allocating means and a logic track releasing means. CONSTITUTION:When a member is produced, a logic track allocating means 7 is called out to secure a data storing area. The means 7 checks whether an idle logic track is registered or not to an idle logic track control table 9. Then the idle logic track of registered is allocated. While the idle logic track is registered to the table 9 if not idle logic track is registered to the table 9. When the member is deleted, a logic track releasing means 8 is called out. The means 8 traces a chain set between blocks and at the same time sends all logic tracks occupied by the member back to the table 9. When the table 9 is filled, those logic tracks are sent back directly to a bit map 3 for using states of direct logic tracks.
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