| 摘要 |
The inventive state mechanism assigns N+1 tags to N versions of an object stored in N memory areas. Thus, one tag is unused. An additional tag is used as a null or uninitialized tag. The other tags are assigned in a particular precedence order to revisions as they are stored. Thus, each assigned tag, except the null tag, has both a unique predecessor as well as a unique successor tag. The last tag of the sequence is lower in precedence to the first tag of the sequence, and this forms the cyclic relationship. The unused tag is used to determine the tag that is to be assigned to the next revision. The unused tag is also used to determine which revision is the most current revision. The inventive state mechanism is used by a memory management controller in maintaining the revisions.
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