Compacting

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compaction
1. Any of a number of methods to reduce unused or unusable space in primary, secondary, or other memory. See memory compaction.

2. Removal of redundant data from a record. Many systems work with fixed-length records as a convenient method of handling files. This has the disadvantage that all records must be capable of holding the longest record, giving uneconomic use of storage. The fixed-length records can be processed (compacted) into a variable-length form. One method involves the removal of trailing spaces; another involves the replacement of long strings of identical characters by a flag that indicates the occurrence of such a string, together with a count of the number of characters and a single instance of the character. Compaction will require CPU time when the record is stored and again when it is unpacked to fixed-length form, but the consequent saving in storage may justify this.

3. See data compaction.

compaction Physical process that reflects the increase in pressures brought upon sediments as a result of deeper and deeper burial. The individual grains or particles of the sediment are packed closer and closer together, thus reducing pore space. Pore waters are forced out and ultimately compaction will result in grain-to-grain suturing. See also PRESSURE SOLUTION.

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