DATA COMPRESSION

1. Increasing the amount of data that can be stored in a given domain , such as space, time , or frequency , or contained in a given message length. 2. Reducing the amount of storage space required to store a given amount of data, or reducing the length of message required to transfer a given amount of information . Note 1: Data compression may be accomplished by simply squeezing a given amount of data into a smaller space, for example, by increasing packing density or by transferring data on punched cards onto magnetic tape . Note 2: Data compression does not reduce the amount of data used to represent a given amount of information, whereas data compaction does. Both data compression and data compaction result in the use of fewer data elements for a given amount of information .