摘要 |
A multilevel data storage system that comprises an interface, an upper-level storage device, a lower-level storage device and first and second compression state modifying engines. Data are transferred through the interface in a first compression state. Data are stored in the upper-level storage device in a second compression state that is higher than the first compression state. Data are stored in the lower-level storage device in a third compression state that is lower than the second compression state. The first compression state modifying engine is located between the interface and the upper-level storage device. The second compression state modifying engine is located between the upper-level storage device and the lower-level storage device.
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