Abstract:
The subject disclosure is directed towards predicting compressibility of a data block, and using the predicted compressibility in determining whether a data block if compressed will be sufficiently compressible to justify compression. In one aspect, data of the data block is processed to obtain an entropy estimate of the data block, e.g., based upon distinct value estimation. The compressibility prediction may be used in conjunction with a chunking mechanism of a data deduplication system.
Abstract:
A memory region can durably self-identify as being faulty when read. Information that would have been assigned to the faulty memory region can be assigned to another of that sized region in memory using a replacement encoding technique. For phase change memory, at least two fault states can be provided for durably self-identifying a faulty memory region; one state at a highest resistance range and the other state at a lowest resistance range. Replacement cells can be used to shift or assign data when a self-identifying memory fault is present. A memory controller and memory module, alone or in combination may manage replacement cell use and facilitate driving a newly discovered faulty cell to a fault state if the faulty cell is not already at the fault state.