A New Problem: Misdirected Writes
Explore how operating systems handle the problem of misdirected writes in storage systems. Understand the role of adding physical identifiers to checksums, which helps detect errors when data blocks are written to incorrect disk locations. Learn why redundancy and additional metadata are essential for ensuring data integrity in modern disk and RAID environments.
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The basic scheme described in the previous lesson works well in the general case of corrupted blocks. However, modern disks have a couple of unusual failure modes that require different solutions.
The first failure mode of interest is called a misdirected write. This arises in disk and RAID controllers which write the data to disk correctly, except in the wrong location. In a single-disk system, this means that the disk wrote block not to address (as desired) but ...