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Embedded Linux Primer: A Practical, Real-World ApproachBecause of the nature of Flash memory technology, it is inherently less efficient and more prone to data corruption caused by power loss from much larger write times. The inefficiency stems from the block size. Block sizes of Flash memory devices are often measured in the tens or hundreds of kilobytes. Flash memory can be erased only a block at a time, although writes can usually be executed 1 byte or word at a time. To update a single file, an entire block must be erased and rewritten. It is well known that the distribution of file sizes on any given Linux machine (or other OS) contains many more smaller files than larger files. The histogram in Figure 9-2, generated with gnuplot, illustrates the distribution of file sizes on a typical Linux development system. Figure 9-2. File sizes in bytes From Figure 9-2, we can see that the bulk of the file sizes are well below approximately 10KB. The spike at 4096 represents directories. Directory entries (also files themselves) are exactly 4096 bytes in length, and there are many of them ...» | Код для вставки книги в блог HTML
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