[Vadikan]

Alex Cop

пришёл к выводу, что на практике нет смысла ставить внешнее ПО для дефрагментации

Я тоже давно к такому выводу пришел Несколько раз под напором хороших сетевых знакомых соглашался поставить какой-нибудь лидер рынка дефрагментации, но каждый раз сносил за ненадобностью. Более того, ХР сама проводит дефрагментацию необходимых файлов, если не отключать prefetch.

How does this scheme provide a performance benefit? The answer lies in the fact that during typical system boot or application startup, the order of faults is such that some pages are brought in from one part of a file, then from another part of the same file, then pages are read from a different file, then perhaps from a directory, and so on. This jumping around results in moving the heads around on the disk. Microsoft has learned through analysis that this slows boot and application startup times. By prefetching data from a file or directory all at once before accessing another one, this scattered seeking for data on the disk is greatly reduced or eliminated, thus improving the overall time for system and application startup. To minimize seeking even further, every three days or so, during system idle periods, the Task Scheduler organizes a list of files and directories in the order that they are referenced during a boot or application start, and stores the list in a file named \Windows\Prefech\Layout.ini. Figure 1 shows the contents of a prefetch directory, highlighting the layout file. Then it launches the system defragmenter with a command-line option that tells the defragmenter to defragment based on the contents of the file instead of performing a full defrag. The defragmenter finds a contiguous area on each volume large enough to hold all the listed files and directories that reside on that volume and then moves them in their entirety into that area so that they are stored one after the other. Thus, future prefetch operations will even be more efficient because all the data to be read in is now stored physically on the disk in the order it will be read. Since the number of files defragmented for prefetching is usually only in the hundreds, this defragmentation is much faster than full defragmentations.

(см. раздел Prefetch). Сорри, цитату переводить нет времени