It is not unusual for an active file to be read once from the platter surface (if it is totally sequential) and never require further head access until the computer is shut down. Thus, if the files are not sequential in data clusters, the heads will be guaranteed to move to seek each non-sequential cluster that was not buffered on the read.įurther, smart controllers have a flush-if-not-used stack approach. In practice, the sectors containing the file clusters are buffered *on the first read* into the 16mb+ controller memory, and the controller will request further head reads only at the point when the clusters required are not in the sectors buffered on the controller card. True, reading "some" from file A, then "some" from file B, then "more" from file A moves the head around at the commencement of opening and reading each file.
If Vegas needs bits and pieces of a file, at least the clusters that make up the bits and pieces will be sequential. The easiest disk read is from sequentially-oriented data bits (defragged file). Statement presumes incomplete reads of each file, which would be guaranteed with fragmented files even before Vegas accesses them. "already bouncing the head around as much as fragmentation would" This is why you can *unplug* a drive in middle of a good program's defrag and not lose a byte. Then the map to the data start is modified. Moreover, the data is not just picked up and slapped down somewhere else, but remains in its old location (and in the mapping table) until the new write proves to be dependable. The best defrag programs have 'surface-checkers' that will move your data from areas that require multiple passes in order to read (usually a drive will auto retry on read up to 20 times before reporting a bad cluster) to areas that only require one pass to read.Ģ. ".while you are defragging your data is in danger of being damaged."ġ.
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