Yes, but this is exactly what the option 9 sorting does. Files that are used at exactly the same time, will be placed next to each other during the sorting.
The "-a 9" optimization (sort by last access date) cannot always be used. Vista has the NtfsDisableLastAccessUpdate registry key set on by default, and on other Windows versions the user may have turned it on. And then there are programs such as virus scanners and backup programs that will reset the last access time to "now" for all files on disk.
Secondly, the "-a 9" optimization will sort the last accessed files to the begin of the disk. If a program uses 2 files when it starts up, then the second file will be placed on disk before
the first file. The files are next to each other, as you say, but in reverse order.
So I think that optimization by prefetch scenario data will be a big improvement.
...and what would you do, if a file was shared by several applications?
Good question. The system DLL's are a good example. I haven't thought that far ahead yet, I don't even know the format of the scenario files yet. Perhaps shared files can be placed in a special area before all the other files. Or perhaps they can be placed with the files of the first program that happens to be optimized, and ignored when the optimizer encounters them again in another program. Something like that.