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SUMMARYSeveral Long Filename to 8.3 (MS-DOS compatible) name conversion performance enhancements have been introduced in Windows NT Workstation and Windows NT Server version 3.5(and later). These enhancements include a faster worst case scenario algorithm, as well as improved context retention across enumeration calls. Although these changes yield substantial improvements, you should continue to avoid using numerous long, similar names. MORE INFORMATION
In Windows NT version 3.1, worst-case file manipulation of extremely large
directories (500 to several thousand files) with similar long names was
time consuming. This was evident when receiving screen output from a DIR
command or reading a directory in File Manager.
That algorithm had been changed in Windows NT 3.5(and later) for enhanced performance. Since the occurrence of similar 8.3 names is generally minimal, only the first four attempts at generating the 8.3 name work like they did in Windows NT 3.1. The fifth attempt takes the first two characters of the long name, then the next four characters are generated by a hashing function of the entire name, and the last two characters are "~5". Only when the hashing of the middle four characters no longer produces a unique name will the "~5" be incremented to "~6" and so on. For example: Subsequent iterations are performed faster than under Windows NT 3.1. NOTE: By avoiding using long names that are similar in the first 6 characters, enumeration are even more efficient. Additional query words: prodnt lfn long name
Keywords : kbother ntfilesys |
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