Performance Degradation when Accessing Large Subdirectories (39535)
The information in this article applies to:
• Microsoft MS-DOS operating system 2.11
• Microsoft MS-DOS operating system 3.1
• Microsoft MS-DOS operating system 3.2
• Microsoft MS-DOS operating system 3.21
• Microsoft MS-DOS operating system 3.3
• Microsoft MS-DOS operating system 3.3a
• Microsoft MS-DOS operating system 4.0
• Microsoft MS-DOS operating system 4.01
• Microsoft MS-DOS operating system 5.0
• Microsoft MS-DOS operating system 5.0a
• Microsoft MS-DOS operating system 6.0
• Microsoft MS-DOS operating system 6.2
• Microsoft MS-DOS operating system 6.21
• Microsoft MS-DOS operating system 6.22
This article was previously published under Q39535
SUMMARY
You may notice a performance slowdown for MS-DOS when creating many files
in a subdirectory. MS-DOS is much slower at accessing a subdirectory that
contains many files or deleted files than at accessing a new subdirectory
(that is, a subdirectory containing no deleted files).
This slowdown occurs because MS-DOS directories do not get smaller when you
delete a file. MS-DOS inserts a "no file here" mark for each deleted file
in a directory. There are two different "No file here" marks in the first
bytes of directories:
Value Description
-----------------------------------------------------------------
E5H No file at this location
05H No file at this location
00H No file at this location and no files after this location
Whenever you create a file, MS-DOS searches to the end of the directory to
see if a file with that name already exists. Even if files have been
deleted from the directory, MS-DOS must still check for the "No file here"
entry for each deleted file.
Modification Type: |
Major |
Last Reviewed: |
5/10/2003 |
Keywords: |
KB39535 |
|