The NTFS File System is essentially a huge database that keeps track of all the files on your Windows XP Pro hard disk. When you create a file, or edit and then resave that file, the NTFS creates an entry and records the date in the Created or Modified timestamp so you can access the Properties sheet of the file and check the Created or Modified entries later.
NTFS also creates and keeps track of another timestamp called Accessed. The timestamp lists the date on which the file was last accessed and whether the file was opened and read or changed and saved. Each time NTFS updates a file’s Properties sheet, an accompanying disk read/write operation occurs. Since the Accessed timestamp does not add much useful information, you may consider the read/write operation incurred to record it wasteful.