If u have NTFS drives then these scandisks will take place rarely only in case of a disk error
*www.auditmypc.com/acronym/NTFS.asp
NTFS is the Windows NT file system. Unlike FAT, NTFS does not use an allocation table but stores information about any file directly with the file. Other operating systems, including Windows 95, and many applications, such as ScanDisk, cannot read NTFS partitions. However, NTFS files or folders that are shared on a network can be accessed by other operating systems. Advantages of NTFS over FAT include faster access to files, more efficient information storage (for example, through a smaller cluster size), better data recovery, integrated file compression, larger disk partitions, and better file security. NTFS is preferred for Windows NT Server because of its better security and fault tolerance features. NTFS partitions also remain relatively unfragmented for long periods of time. A more detailed definition can be found here.
Also if u read the NTFS feature of winxp help, it says that there will be a less chance of using scandisk thnx to new filesystem capablities by using some minidump or something...
Here :
If your volume is formatted as NTFS, Windows automatically logs all file transactions, replaces bad clusters, and stores copies of key information for all files on the NTFS volume.