FAT File System	High PerformanceFile System
Maximum filename length	11(in 8.3 format)	254
Number of dot (.) delimeters allowed	One	Multiple
File Attributes	Bit flags	Bit flags plus up to 64Kb of free-form ASCll of binary information
Maximium Path Length	64	260
Miniumum disk space overhead per file	 Directory entry  (32 bytes)	Directory entry (length varies) + Fnode (512 bytes)
Average wasted space per file	1/2 cluster (typically 2Kb or more)	1/2 sector (256 bytes)
Minimum alocation unit 	Cluster (typically 4Kb or more)	Sector (512 bytes)
Allocation info for files	Centralized in FAT on home track	Located nearby each file in its Fnode
Free disk space info	Centralized in FAT on home track	Located near free space in bitmaps
Free disk space described per byte	2Kb ( 1/2 cluster at 8 sectors /clustor)	4Kb (8 sectors)
Directory structure	Unsorted linear list, must be searched exhaustivily	Sorted B-Tree
Directory Location	Root directory on home track, others scattered	Localized near seek center of volume
Cache replacement strategy	Simple LRU	Modified LRU, sensitive to data type and usage history
Read ahead	None in MS-DOS 3.3 or earlier, primitive read-ahead optional in MS-DOS 4	Always present, sensitive to data type and usage history
Write behind	Not available	Used by default, but can be defeated on per-handle basis