File Systems used by Windows

by : Max Weber



While installing operation system, formatting or installing new hard drive user can define which file system he wants to use. Nowadays FAT works properly under all Windows and MS-DOS, FAT32 works with all Windows after version 95 OSR2, while NTFS is available only under Windows NT (with Service Pack 4), 2000 and XP . Each file system has its own advantages and disadvantages. In order to choose the most suitable file system it is important to understand the differences between them.

FAT is a contracted form for file allocation table[i]. At first it was used by MS-DOS. The structure of FAT volume can be described in the following way: Partition Boot Sector à FAT à copy of FAT à Root Folder à Other folders and files. Copy of FAT is used to protect data from being damaged. The minimum disk size for this file system is 1.4 megabytes (just like the floppy disk), maximum disk size is 4 gigabytes, and limitation on file size is 2 gigabytes. FAT volume can be easily converted to NTFS, but there always exists the possibility of loosing some data and thus it is better to make a back up data before converting. Also the root directory and system files must be stored in a fixed location in order to start operation system properly. Cluster size is determined depending on volume size, maximum clusters number is 65,535. After each operation of writing on the disk FAT must be updated and after that disk read heads must be positioned to the zero track - it consumes our invaluable time for nothing! Access to FAT volume can be granted for anybody – I mean that it can not be locked. FAT has a limitation on the length of the file name – 8 symbols for the name plus 3 for the extension, but in extended mode it is up to 255 symbols.

FAT32 is a newer version of FAT it allows to use more capacious hard drives and it has more efficient space allocation because of smaller cluster size. The structure of FAT32 volume is almost the same as on usual FAT volume. The minimum disk size for this file system is 512 megabytes[ii], maximum disk size is 2 terabytes, and limitation on file size is 4 gigabytes. But FAT32 has an exception – under Windows XP maximum disk capacity is 32 gigabytes. FAT 32 can be converted to NTFS and as in the case of FAT converting to NTFS it is better to make a backup copy of your data. Maximum clusters number is 268,435,456. The length of the file name can be up to 255. FAT 32 does not have built-in security and is hard to recover after system failures.

NTFS is a contracted form for network file system[iii]. The structure of NTFS volume can be described in the following way: Partition Boot Sector à Master File Table (MFT) à System Files à File Area.  MFT contains information about all the files and folders on the volume. The minimum disk size for this file system is 10 megabytes, maximum disk size is much than 2 terabytes, and maximum file size is limited only by the capacity of the volume which contains that file. Unfortunately some programs can not work properly with NTFS and thus it is important to check this nuance before choosing this file system. NTFS can not be converted to FAT or FAT32 and the only way to do this is to format this volume once again. Maximum clusters number is nearly unlimited. The length of the file name can be up to 255. The most important innovations and advantages of NTFS over FAT and FAT32 are the following: alternate streams, compression, support of Unicode symbols, object permissions, built-in security, high recoverability and domain support[iv]. In other words NTFS is more reliable and has many useful innovations. After system failures it is very easy to recover it, but there is an exception – if either the master boot record or the boot sector is corrupted you might not get access to the data on that volume. NTFS also can perform cluster remapping – it is useful if there are bad sectors on your drive. This procedure can be described in the following way: after detection of bad sector NTFS dynamically remaps the cluster with the bad sector and allocates a new cluster for the data, but this operation is applicable only for writing operations. NTFS can easily limit access to the data by using permissions. It is almost impossible to get access to such data without corresponding permission because NTFS uses 32bit key sequence to access that data.  

Moreover Windows 2000 support more advanced file system – NTFS5[v]. It has much more advantages even over usual NTFS: encryption (even if somebody would get access to the encrypted data he could not read it), disk quotas (system administrators can limit disk space usage), reparse points, mounted volumes, sparse files, distributed link tracking and some other. 

To summarize my overview I want to emphasize the most important advantages and disadvantages of each file system and make some recommendations about them: 1) FAT can be used with very old computers and with small hard drives (under 200 megabytes). Recovering data from FAT volumes is problematic, space allocation is ineffective, and security level is very law. I think FAT is just a remnant of antiquity. 2) FAT 32 is relatively good file system although it has some significant disadvantages. It can be used with not very large hard drives. FAT32 uses hard disk effectively enough. 3) NTFS is the most advanced file system which has more advantages than disadvantages. It can be used with large hard drives most effectively although lack of compatibility with old Windows versions. NTFS uses the most advanced methods of reading and writing data.

From my own experience I can recommend to use both NTFS and FAT32 file systems on your home PC – NTFS for system volume and FAT 32 for other data. Of course for public computers it is more preferable NTFS in order for data safety and security. I did not see significant differences in the speed while working with NTFS and FAT32Free Articles, but stability and recoverability of NTFS is worthy of best commendations.

[i] Microsoft Windows XP Help

[ii] Msdn.Microsoft.com

[iii] www.ntfs.com

[iv] www.ntfs.com

[v] www.willhawkins.com