Comparing and Contrasting File Systems used by Windows - Assignment Example

Running Head: File Systems used by Windows Comparing and Contrasting File Systems used by Windows (Style: APA) ID 19714 Order No. 251599 12 November 2008 Abstract A file System is based on "cluster of sectors" which is the smallest unit on a Hard Disk that an operating system can manage. A file that is saved on the hard disk comprises of a number of clusters and hence its characteristics depend upon the file system that has been chosen by the operating system. The number of clusters that a file system can support depends upon the age of the file system in the industry. The first ever file system used on a Microsoft operating system (MS DOS) is the FAT 16 (File Allocation table with 16 bit entries) file system. The modern Microsoft Windows platforms (XP, Vista, and Windows 2000/2003) support FAT 16 (File Allocation table with 16 bit entries), FAT 32 (File Allocation table with 32 bit entries), NTFS (New Technology File System), EFS (Encryption File System), CDFS (Compact Disk File System - used by CDs), and UDF (Universal Disk Formats - used by DVDs). This paper presents a comparison between the key file systems used by Windows Operating System - FAT16, FAT32 & NTFS and also provides a brief introduction on Encrypted File System. Table of Contents: Introduction: The File system in Windows can be selected at the time of installation of the Operating System, or at the time of creating a logical volume within a single physical hard disk or an array of hard disks using RAID 0, RAID 1 or RAID 5. Windows allows a very simple method to convert the file system of a logical volume from FAT 16 to FAT 32 or from FAT 32 to NTFS without taking down the server or loss of data. However, Windows doesn't allow a backward conversion from NTFS to FAT 32 or from FAT 32 to FAT 16. For a backward conversion, the disk needs to be formatted and volumes created again. The characteristics of a file managed by the Operating System in terms of size limitations & security depend upon the file system chosen. The File Allocation Table (FAT) actually is a registry of hexadecimal values that identify the location of clusters within a logical partition. This helps the operating system to locate all the clusters constituting a file. This process is important because all clusters constituting a file are not stored at one place but are distributed across the entire Hard Disk Storage (a process called Fragmentation). The OS maintains two File Allocation Tables within a cluster such that if one is corrupted, the second can be used. The FAT assigns a hexadecimal address FFF7 to a bad cluster (due to surface or magnetic errors) such that the OS is able to recognize them while collating clusters to access a file. FAT16 has some distinct disadvantages that are addressed by FAT32 and FAT32 in turn have some distinct disadvantages covered by NTFS. The following section presents the differences among the three primary file systems and introduction to the other file systems that are supported by Windows XP, Windows Vista and Windows 2000/2003. File Systems supported by Windows XP and Windows 2000/2003: The FAT16 in earlier versions of MS DOS used to be 2 GB of logical partition (Volume) size but with the introduction of NT by Microsoft enabled it to support 4 GB of Logical partition (Volume) size. It has two primary limitations - length of file name and size of clusters in a 2GB/4GB partition. FAT16 supports a file size of only eight characters with three extension characters. No spaces in between characters were allowed. Moreover, the minimum cluster size in a 2GB/4GB partition is 32 KB. This lead to lot of wastage of disk space because file sizes of a few KBs used to block 32 KB clusters (A cluster cannot be shared; it is always dedicated to a file). THE FAT16 file system supported limited entries in the boot file and limited number of files per directory. These limitations of FAT16 were eliminated by Microsoft by introducing Virtual FAT (VFAT) which was later on enhanced to form FAT32. FAT32 supports 255 characters in a filename whereby spaces were allowed in between characters. The special characters " / [ ] : ; | = , ^ * are not allowed to be included in the file names in either of the file systems. FAT32 can theoretically support up to 8 Terabytes of size of Partition (Logical Volume). However, Microsoft limited the size to 32 GB to promote NTFS. A 4GB partition in FAT32 can support cluster sizes of 4 KB thus ensuring better utilization of disk space by smaller files. The maximum partition size of 32 GB supported in Windows (enforced by Microsoft as a practical limit) requires cluster sizes of 16 KB. Microsoft however enhanced this enforced limit of 32 GB to 2 Terabytes in versions beyond Windows 2000. FAT32 File system supports unlimited entries in boot file and unlimited files per folder. [http://en.kioskea.net/repar/fat32.php3; http://oldfiles.org.uk/powerload/drives.htm; http://www.comptechdoc.org/os/windows/win2k/win2kfiles.html; Microsoft Help and Support, Article ID: 154997. Rev3.1, 2007] FAT32 has more robust fault tolerance compared with FAT16. FAT32 can relocate the root folder anywhere within the storage. The boot record is enhanced to include backup of critical data structures. In FAT16, the duplicate copy of the File Allocation Table is mirrored and thus can be used only if the primary copy is corrupted. However, in FAT32, the duplicate copy can be made primary whereby the primary one can be switched to mirrored mode dynamically. Microsoft tried their best to make FAT32 as backward compatible. However, a number of system level programs of FAT16 do not work on FAT32. [Microsoft Help and Support, Article ID: 154997. Rev3.1, 2007] With growing user needs from the Operating System, the limitations of FAT32 started posing problems. The maximum file size supported by FAT32 is 4GB - one byte. Thus files larger than 4GB could not be supported on a FAT32 partition. Examples are Oracle, Microsoft SQL Server LDF & MDB, Exchange EDB, Outlook PST, etc. database files. The cluster size of FAT32 cannot be extended or reduced once allocated within a partition. Moreover, the partition itself cannot be formatted for sizes beyond 32 GB using FAT32 based formatting tools. The biggest limitation of FAT32 is security. It offers NIL security for files & folders stored locally. The only security possible is at share level over a network. [Microsoft Help and Support, Article ID: 314463. Rev1.4, 2007] These limitations of FAT32 were solved by Microsoft in the NTFS (New Technology File System) File System. NTFS supports 255 characters of filenames just like FAT32. In both file systems, the filenames preserve case. NTFS support compression of files for cluster sizes of 4KB but doesn't support compression for larger cluster sizes. Hence, large databases that are no longer in use can be compressed and archived. Using compressed files reduces I/O operations but increases CPU utilization. NTFS has many advanced features. Some of the most prominent ones are: File Journaling: NTFS maintains a copy of every file within the volume Supports advanced local security at file/folder level Provides automatic disk corruption checking & correction at every transaction Supports file/folder level auditing Supports advanced file recovery features Maintains a master file table to save individual file, boot sector, disk structure and file recovery information Theoretically supports a maximum partition size of 16 exabytes [1 Exabytes = 1024 Petabytes; 1 Petabyte = 1024 Terabytes; 1 Terabyte = 1024 Gigabytes]. However, Practically Microsoft has applied a limit of 2TB for Single Disk/Mirrored Volumes and up to 62 TB for RAID-5 volumes. Supports POSIX (Portable Operating System Interface for UNIX) Reduced fragmentation thus faster file access speeds Supports file encryption using Encrypted File System Supports disk quota allocation per user on a shared network drive [Nichol, Alex. 2002, available at http://www.aumha.org/win5/a/ntfs.php; http://technet.microsoft.com/en-us/library/cc773268.aspx; http://www.comptechdoc.org/os/windows/win2k/win2kfiles.html] In addition to FAT16, FAT32 and NTFS, Windows XP, Windows Vista and Windows 2000/2003 also support Compact Disk File System for CDs, Encryption File System and Universal Disk Formats for DVDs. The CDFS has the following rules: The directory & file names on a compact disk must have fewer than 32 characters. The directory & file names must be in capital letters. The directory tree in a Compact Disk cannot exceed 8 levels from the root. File name extensions on a compact disk are not mandatory. [http://www.microsoft.com/technet/prodtechnol/windows2000serv/reskit/core/fncc_fil_qocq.mspxmfr=true] Universal disk format is a standard file system developed by OSTA. It is compatible with all the common file system formats and can be used in a variety of devices like CD-ROM, CD-R, CD-RW, DVD-R, DVD+R, DVD-RW, DVD+RW, Camera Chips, etc. [http://homepage.mac.com/wenguangwang/myhome/udf.html] Encryption File System: Windows XP Standard & Professional, Windows Vista (all versions), Windows 2000 (all versions) and Windows 2003 (all versions) support file level encryption using the Encrypted File System (EFS). The programs need to have the decryption codes to open the encrypted files. The encryption keys are generated and managed through Windows Certificate Services. The encryption happens at the file system level and not the application level. Hence, if proper decrypting keys are installed, the applications are able to seamlessly open & modify files without any delays of glitches. The user should however manage the keys very carefully. Losing decrypting keys means losing data altogether. The file encryption keys can be exported and stored outside the computer in distributed media (CDs/DVDs, etc.). The encryption algorithms used by Windows are 3DES (Triple Digital Encryption Standard) and AES (Advanced Digital Encryption Standard). [Bragg, Roberta. 2008. http://technet.microsoft.com/en-us/library/cc700811(printer).aspx] Conclusion: Microsoft has been very innovative in creating new file system technologies in order to cater to the user needs. FAT16 was the original file system created by Microsoft on Windows platform which was enhanced considerably in FAT32. FAT32 served for much larger capacities and access speeds but lacked advanced resilience and security features. All limitations of FAT32 were considerably solved in the NTFS file system which is the de facto standard of the modern Windows platform. NTFS offers much advanced security and fault tolerance features. Encryption File System is an internal feature of NTFS that enabled high level security of files on a computer by using advanced encryption algorithms - 3DES and AES. The additional file systems that Microsoft supports are CDFS and UDF that are used by the various optical disk formats. Reference List: Bragg, Roberta. (2008). The Encrypting File System. Microsoft Technet. Retrieved on 12 November 2008. Available at http://technet.microsoft.com/en-us/library/cc700811(printer).aspx Description of the FAT32 File System. (2007). Article ID: 154997. Rev3.1. Microsoft Help and Support . Retrieved on 12 November 2008. Available at http://support.microsoft.com/kb/154997. Limitations of the FAT32 File System in Windows XP. (2007). Article ID: 314463. Rev1.4. Microsoft Help and Support. Retrieved on 12 November 2008. Available at http://support.microsoft.com/kb/314463 11/. Nichol, Alex. (2002). FAT and NTFS File System in Windows XP. Retrieved on 12 November 2008. Available at http://www.aumha.org/win5/a/ntfs.php. Purdue University On-Line Writing Lab (OWL) (2008), APA Formatting and Style Guide, Retrieved 12 November, 2008, from http://owl.english.purdue.edu/owl/resource/560/01/ Windows 2000 File Systems. Retrieved on 12 November 2008. Available at http://www.comptechdoc.org/os/windows/win2k/win2kfiles.html In addition to the cited references, I would like to extend my special thanks to all those who extended to me knowledge and information that helped me to put together this paper. On their request, their names have not been published herewith. End of Document Read More