Microsoft Windows File Systems
Jon Bartholf
POS421: Windows Server Networking
December 13, 2010
Ali Shokraee
TABLE OF CONTENTS

INTRODUCTION..................................................................................................................... 3

FILE AND FILE SYSTEM: WHAT THEY ARE.................................................................. 3

FILE ALLOCATION TABLE (FAT)...................................................................................... 4 FAT12 (12-bit)....................................................................................................................... 4 FAT16 (16-bit)....................................................................................................................... 4 FAT32 (32-bit)....................................................................................................................... 5

HIGH PERFORMANCE FILE SYSTEM (HPFS)................................................................ 5

NEW TECHNOLOGY FILE SYSTEM (NTFS).................................................................... 5

CONCLUSION.......................................................................................................................... 6

APPENDIXES............................................................................................................................ 7 Appendix A: File Allocation Table (FAT) Bit and Usage (Figure 1).................................... 7 Appendix B: FAT and NTFS File System Comparison (Figure 2)........................................ 8

REFERENCES.......................................................................................................................... 9
Microsoft Windows File Systems The management and organization of information is vital to the success of any corporation. This success is determined by the type and number of file systems used in the protection and maintenance of that information. Without a solid file system in place, sensitive data can be lost, stolen, deleted, or infected, which could lead to a significant monetary deficit or the eventual demise of the company. The purpose of this paper is to examine the various file systems incorporated into Microsoft Windows (Windows) operating systems (OS) that not only manages and organizes crucial data, but protects it as well.
File and File System: What They Are A file is any piece of information, such as a song track or an e-mail. Files can be large or small in size and are usually contained within a folder. A file system on the other hand, is the most noticeable part of the OS as it supplies the method for storage and admission to both data and programs within the OS. All file systems have three things in common that they must do: 1. Ensure that the files contained within it are stored safely and do not get overwritten 2. Allow the OS to inscribe new files of data to the storage disk 3. Make the stored files easy to locate and retrieve Current file systems in use by Windows programs basically consist of three main types; however, there are a few more which are not discussed in this paper. The three main Windows file systems are: File Allocation Table (FAT), High Performance File System (HPFS), and New Technology File System (NTFS). The FAT file system is actually broken up into three additional file types, identified as FAT12, FAT16, and FAT32, whereby the numerical value (12, 16, and 32) depicts the size in bits of the FAT cluster.
File Allocation Table (FAT) The File Allocation Table (FAT) was introduced in 1981 with the MS-DOS OS and is now considered prehistoric in terms of the other file systems in use today. “Because of its age, most operating systems, including Microsoft Windows NT®, Windows 98, the Macintosh OS, and some versions of UNIX, offer support for FAT” (Posey, 1999, p. 1). The FAT volume protects itself by creating two copies of the FAT in the event that one is harmed, destroyed, or erased. Formatting a disk with FAT allocates in clusters, in which the size is decided upon by the size of the volume. As files are created, a directory entry is made and the first cluster number in which data is contained is formed. Furthermore, the FAT directory structure does not contain a specific organization format, so files are placed in the first available open location on the drive. FAT uses the 8.3 naming principle, which means that no more than eight characters are allowed before the period and no more than three after the period. All filenames must also be created with the American Standard Code for Information Interchange (ASCII) character set and must start with a letter or number that does not contain spaces (Robb, n.d.). Appendix A illustrates the number of bits used for each of the three FAT types and their major uses.
FAT12 (12-bit) FAT12 is the earliest version of FAT and allows up to 4096 clusters in a partition. Because FAT12 supports cluster sectors from one to sixteen, the maximum size of the partition is 32 megabytes (MB). Windows 2000 uses FAT12 for 16MB or smaller partitions and floppy disks.
FAT16 (16-bit) FAT16 is the successor to FAT12 and is recognized for increasing the limit on disk size from 32MB to 64MB. This was accomplished by raising the cluster number from 12 to 16- bits, thereby enlarging the total number of clusters from 4096 to 65,536. FAT16 is supported by all Windows OS’s, as well as a majority of non-Microsoft OS’s, such as UNIX.
FAT32 (32-bit) The last FAT type is FAT32, which followed FAT16. FAT32 addresses the need for larger storage capacities and was first introduced with Windows 95 OSR2. Most of the newer Windows OS’s support FAT32; however, Windows Server 2000 (Server and Professional editions), Windows Server 2003, and Windows XP (Home and Professional editions) cannot configure a size larger than 32MB using the FAT32 file system (Angelo, 1998). As with previous FAT types, FAT32 uses 32 bits to assign a cluster with the last four bits being reserved. This means that a volume can contain up to 270 million clusters; transforming into a volume of eight terabytes (TB) comprised of 32 kilobytes (KB) clusters.
High Performance File System (HPFS) Because of the increasing challenges that were being placed on network servers, a new file system was necessary that would lengthen the security, organization, and naming system for those networks. The result was the High Performance File System (HPFS). HPFS maintains the directory organization of FAT, but also includes automatic sorting of directory based filenames. These filenames are increased up to 254 double-byte characters and allow a file to be made up of data and attributes that permit flexibility for security and other naming principles (Microsoft Corporation, 2007). Directory entries hold more information under HPFS than under FAT. This includes not only the attribute file, but also information regarding creation, modification, and access. Instead of directing attention to the first cluster in a file, HPFS directory entries are directed to the FNODE, which contains the file’s data.
New Technology File System (NTFS) The New Technology File System (NTFS) was specifically designed for the Windows NT OS and as a replacement for HPFS; however, it also supports the Windows 2000 and Windows XP OS’s. The main difference of FAT and HPFS from NTFS is that there is no reliance on hardware and no special objects are contained within. NTFS is a log-based file system that offers increased security, file-to-file compression, and encryption. The NTFS partition is divided into four sections: Master File Table (MFT), Partition Boot Sector, File System Data, and a MFT backup. The MFT is made up of a 31, 1 kilobyte (KB) records – one for each file in the partition. The first 16 are NTFS system files, with record 0 being the MFT itself. Records 17 through 27 comprise of system recovery change logs, volume and index information, and a cluster allocation information bitmap. Records 28 through 31 are not used and instead have been reserved for future use. The Partition Boot Sector consists of two sections; BIOS perimeter block and a boot code that enables the loading of the NT, Windows 2000, and XP OS’s. The BIOS perimeter block contains information on the volume and file system structure layout, which is similar to the layout in FAT. Appendix B shows the comparison of features for the FAT and NTFS file systems, while Appendix C displays the advantages and disadvantages between the FAT, HPFS, and NTFS files systems.
Conclusion
Each of the file systems discussed above are important to all Windows OS’s, as each one breathes life into the file system structure of one or more specific OS. It is evident that many changes have occurred from the FAT files system of the 1980’s to the newer NTFS files system, but all three are still in use by various OS’s in the Windows and non-Windows families. Only time will tell when all three will eventually be replaced by more capable and technologically advanced file systems in the future.
APPENDIX A
Figure 1: File Allocation Table (FAT) Bit and Usage
[pic]

Figure 1: File Allocation Table (FAT) bit and usage chart. Table recreated from Microsoft Corporations WinHEC version (2004).
APPENDIX B

Figure 2: FAT and NTFS File System Comparison
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Figure 2: File system comparison between FAT and NTFS. Table recreated December 09, 2010, from Microsoft Corporations WinHEC version (2004).
References

Angelo, M. (1998). Windows XP Resource Kit: Working with File Systems. Retrieved December 09, 2010, from http://mozillaquest.com/aboutcomputers/FATData1.html.
Microsoft Corporation (2007). Overview of FAT, HPFS, and NTFS File Systems. Retrieved December 12, 2010, from http://support.microsoft.com/kb/100108.
Microsoft Corporation (2004). WinHEC Version. Local File Systems for Windows. Retrieved December 11, 2010, from http://download.microsoft.com/download/5/b/5/.../LocFileSys.doc.
Posey, B. (2007). Choosing Between File Systems. Microsoft TechNet. Retrieved December 10, from http://technet.microsoft.com/en-us/library/cc750354(printer).aspx.
Robb, D. (n.d.). Windows File Systems. Retrieved December 12, 2010, from http://www. auerbach-publications.com/dynamic_data/2770_1640_Windows%20File%20Systems.htm.