Several file systems for Windows operating systems

Source: Internet
Author: User
Tags file system disk defragmenter

windows3.x and MS-DOS have been using the file allocation table (FAT) system; Windows95 is using the extended FAT file system; The WindowsNT file system also supports two 32-bit file system--windowsnt file System (NTFS) and High-performance file Systems (HPFS) while continuing to support 16-bit file systems. These file systems have their advantages and disadvantages and are suitable for different application purposes.

file allocation table (FAT) system

The FAT file system began to be applied to MS-dos in 1982. The main advantage of the FAT file system is that it can be accessed by a variety of operating systems, such as MS-DOS, windows3.x, windows95/98/2k, WindowsNT, and OS/2. And for an arc-compatible computer, its primary partition must be formatted as a FAT partition, which can only be stored as a boot machine file, not for storing data and other application files. Unfortunately, the FAT file does not support long file names. People name the file by 8 character name 3 characters extension 8.3 naming rule limit. At the same time, the FAT file system cannot support the advanced fault-tolerant characteristics of the system, and has no internal security characteristics.

Ii. Extended file allocation table (VFAT) system

In Windows95, the long file name problem is solved by extending the FAT file system, which is what people call an extended fat (VFAT) file system. In Windows95, filenames can be up to 255 characters long, so it's easy to use names to represent files. However, in order to be compatible with MS-DOS and WIN16-bit programs, it still retains an extension. It also supports file date and time attributes, keeping the file creation date/time for each file, the date/time when the file was recently modified, and the date/time the file was recently opened. Three date/time stamps. Long file names are supported by Windows95 's VFAT file system and the WindowsNT file System (NTFS) and High-performance file systems that are mentioned below. The following points are noted when using this feature:

1. Because long file names occupy multiple directory entries, if you create a filename file in the root directory, it affects the total number of files that can be stored in the root directory, and if you create a long file name file in a subdirectory, you will take up some more disk space.

2. Delete one or change a file name converted from a long file name in MS-DOS the name-character directory entries that are used to hold long filenames and the type information entries that hold long file names are lost in their long file names, which will be permanently unusable under general MS-DOS if they are not handled in a special way.

3. Some existing DOS-based disk management utilities, such as Disk Defragmenter, disk-bit editor, and some disk backup software, can break long file name entries for FAT tables when processing fat table entries, but the corresponding 8.3 file names are unaffected. As a result, we should use the Disk Management utility provided by WINDOWS95 to perform file backup, recovery, and so on to preserve long filenames.

4. Some applications running in MS-DOS and windows3.x, because it does not recognize long filenames, use these applications to open files with long filenames and then store them, and long file names are lost. Or you can copy a file with a long file name to a system that does not support long file names, and the long file name will also be lost.

Third, WindowsNT file system

NTFS supports all the benefits of windowsnt. The most important of these advantages is the WindowsNT security. Combined with the NTFS file system, you can specify who can access a file or directory and what to do with it. When you create a file, you can notify WindowsNT which users can read the file and which users can modify it, and also specify who can list the contents of a directory and who can add files to the directory. Even if the user knows the path to the file, you can still prevent access to the files in the directory, and only files in the NTFS partition have this ability called arbitrary access control.

The second advantage of NTFS is that it has advanced fault-tolerant capabilities. NTFS uses a technology called transaction (transaction) login to track modifications to the disk, so NTFS can recover errors in seconds instead of HPFS minutes or hours (depending on the size of the HPFS partition).

The third advantage of NTFS is that its files are not susceptible to viruses and system crashes, which are directly rooted in the high security performance of the WindowsNT operating system. Even when FAT and NTFS two file systems coexist on one disk, it is difficult for a typical virus to find a living space in the NTFS file system because the NTFS file system can only be windowsnt recognized.

For large partitions, NTFS is more efficient than fat and HPFS, and fat and HPFS require more space than NTFS to store information that the file system uses to manage files and directories on the hard disk.

In addition, because the NTFS file system supports long file names, the file name is not subject to the 8.3 naming rules, so you can give the file a filename that reflects its meaning. NTFS supports backward compatibility, and can even produce old short file names from new long filenames. When a file is written to a removable media (such as a floppy disk), it automatically takes the FAT file name Fat filesystem.

In fact, the main weakness of NTFS is that it can only be identified by WindowsNT. The NTFS file system can access files for the FAT file system and the HPFS file system, but its files cannot be accessed by the FAT file system and the HPFS file system, and the compatibility is not particularly good. However, this restriction is also an advantage from the perspective of network security, which ensures that if other operating systems do not have Windows security control, their users cannot access files in the NTFS partition. Also, if the boot drive (that is, the C drive) uses the NTFS file system, the Flexboot option cannot be used because the DOS system boots only from the C drive, but not from the NTFS drive. Relative to WindowsNT, its boot partition can be FAT, NTFS, and HPFS. Finally, there is a problem with many backup utilities that are still having problems manipulating NTFS partitions even with the WindowsNT driver.

Iv. High-performance file system

OS/2 High Performance File system (HPFS) mainly overcomes the disadvantage that FAT file system is unsuitable for high-end operating system, HPFS supports long file name, and has stronger error correcting ability than FAT file system. WindowsNT also supports HPFS, making the transition from OS/2 to windowsnt easier. HPFS and NTFS have many of the same features, including long filenames, but they are less reliable and lower-performing.

All 4 of these file systems are supported by Windows. In general, users can take into account the file system, file system security mechanism, ease of use and the corresponding hardware environment to consider the need to install the file system, select one of the file systems or their combination of several file systems, so that the system works in the best state.

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