File systems are an integral part of all operating systems with long-term storage capabilities. There are two different parts of the file system, the system for storing files and the folder structure in which they are organized. In modern operating systems, where several users can access the same files simultaneously, it has also become necessary for such features as access control and different types of file protection.
File is a collection of binary data. A file could represent an application, document or in some cases part of the file system itself. In modern computing it is quite common that they are several different storage devices connected to the same computer. Common data structure like file system allows the computer to access many different storage devices in the same way, for example, when looking at the contents of the hard drive or CDs as you view it through the same interface, although they are completely different from data mapped to them In a completely different way. Files can have a very different data structure within them, but anyone can access the same methods built into the file system. The arrangement of data within the file is then determined by the application creating it. The file systems also store a number of attributes for the files in it.
All files have a name that can be accessed by the user. In most modern file systems, the name consists of three parts, unique name, period and extension. For example, the "bob.jpg" file is uniquely identified with the first word "bob", but the extension jpg indicates that it is a JPEG image file. The file program allows the operating system to decide what to do with the file if someone tries to open it. The operating system holds a list of file companies. If a user tries to access & # 39; bob.jpg & # 39; Then it is likely that it will open in the system as the default image viewer.
The system also stores the location of a file. Some filesystems can only store files as one adjacent block. This has simplified storage and access to the file because the system only needs to know where the file starts on the disk and how big it is. However, it causes complications if the file is extended or removed because there is not enough space to fit the larger version of the file. Most modern file systems overcome this problem by using a linked file format. This allows the files to store in any number of parts. The file system must then be stored as each block of the file is and how big it is. This simply simplifies file assignment but is slower than matching assignment as it is possible for the file to spread throughout the disk. The modern operating system addresses these shortcomings by providing disk content. This is a utility that reorganizes all files on the disk so that they are all in continuous blocks.
File protection information is also integrated into the file system. Protection can range from simple systems implemented in the FAT system to early windows where files could be marked as read-only or hidden in safer systems that are implemented in NTFS, since system administrators can set special read and write privileges for different users or of users. While file protection adds a lot of complexity and potential difficulties, it is necessary in an environment where many different computers or users can access the same drives through a network or a temporary system like raptor.
Some files System also stores data about which user created a file and whenever they created it. While this is not necessary to run the file system, it is useful for system users.
In order for the file system to work correctly, it requires a number of defined functions to create, open, and edit files. Almost all file systems provide the same basic methods for processing files.
File system must be able to create a file. To do this, you must have enough space on the drive to match the file. There must also be no other file in the folder to be placed with the same name. When the file is created, the system will record a list of all the items listed above.
Once a file has been created, we may need to edit it. This may be simply adding some data at the end of it or removing or replacing data already stored within it. When this happens, the system continues to write a cursor mark, as the next typing of the file should occur.
In order for the file to be useful, it must of course be readable. To do this all you need to know the name and path of the file. From this, the file system can make sure where the drive is stored. While reading is reading, the system keeps the reader. This stores which part of the drive is read next.
In some cases, you can not read the entire file in memory. File system also allows you to move the browser to a file. To perform this feature, the system needs to know how far into the file you want to read the cursor to jump. An example of where this would be useful is a database system. When a query is made on the database it is obviously inefficient to read the entire file to the extent that the required data is in place, the application that controls the database would determine where the file is a necessary part of the data and jump to it. This feature is often known as file search.
File system also allows you to delete files. To do this, you need to know the name and path of the file. To delete a file, the system simply removes its entry from the folder structure and adds to the entire space previously used in the free list (or whatever other space management system it uses).
These are essential operations that a file system needs to work properly. They are present in all modern computer systems, but how they work may differ. For example, to perform an deleted file operation in a modern file system like NTFS that has file protection built in it would be more complicated than the same operation in an older file system like FAT. Both systems would first check if the file was in use before continuing. NTFS would then check if the user who is currently deleting the file is authorized to do so. Some filesystems also allow many to open the same file simultaneously, and must decide if users have permission to rewrite files if other users have it open. If two users have read and write permission to register, should you be able to write it while the other is still open? Or if one user has read a written permission and another has read a file, the user should be able to write in writing if there is no risk that another user will try to do that too?
Different File Systems also support different access methods. The simplest method of accessing information in a file is accessible access. This is where information in a file is viewed from the beginning of a single record at a time. To change the status of a file, you can rewind or forward a number of files or reset at the beginning of the file. This access method is based on file storage system for tape drives, but also works on a series of access devices (like morder DAT tape drives) as it is random-access ones (like hard drive). Although this method is very simple in its operation and is most suitable for certain features like playing the media, it is very inefficient for more complex tasks such as data management. A more modern approach that makes it easier for a reading project that is likely to be a non-direct reading is direct access. Direct access allows files to read or overwrite the order in which the application requires. This method of allowing some parts of the file to be read in any order is better suited to modern drives as they also allow some part of the drive to be read in any order with a low drop in the migration process. Direct access is better equipped for most applications than synchronized accessibility as it is designed around the most common storage device in use today, instead of one that is not used much longer except for large offline copies. Depending on how direct access works, you can also build other methods of access to direct access, such as synchronized access, or to create an index of all files from the file rate to speed up finding data in a file.
In addition to storing and managing files on drives, the file system also maintains system directories where the files are referrals. Modern hard disk stores hundreds of gigabytes. The file system helps organize this information by dividing it into folders. Files can contain files or more folders. As files, there are some basic operations that a file system must be able to perform in the folder structure to function properly.
You must be able to create a file. This is also a summary of peration of a file, while also creating the file, it must be added to the file plan.
When a file is deleted, the space required for the file is marked as space. The file itself must also be removed from the folder structure.
Files may need to rename files. This requires a change of folder structure, but the file itself is unchanged.
Directory list. In order to use the disk correctly, the user needs to know what is in all the execution books stored on it. In addition, the user must be able to browse folders on the hard drive.
Since the first file features were designed, they have undergone some major developments. Before folders were recorded on file system, all files were stored at the same level. This is basically a single-folder system with all files stored. Next progress on this would be considered as the first file unit, the bilateral file. In this, Singe is a list of folders that are all on the same level. The files are then stored in these folders. This allows different users and applications to store the files separately. After that, the first installation file came as we know them today, a registered tree. Tree structure directories adds to two-level directories by allowing directories as well as files to be stored in folders. All modern file systems use tree-build directories, but many have more features, such as security based on them.
Protection can be implemented in many ways. Some file systems allow you to have password-protected folders. In this system. The file system will not allow you to open a folder before it is given a username and password for it. Others increase this system by giving other users or groups access privileges. The operating system requires the user to log in before using the computer, restricting their access to areas that do not require permission. The system that a computer science department uses for storage space and study material on raptor is a good example of this. In a file system like NTFS, you can manage all types of storage capacity, network access, and device usage, such as a printer. You can also implement other types of access controls outside the file system. For example, programs like zip work allow you to password protected files.
There are many different file systems that are now available to us on many different platforms and depending on which application and size of the drive there are different conditions suitable for different file systems. If you were designing a backup system backup file system, then a roll-up adjustment would be more appropriate than a direct access method that constraints the hardware. Also, if you have the small hard disk at home, there would be no real advantage of using more complex file systems with features like protection, which is unlikely to be needed. If I were to design a 10 Gigabyte drive file system, I would use a related assignment over adjacent to make effective use of the drive space and limit the time required to maintain the drive. I would also design a direct access method over a series of access to take advantage of the hardware strengths. The file manager would be a tree based on allowing better organization of information on the drive and would allow acyclic directories to facilitate some users to work on the same project. It would also have a file protection system that allowed different access rights for different user groups and password protection on folders and individual files. Any file system already in use the features described above as ideal for 10gig hard drive is now Available are these NTFS for Windows NT and XP operating system and ext2 used in Linux.
Sam Harnett MSc mBCS
Source by Sam Harnett