In order to understand the principles by which computer systems function, it is not enough just to interact with the "OS" at the visual level. To fully understand everything that is happening, you should clearly understand what a file and file structure are. When considering this topic, it will be indicated why this is needed.
The concept of a file and file structure
First you need to decide on the most important terms and concepts. The key here is the concept of a file, which determines the mechanisms of the system in terms of software.
So, a file is an object containing certain information. To understand what data files, file structures and their interaction are, it is better to give an example from life, let's say, compare these concepts with an ordinary book.
Everyone knows that in almost any book you can find a cover, pages, table of contents, chapters and sections. For the simplest understanding, the cover- this is the entire file system in the aggregate, pages - folders (directories) in which individual files are stored, contents - the file manager, chapters and sections - files containing specific information.
As a rule (not always, true), the designation of an object called a file consists of two parts: a name and an extension. Actually, the name can be absolutely arbitrary and set in different languages. An extension is a special designation of three or more Latin characters that indicates a data type. Simply put, by extension, you can understand which program the file is associated with, whether it is a system one, etc.
Opening a file by default in any operating system is done by double-clicking the mouse. However, it is not a fact that everything can be opened in this way. The simplest example: executable files in Windows with the.exe extension can be launched this way, but the same dynamic libraries, denoted as.dll in the extension, although they contain executable codes, nevertheless, cannot be opened in this way. This is due only to the fact that their content is accessed through other software components, or the code is called by specialized components of the operating system itself. But this is the simplest example.
Files (objects) that do not correspond to either the operating system or any program will not be so easy to open. Roughly speaking, not a single “OS” will understand what kind of opening tool is needed.run. In the best case, you will be asked to choose the appropriate program yourself from the provided list of possible solutions.
Files and file structure: computer science at the dawn of computer technology
Now let's see what information technology was like when the first computers appeared. It is believed that the main system used at that time was DOS, which is primitive in modern times, in which specialized commands had to be entered to access functions.
With the advent of the unique brainchild of Norton Commander, such a need not only disappeared (some commands still needed to be registered), but rather decreased. It is this file manager, based on our example, that can be called a table of contents, since all data stored on a hard drive or external media was clearly structured.
Files and folders
As is already clear, there are several basic types of objects in any system. The file and file structure, except for the main element (file), are inseparable from the concept of a folder. Sometimes this term is referred to as a "directory" or "directory". In fact, this is a section in which individual components are stored.
In principle, not to mention book pages, the concept of a folder can be expressed most clearly if you look at some chest of drawers with many drawers in which something lies. This “something” is the files, and the boxes are the directories.
Simple search examplesfiles
Based on the above, we can conclude about a quick search for information. In any currently existing "OS" there are funds for this purpose. In the same file manager (for example, Windows Explorer), in a special field, it is enough to enter at least part of the file name, after which the system will display all objects containing the entered string.
However, for a more accurate search, sometimes you need to know exactly where the file you are looking for is located. Roughly speaking, it is necessary to select a specific box in the chest of drawers where the item we need is located. The search itself is performed using a standard tool in the file manager, but you can also use a combination like Ctrl + F, which brings up the search string.
What is a file system?
Files and file structures cannot be imagined without understanding the file system. Note that file structure and file system are not the same thing. The structure is the main kind of organizing files, if you like, organizing data, but the file system is the method that determines how the structure works. In other words, this is the principle of data processing in terms of their placement on a hard disk or any other storage medium.
Today there are quite a lot of file systems. For example, the most famous for Windows since the development of computer technology have become FAT systems with 8, 16, 32 and 64 bit architecture, NTFS and ReFS. The file system, file structure, ordering method are closely related. But now a fewwords about the systems themselves.
Leaving aside technical details, it should be noted that the main difference between them is only that FAT has a larger cluster size for storage and accelerated access to small files, while NTFS and ReFS are optimized for large data sets and quick access to them at the maximum speed of reading information from the hard disk.
File operations
Now let's look at the file structure of operating systems from the other side. Operations with files that are provided in any "OS", in general, do not differ much.
Among the main ones are creating a file, opening, viewing, editing, saving, renaming, copying, moving, deleting, etc. Such actions are standard for all existing systems. However, there are also some specific functions.
Data archiving
Among the specific functions, first of all, we can highlight the compression of files and folders, called archiving, as well as the reverse process - extracting data from the archive. At the time of the development of the DOS system, the creation of archive data types was mainly limited to using the ARJ standard.
But with the advent of ZIP-archiving technologies, such processes have received a new development. Subsequently, a universal RAR archiver was also created. These technologies are now available in any operating system, even without the need to install additional software. The file structure of OS operations with files in this perspective is treated as virtual compression. Essentially, compression technologiesthey simply instruct the system to determine not the desired size, but a smaller one. The information volume of a file or folder itself does not change during archiving.
Controlling the display of objects
The concepts of "file structure", "file structure", etc. should also be considered from the point of view of the possibility of seeing the objects themselves. It's no secret that almost all modern PC users have come across the term "hidden files and folders".
What is this? This only means that the system has a restriction on the display of some objects (for example, system files and folders, so that the user does not accidentally delete them). That is, in physical terms, they do not disappear from the hard drive, it's just that the file manager does not see them.
To display all hidden objects, in the same "Explorer" you should use the "View" menu, where a check mark is placed on the corresponding tab in the line for displaying all hidden folders and files. After enabling this view, objects will have translucent icons.
Finding hidden objects can also be difficult. If you enter a file name or its extension, even if you specify a specific location, when the display of such objects is disabled, there will be no result (the system does not see them, after all). In order to find them, you need to enter the % symbol at the beginning and at the end of the root folder name. For example, to search for the AppData directory, which is hidden and located in a particular user's local settings folder, use the search string%USERPROFILE%\AppData. Only in this case the file and the file structure as a whole will receive the key to the relationship.
Conclusion
That's briefly and all that concerns the understanding of the basic terms. In principle, it is not so difficult to understand what a file and file structure are, using elementary examples. Finally, if you like, you can define these terms as bricks and the wall from which it is built. A brick is a file, a wall is a file structure, where each brick occupies a strictly defined place assigned only to it.
Specifically, some technical aspects or classical definitions adopted in programming and computer technologies were not specifically considered, so that the reader could understand the material at an elementary level.
