In order to understand the principles by which computer systems function, it’s not enough just to interact with the “OS” on a visual level. For a full understanding of what is happening, you should clearly imagine what a file and file structure are. When considering this topic, it will be indicated why this is necessary.
The concept of 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 the program plan.
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, say, compare these concepts with a regular book.
Everyone knows that in almost any book you can find cover, pages, table of contents, chapters and sections. For the simplest understanding, a cover is an entire file system in a whole, pages are folders (directories) in which separate files are stored, a table of contents is a file manager, chapters and sections are files containing specific information.
As a rule (not always, true), the designation of an object called a file consists of two parts: name and extension. Actually, the name can be absolutely arbitrary and can be 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 mapped to, whether it is a system file, and so on.
Opening the default file in any operating system is a double click. However, it is not a fact that everything can be discovered in this way. The simplest example: executable files on Windows with the extension .exe can be launched in this way, but the same dynamic libraries in the extension designated as .dll, although they contain executable codes, nevertheless, do not open in this way. This is due only to the fact that their contents are 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 match either the operating system or any program will not be easy to open. Roughly speaking, not a single “OS” will understand which tool to open needs to be launched. In the best case, it will be offered to choose the appropriate program from the list of probable 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 was primitive today, in which specialized commands had to be entered to access functions.
With the advent of the unique offspring of Norton Commander, such a need not only disappeared (some teams still needed to be prescribed), but rather decreased. It is this file manager, based on our example, that can be called a table of contents, since all the data stored on the hard disk or external media was clearly structured.
Files and folders
As already clear, in any system there are several main types of objects. The file and file structure, in addition to the main element (file), are inseparable from the concept of a folder. Sometimes this term is referred to as a "directory" or "directory". In essence, this is the section where the 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 File Search Examples
Based on the foregoing, we can conclude about a quick search of information. In any existing "OSes" 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 is located. Roughly speaking, you need to select a specific box in the chest of drawers where the item we need is located. The search itself is performed using the standard tool in the file manager, but you can use a combination like Ctrl + F, which calls the search string.
What is a file system?
Files and file structures cannot be imagined without understanding the file system. Note that the file structure and file system are not the same thing. Structure is the main way of organizing files, if you want, of organizing data, but the file system is a method that determines the operation of the structure. In other words, this is the principle of data processing in terms of their placement on the hard drive or any other storage medium.
Today, file systems can be found quite a lot. For example, the most famous for Windows since the development of computer technology have become FAT systems with the architecture of 8, 16, 32 and 64 bits, NTFS and ReFS. The file system, file structure, and ordering method are closely related. But now a few words about the systems themselves.
Not to mention the technical details, it should be noted that the main difference between them is only that the FAT has a larger cluster size for storage and faster access to small files, while NTFS and ReFS are optimized for large data arrays and quick access to them on maximum speed of reading information from the hard drive.
File operations
Now let's look at the other side of what constitutes the file structure of operating systems. Operations with files that are provided for 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 some specific features.
Data archiving
Among the specific functions, first of all, one can distinguish 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 archival data types basically came down to using the ARJ standard.
But with the advent of ZIP archiving technologies, such processes have gained new development. Subsequently, the universal RAR archiver was created. These technologies are now presented in any "OS" even without the need to install additional software. The file structure of the OS file operations in this view is treated as virtual compression. In fact, compression technologies simply give the system an indication that it determines not the desired size, but a smaller one. The informational volume of a file or folder does not change during archiving.
Object display control
The concepts of “file structure”, “file structure”, etc. should also be considered in terms of the possibility of seeing the objects themselves. It's no secret that almost all users of modern PCs came up with the term “hidden files and folders”.
What it is? This only means that the system has a restriction on the display of certain 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, just the file manager does not see them.
To display all hidden objects, in the same "Explorer" you should use the "View" menu, where a checkmark is placed in the display line of all hidden folders and files on the corresponding tab. After enabling this kind of objects will have translucent icons.
Finding hidden objects can also be difficult. If you enter a file name or its extension, even with a specific location with the display off, such objects will not result (the system does not see them). 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 the local settings folder of a specific user, you should 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 everything regarding understanding the basic terms. In principle, to understand what a file and file structure are, using elementary examples is not so difficult. Finally, if you want, you can define these terms as the bricks and the wall from which it is composed. A brick is a file, a wall is a file structure, where each brick occupies a strictly defined place reserved only for it.
Some technical aspects or classical definitions adopted in programming and computer technologies were not specifically considered so that the material could be understood by the reader at an elementary level.