DOS operating system: description and features

The date of birth of the operating system DOS can be considered 1980, when the first development was created, which was called QDOS. The system was most widely used in 1987 and is still in use.

DOS Operating System : General

The system (operating) computer is a program that loads when the personal computer is turned on. She carries out a dialogue with a person, manages the PC and its resources, launches various programs for execution. Thanks to the operating system, the user and application programs can conveniently communicate with PC devices (interface).

The core of the MSDOS system is the MSDOS.SYS and I0.SYS files, which are loaded into memory using a bootloader and are constantly there. The first file implements high-level basic MSDOS services, and the second complements the basic system for inputting output.

The processing of user input commands is performed using a command processor, which is implemented by means of the COMMAND.COM file located on the disk along with the kernel. Some commands in DOS, such as DIR, TYPE and others, are executed by the command processor itself. They are called internal teams. The remaining external commands are executed using external files that are loaded into memory and managed also by COMMAND.SOM. After the program finishes its work, the processor deletes the program from memory and reports the readiness for further execution of the user's actions.

The external commands that the DOS operating system performs are delivered as separate files along with the system. They perform actions of various servicing nature (disk checking, formatting, etc.).

An add-on to the MSDOS I / O system is device drivers that provide non-standard use of existing devices or service new ones. These programs are loaded into the PC's memory along with the system, and their names are registered in a special configuration file CONFIG.SYS. This makes it easier to add new devices without using system MSDOS files.

DOS operating system: basic functions

The main duty of the system is to maintain (create, store, delete) files that are similar to any other and represent a set of data of a specific memory location. When processing, files are loaded into the computer's RAM , and this happens under the control of the system (operating room).

Each file must have a name that can be complex and simple. A complex name is represented by the name of the file and its extension. Unlike other higher-level systems (Windows), in MS-DOS, the file name can have no more than eight characters. The file extension indicates its type or membership in a program, for example, a data file or a text file.

Of course, in comparison with Windows MS DOS - it's a completely different interface. If in the first system all the necessary tools and all information are graphically represented on the computer screen, then the work in the DOS system is more complicated and requires special skills and knowledge of the commands.

As an interface, when working in the DOS system, a black screen appears with the command line alone. And, for example, to load a program or a game (supported by this system), you need to enter several commands.

After the appearance of Norton Commander, it became much easier to work in the MS-DOS system. Also, the DOS operating system is a one-task system, and it does not allow, unlike Windows, to work with two or more programs at the same time. Nevertheless, this system is still used and allows to solve various specific tasks. From under DOS, a program is launched to restore information, to test memory and solve other "iron" problems.