The date of birth of the DOS operating system can be considered 1980, when the first development, called QDOS, was created. The system was most widely used in 1987 and is still in use today.
DOS Operating System : General Description
The system (operating) of a computer is a program that loads when the personal computer is turned on. It 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 the bootloader and are constantly present there. The first file implements the high-level basic services of MSDOS, and the second complements the basic system for input output.
Processing of user-entered commands is performed using a command processor, which is implemented using the COMMAND.COM file located on the disk with the kernel. Some DOS commands, such as DIR, TYPE, and others, are executed by the shell itself. They are called internal teams. The remaining external commands are carried out using external files that are loaded into memory and are also controlled by COMMAND.COM. After the program ends, the processor deletes from the program memory and reports on the readiness for further user actions.
External commands that the DOS operating system executes are delivered as separate files with the system. They perform actions of various servicing nature (disk verification, formatting, etc.).
In addition to the MSDOS I / O system, there are device drivers that provide custom applications for existing devices or service new ones. These programs are loaded into the PC memory together with the system, and their names are written in a special configuration file CONFIG.SYS. This makes it easier to add new devices without using system MSDOS files.
DOS Operating System: Key Features
The main responsibility of the system is the maintenance (creation, storage, deletion) of files that are similar to any other and representing a data set of a specific memory location. During processing, files are downloaded to the computer’s RAM , and this happens under the control of the system (operating system).
Each file should have a name, which can be complex and simple. The complex name is represented by the name of the file and its extension. Unlike other higher-level systems (Windows), on MS-DOS a file name can have a maximum of eight characters. A file extension indicates its type or affiliation with a program, for example, a data file or text.
Of course, compared to Windows, MS DOS is a completely different interface. If in the first system all the necessary tools and all the information is graphically presented on a computer screen, then working in the DOS system is more complicated and requires special skill and knowledge of the teams.
As an interface, when working in DOS, a black screen appears with a command line only. And, for example, to download a program or game (supported by this system) you will need to enter several commands.
After the advent of the Norton Commander program, working in the MS-DOS system has become much easier. Also, the DOS operating system acts as a single-tasking system, and, unlike Windows, does not allow working with two or more programs at the same time. Nevertheless, this system is still used and allows solving various specific problems. From under DOS, a program is launched to restore information, to check memory and solve other "iron" problems.