Operating systems

For each computer model, individual operating systems are developed. Moreover, for the same model, as a rule, there are several different operating systems with different purposes and different capabilities and properties. So, there are operating systems that can manage simultaneous execution of several programs - multi-program - or only one - single-program. There are operating systems that can serve only one - single-user - or simultaneously several people - multi-user OS. To support the work of local and global networks, network operating systems have been developed.

For each computer model, individual operating systems are developed

For IBM-compatible personal computers, operating systems have been developed: MS-DOS, Windows, Linux (a popular Unix version) and some others. One of the simplest operating systems for personal computers is the obsolete single-user and single-program MS-DOS. Its first version was developed back in 1981-1982. Operating systems of the Windows 9x family are multi-program, but single-user, and the Windows NT/2000/XP and Linux families are multiprogram, multi-user and network.

For each of the operating systems, a huge number of programs have been developed. These programs can only be run under the operating system for which they are designed. Therefore, along with the term "hardware platforms" discussed in the second chapter, the term "software platforms" is used, which refers to certain operating systems, as well as restrictions and requirements imposed on them by programs. In addition, about programs written to work with a particular operating system, they say that they "work in the environment." Recently, the term "Intel platform" came into use, which refers to a combination of a hardware platform based on the Intel processor and the software platform of the Windows operating system.

The main functions of operating systems: execution of program requests (input and output data, start and stop other programs, allocate and release additional memory, etc.); loading programs into RAM and executing them; standardized access to peripheral devices; memory management (distribution between processes, virtual memory organization); control access to data on non-volatile media; providing the user interface; saving system error information.

There are applications of computer technology for which operating systems are not needed. For example, embedded microcomputers contained in many household appliances, cars, simple cell phones, constantly execute only one program that starts up on power-up. Many simple game consoles - also representing specialized microcomputers - can do without an operating system, launching the program written on the inserted CD into the device when turned on.