The primary functions of an operating system (OS) can be summarized into the following:

1. Process Management: The OS manages the creation, execution, and termination of processes (programs) running on the computer. It allocates system resources such as CPU time, memory, and I/O devices to each process.
2. Memory Management: The OS manages the computer’s memory, allocating it to running programs and ensuring that each program runs in its own memory space, preventing conflicts and crashes.
3. File System Management: The OS provides a file system, which allows programs to read and write files to storage devices such as hard drives, solid-state drives, and flash drives. It manages file creation, deletion, and modification, as well as access control and permissions.
4. Input/Output (I/O) Management: The OS manages input/output operations between devices such as keyboards, mice, printers, and monitors. It provides a standardized interface for programs to interact with these devices.
5. Security: The OS provides mechanisms for controlling access to computer resources, such as user authentication, access control, and encryption. It protects the system from unauthorized access, malware, and viruses.
6. Interrupt Handling: The OS handles interrupts generated by hardware devices, such as keyboard presses or disk completion, and schedules the corresponding interrupt service routines.
7. Resource Allocation: The OS manages the allocation and deallocation of system resources such as CPU time, memory, and I/O devices to running programs.
8. Job Scheduling: The OS schedules jobs (programs) for execution, prioritizing them based on factors such as priority, time of submission, and resource availability.
9. Error Handling: The OS provides error-handling mechanisms to detect and recover from system errors, such as program crashes or hardware failures.
10. User Interface: The OS provides a user interface, such as a command-line interface (CLI) or graphical user interface (GUI), that allows users to interact with the system and access its services.
11. Networking: The OS manages network connections, allowing programs to communicate with other devices on a network.
12. Device Management: The OS manages the installation, configuration, and operation of hardware devices, such as printers, scanners, and graphics cards.

These primary functions enable the operating system to manage the computer’s hardware and software resources, providing a platform for running applications and services.