An operating system is the software that runs behind the scenes on computers, governing the hardware components like memory files, file systems, and input/output devices like keyboards, monitors printers, modems and keyboards. It also manages access to the central processing unit, or CPU.

Multitasking is a concept that allows multiple programs to run simultaneously on an OS. This is possible because the OS allocates system resources, such as CPU time and memory space for a program in execution. It monitors the program’s usage of these resources and ensures that the program does not interfere with other programs that are using these same resources.

Operating systems keep track of where files are located and their status on the computer’s disk. They create virtual directories and store metadata, including the date of creation or modification. An OS also makes it easy for applications to connect to the hardware of a computer via drivers. These drivers translate the proprietary language of the hardware into a standard that an operating system can understand.

When an application wishes to save a document, it connects to the kernel of the operating system. This is because the application cannot directly access the drive, and requires drivers to communicate with it. The operating system then creates and translates the file request into logical operation, and the hardware is then utilized according to the instructions.