Learning Objectives

Operating systems classification

• Multiuser: when two or more users can work with programs and share peripheral devices (printer, scanner, fax)
• Multitasking: multiple applications operated at the same time
• Multiprocessing: more than one CPUs that can be shared
• Multithreading: smaller parts of a program are loaded when needed by OS
• Real-Time Operating System (RTOS): designed to allow computers to process and respond to the consistent input of information without delay

Basic Functions

• File and folder management
• An operating system creates a file structure on the computer hard drive where the data can be stored and retrieved
• Applications management
• Whenever a program is requested the operating system locates it and loads into the primary memory or RAM.
• Support for built-in utility programs
• The operating system comes with tools for maintenance and repairs. They identify the problem, they find lost files, repair the damaged ones and do backups for your data.
• Computer hardware control
• Operating systems facilitates the access of programs to the computer hardware through the BIOS and through device drivers.

Functions - continued

At the simplest level, an operating system does two things:

• It manages the hardware and software resources of the system. In a desktop computer, these resources include such things as the processor, memory, disk space, etc.
• The operating system plays the role of the good parent, making sure that each application gets the necessary resources while playing nicely with all the other applications

It provides a stable, consistent way for applications to deal with the hardware without having to know all the details of the hardware

Processor management

• One of the task under Application Management
• The heart of managing the processor comes down to two related issues:
• Ensuring that each process and application receives enough of the processor's time to function properly.
• Using as many processor cycles for real work as possible.
• Uses interrupts as an efficient way to communicate with its environments