Introduction to Operating System (OS)
An operating system (OS) is a crucial piece of software that manages the overall operation of a computer. It serves as an interface between hardware and application programs, enabling tasks such as disk formatting, file manipulation, memory allocation, I/O operations, and interrupt handling.
In a multiuser system, the OS allows users to share CPU time and system resources while facilitating inter-task communication, timers, clocks, and memory management. Essentially, an OS acts as a resource manager.
The operating system can be defined as a collection of system calls or functions that provide an interface between hardware and application programs. It manages computer hardware resources and hosts applications.
Common OS features include multitasking, synchronization, interrupt and event handling, input/output, inter-task communication, timers, clocks, and memory management.
The core of the OS is the Kernel, a small, highly optimized set of libraries. The Kernel is a program that forms the central core of an operating system, controlling everything in the system. It loads into memory during system startup and remains there throughout the session, providing essential services like memory management, process management, file management, and I/O management through system calls.
Popular Operating Systems include Windows, MacOS, MS-DOS, Linux, Unix, Xenix, and Android.
Real-Time Systems
Real-time systems are those where system correctness depends not only on output but also on the timing constraints of when results are produced. There are two types of real-time systems:
- Soft real-time systems, where system performance degrades but is not destroyed if timing deadlines are not met (e.g., air conditioner, TV remote), and
- Hard real-time systems, where failure to meet deadlines can lead to catastrophic consequences (e.g., air navigation system, nuclear power plant).
Typical Real-Time Applications
- Digital Control
- Command and Control
- Signal Processing
- Telecommunication Systems
- Defense
Examples of Real Time Applications
- In automobile engineering, the real time systems control the engine and brakes of the vehicle and regulate traffic lights for smooth travel.
- In air craft monitoring, the real time systems schedule and monitor the takeoff and landing of the planes, make it fly, maintain the flight path, and avoid accidents.
- The real time patient care system monitor and regulate the blood pressure and heart beats of the patient and also, they can entertain people with electronic games, TV and music.
- The real time systems are found in Air Traffic Control system also. The Air Traffic Control (ATC) system regulates the flow of flights to each destination airport. It does so by assigning to each aircraft an arrival time and enroute to the destination.
- The real time systems are important in industries also. For example, a system of robots perform assembly tasks and repairs in a factory or chemical industries where human beings cannot enter.
- An avionics system for a military aircraft, the real time systems perform the tracking and ballistic computations and coordinates the RADAR and weapon control systems.
- Digital filtering, video and voice compressing/decompression, and radar signal processing are the major applications of real time systems in signal processing.
- Another interesting application is the real-time database systems that refers to a diverse spectrum of information systems, ranging from stock price quotation systems, to track records databases, to real-time file systems.
- Real time systems are also found in Supervisory Control and Data Acquisition (SCADA). In SCADA systems the sensors are placed at different geographical points to collect the raw data and this data are processed and stored in a Real time data base.
- Robots used in nuclear power stations, to handle the radioactive material and other dangerous materials.
- Real time system applications are also found in office automation where LASER printers and FAX machines are used.
