Learning Objectives

Interrupts classification

• In general, there are hardware interrupts and software interrupts.
• A hardware interrupt occurs, for example, when an I/O operation is completed such as reading some data into the computer from a tape drive.
• A software interrupt occurs when an application program terminates or requests certain services from the operating system.

Interrupts - Summary

• Interrupts alter a program’s flow of control
• Interrupt causes transfer of control to an interrupt service routine (ISR)
• ISR is also called a handler
• When the ISR is completed, the original program resumes execution
• Hence, interrupts provide an efficient way to handle unanticipated events

Memory storage & management

When an operating system manages the computer's memory, there are two broad tasks to be accomplished:

• Each process must have enough memory in which to execute, and it can neither run into the memory space of another process nor be run into by another process.
• The different types of memory in the system must be used properly so that each process can run most effectively.

Device management

• The path between the operating system and virtually all hardware/device that are not on the computer's motherboard goes through a special program called a driver.
• Much of a driver's function is to be the translator between the electrical signals of the hardware subsystems and the high-level programming languages of the operating system and application programs.
• Drivers take data that the operating system has defined as a file and translate them into streams of bits placed in specific locations on storage devices, or a series of laser pulses in a printer.

Windows
Linux (UNIX)
Mac

MAC / Windows

• Single-user, multi-tasking
• Similar to Windows since it is the same type of OS
• However, when comparison is performed between them in terms of:
• Application
• Power
• Files and Folders
• GUI and etc
• Result: MAC obtains a slightly better score than Windows
• Comparison Website
• It is also possible to have BOTH operating systems on the same PC. However, it requires
• lots of free hard disk space
• emulation software that duplicates (provide an emulation of) the functions of one system with a different system
• a faster machine for faster installation time