1.2.1 Systems Software( a. Need, purpose, function of Operating Systems)

What is the operating system?

- System software that manages a computer's hardware and software resources

- acts as an intermediary between the user and the computer

- loaded when computer boots up

Computers cannot be used directly with raw hardware because hardware components are complex and work only with electrical signals. Why is OS needed?

- Acts as an interface between the user and hardware

- Manages hardware resources

- Enables multitasking

- Provides a stable and consistent environment

How does OS acts as an interface between the user and hardware?

Without an OS, users couldn't interact with the computer in a meaningful way. OS provides an interface, such as a graphical user interface (GUI,CLI), that simplifies tasks like opening files or running programs. It hides the complexity of the hardware

What hardware does OS manage?

-Memory (RAM)

-CPU (processor time)

-Storage devices

-Input/Output devices

How does OS enable multitasking?

-Allows multiple programs to run as if at the same time

-Prevents applications from interfering with each other

What is the purpose of the OS?

1. Resource Management

2. Abstraction

3. Convenience

How does the OS manage resources?

Ensures fair and efficient allocation of:

-CPU time

-Memory

-Secondary storage

-I/O devices

How does OS use abstraction?

Hides hardware complexity by providing:

-Files instead of disk sectors

-Windows instead of raw pixels

-Virtual memory instead of physical RAM only

What functions does OS provide?

- User interface

- Memory management

- Interrupt handling

- Processor scheduling

What is a user interface?

A system that allows a computer and a user to interact and perform useful functions. Hides complexity of the hardware

What is memory management?

process of controlling and coordinating a computer's memory

OS:

-Allocates RAM to programs

-Ensures programs do not access each other's memory

-Manages virtual memory (swap space/page file)

What is interrupt handling?

Will allow the O/S to pause a program running to allow a new instruction to be handled. example - whenever a new key is pressed or mouse moved

What is processor scheduling?

-Determines the order in which processes use the CPU

-Uses algorithms like round robin, FCFS, shortest job first

-Ensures fairness and efficiency