System Software.

Operating systems.

​An OS is software that controls the hardware and interact with application software.


Page 138 Chapter 5

User-system interface

• It enables the user to make the software do meaningful tasks.

WIMP and post-WIMP

• Windows, icons, menu and pointing device.

  
  

• Touch screens.

Operating system tasks

Why do we need an OS?

A computer needs an operating system to coordinate and manage all the hardware, making it functional and efficient.

The OS manages memory, provides a user interface for human interaction, ensures security by handling permissions, and simplifies hardware management for software applications.

Memory management

• Memory optimisation

• Memory organisation

• Memory protection

​Three important aspects of memory management:

Memory Protection

• Memory protection ensures that programs cannot access memory being used by other programs.

Memory Optimization.

• Memory optimization manages how memory is allocated and deallocated when multiple applications run simultaneously.

• It tracks both allocated and free memory, ensuring efficient use.

• To maintain optimal performance, it may also swap data to and from the HDD or SSD.

Memory Organization

• Memory organization determines how much memory is assigned to an application and how it is efficiently divided.

• Also it makes use of Virtual memory (Memory reserve in the hard drive for when the RAM cannot store large documents).

Organization vs Optimization

• Memory Organization: This is about how memory is structured and divided up to handle tasks separately and safely. The goal is mainly to keep tasks organized and isolated from one another, which makes the system stable.

• Memory Optimization: This is about improving the performance of memory usage. The goal is to make the system run faster and use memory more efficiently, reducing waste and preventing the system from slowing down over time.

Security management

• Data recovery in cases of data loss.

• Prevention of intrusion (Antivirus)

• Privacy (Using a username and a password for login in the system)

​The OS also has a error detection system for when some process or component fails and it is able to offer error diagnostics.

Process management

• Multiple processes can run simultaneously and each process needs access to the resources provide by the computer system.

​Requires RAM and processing power

Resource management

• The Operating system provides resource management to achieved the best efficiency in computer system use.

• ​Schedule the process

• Resolve conflicts when 2 processes require the same resource.

Hardware management

Involves all input and output peripheral devices.

• Facilitates communication through device drivers between the hardware and the software.

• Ensures that the software use the hardware effectively to perform specific task.

• If a developer write a program does not need to know how the hardware works.

File management

Three main features of file management:

• Naming convention

• Directory structure

• Access control to the files

Software designed to perform specific task that help to maintain the correct functionality of the computer system.

​

This programs are executed by the user or by the Operating System when necessary.

Page 143

​Utility Software

This utility software primarily helps in two ways:

1. ​Creating the File System.

2. Managing memory allocation.
   

Utility software

A hard disk formatter can also detect and mark damaged sectors during a full format.

1. Identifying Bad Sectors.

2. Preventing Use of Damaged Sectors.

3. Managing Usable Space.
   

Hard disk formatter

Also known as antivirus software, it is a type of utility software designed to detect, prevent, and remove malicious software (malware), including viruses, worms, Trojans, ransomware, spyware, and other harmful programs that can damage or compromise your computer.

Virus checkers

Defragmentation software

Defragmentation

​Fragmentation

​File 2 deleted. And File 1 extended.

​File 3 extended.

Disk compression and file compression

​​The main purpose of compression software is to reduce file sizes for easier storage, sharing, and transfer.

​When needed, the software can then decompress the files to restore them to their original size and format.

Create copies of the files in case of data loss.

Key functions:

Back-up software

1. ​Full back-up

2. Incremental & Differential Backups

3. Scheduling Backups

4. Restoring Data

Program libraries

​​When developing software, programmers and developers use what others build before.

Library program.
Library routines.

Example: Nintendo switch.

Program libraries

State what is meant by a program library.


Pre-written code that can be imported and used by another program.

Program libraries

The subroutines are use to reduce time and effort needed.

Here and example of how the Source Code is compile and make use of the program libraries.

Program libraries

​​Dynamic Link Libraries Files (.dll files).

Collection of executable functions and procedures that can be dynamically loaded and accessed during runtime.