Systems Software / The Operating System CSC October 14, 2010

What is Software? Intangible A file Performs tasks / jobs A set of instruction Run/executed by the Central Processing Unit (CPU) Must be in the computer’s memory to run

Two Types of Software Systems Software Applications Software

What is Systems Software Controls the system – Hardware – Software – Input / Output (I/O) Middle man Comprised of – Operating system (OS) – Utility Programs

Platform Computer processor & operating system

Flavor Version of an operating system

Systems Software Programs Mainframe computers – Unix Desktop / Laptop computers – Windows – Mac OSX – Linux

Unix Bell AT&T labs Runs on large computers

Windows Microsoft Bill Gates Leading market share Windows 3.1 Windows 9 Windows 98 Windows ME Windows 2000 Windows NT Windows XP Windows Vista Windows 7

Mac OSX Apple Computers Steve Jobs Control hardware & software Based on Unix

Linux Linus Tovalds Open source Based on Unix Free Distros

Operating System Parts Kernel – Heart of the operating system – Must be in memory while the computer is running – All the important tasks the OS must do User Interface – How a human gives commands to the OS

Types of Operating Systems Classify by Users – Single User – Multiple User Classify by Task – Single Task – Multitasking Real-time Systems

Operating System Jobs Controls the hardware Controls all the other software programs

Managing the Processor Controls the timing of events the processor works on REQUEST Operating System

Managing Memory The operating system allocates space in RAM for instructions and data RAM Operating System

Managing Peripheral Devices Co-ordinates system hardware Device drivers – Small programs – How to communicate with a device Plug and Play – Device device drivers included with systems software – Makes devices immediately usable

Managing Storage Handles where files are placed on a storage device Retrieves files from storage device & puts them in memory Remembers file details File allocation table / File allocation system

Application Software Interface Requests made by application programs to the OS – Save a document – Print a document – Open a document – Send an – Play a song

User Interface Enables you to interact with the computer Types of interfaces: – Command-driven interface – Menu-driven interface – Graphical user interface

Utility Programs Additional small programs Maybe added on later Help with maintenance Make the computer easier to use – Task Scheduler – Defrag – Screen savers – Install/ uninstall wizard

The Boot Process Step 1: The basic input/output system (BIOS) is activated Step 2: A power-on self-test (POST) checks attached hardware Step 3: The operating system loads into RAM Step 4: Configuration and customization settings are checked