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CMOS Configuration Chip

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Jumpers

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Software

The intelligence of the computer Computer programs, or instructions to

perform a specific task Determines what hardware is present Decides how hardware is configured

and utilized Uses hardware to perform tasks

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Three Types of Software and What They Do

Firmware (BIOS)• Controls computer’s input/output functions

Operating systems (OSs)• Provide instructions to hardware to perform

tasks Applications software

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Functions of BIOS and OS

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Firmware or BIOS

Provides basic instructions to hardware Often serves as the interface between

higher-level software and hardware

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Software Layers

A hierarchy determines how software interfaces so that high-level software can depend on low-level software to manage the hardware for it

Applications software depends on the OS to interface with hardware• Instructs hardware directly• Uses BIOS to provide the instructions• Uses device drivers

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Software Layers

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How Software Manages and Shares Information

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Operating Systems

Different operating systems are written to support different types of hardware systems and user needs

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Functions of Operating Systems

Manage BIOS Manage files on secondary storage devices Manage primary memory (RAM) Diagnose software and hardware problems Interface between hardware and software Perform housekeeping procedures requested

by user

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Starting Up the Operating System

OS programs must be copied from secondary storage into RAM (memory)

CPU then reads from one memory location in RAM to another to receive and follow instructions

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Starting Up the Operating System

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Interfacing with the Operating System

Command-driven interface Menu-driven interface Icon-driven interface (graphical user

interface or GUI)

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Command-driven Interface

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Menu-driven Interface

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Icon-driven Interface

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Survey of Operating Systems

Terms• Multitasking• Cooperative multitasking (task switching)• Preemptive multitasking• Environment• Windows 3.x operating environment

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Multitasking Environment

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Windows 3.x Operating Environment

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Comparison of Operating Systems

What kind of user interface is provided? Can the OS support multitasking? Can the OS easily manage large quantities of

primary memory (RAM) and secondary storage?

How many and what kinds of applications are written to work with the OS?

How powerful must the hardware be to make efficient use of the OS?

How does the OS perform in a network?

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Well-known Operating Systems

DOS (disk operating system) DOS with Windows 3.1 and 3.11 operating

environments Windows 95 and Windows 98 UNIX operating system Windows NT Windows 2000 OS/2 Macintosh operating system

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Disk Operating System (DOS)

First OS used by IBM microcomputers

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Disk Operating System (DOS)