Chap3 -How Software & Hardware Working Together

8/2/2019 Chap3 -How Software & Hardware Working Together

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Software and Hardware

working together

BIOS Startup Program checks hardwareto make sure it is ready to be used

User provides specific instructions tosoftware on what to do

Software interacts directly with the CPU,

which controls the various underlyingmechanisms that make the computerwork as intended


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System Resources Defined

A tool used for communication betweenhardware and software


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The Boot Process

Functions performed Startup BIOS tests essential hardware

components (power-on self test [POST])

Setup information is used to configure bothhardware and software

Hardware components are assigned systemresources they will later use for communication

OS is loaded, configured, and executed Hardware devices are matched up with BIOS and

device drivers that control them

Some applications software may be loaded and

executed


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The Boot Process, Step by Step

Step 1: Power-on self test (POST)

Step 2: The ROM BIOS startup

program searches for and loads an OS

Step 3: The OS configures the systemand completes it own loading

Step 4: The user executes applicationssoftware


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Step 1: POST

The ROM BIOS startup program surveyshardware resources and needs, and assigns

system resources to meet those needs Begins by reading configuration information

stored in DIP switches, jumpers, and theCMOS chip and comparing that information to

the hardware present


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Step 1: POST


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Step 2: BIOS Finds and Loads

the OS

Most often the OS is loaded from logical driveC on the hard drive (Figure 2-4)

Configuration information on the CMOS chiptells startup BIOS where to look for the OS(Figure 2-5)

BIOS turns to that device, reads thebeginning files of the OS, copies them intomemory, then turns control over to the OS


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the OS


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the OS


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Step 3: The OS Completes the

Boot Process

The OS checks some of the samethings that startup BIOS checked (e.g.,

available memory and whether memoryis reliable)

The OS loads software to control the

mouse, a CD-ROM, a scanner, andother peripheral devices (generally havedevice drivers)


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Step 3: The OS Completes the

Boot Process


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Step 4: User Executes

Applications Software

The OS finds the applications software (on asecondary storage device) copies software

into memory, and turns control over to it User commands the applications software,

which makes requests to the OS, which usesthe system resources, system BIOS, and

device drivers to interface with and controlthe hardware


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Completion of the Boot Process

Boot process is completed afterAUTOEXEC.BAT has finished

executing In Windows 3.x, it is common to include

in AUTOEXEC.BAT the followingcommand to execute Windows eachtime the computer is booted:

C:\WINDOWS\WIN


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How Software Manages

Hardware Resources

System resources IRQs

I/O addresses Memory addresses

DMA channels

System resources are dependent oncertain lines on a bus on the systemboard


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The 8-bit and 16-bit ISA Bus

8-bit ISA bus An older bus used on early PCs of 1980s

Had eight lines for data 16-bit

8 additional data lines

5 additional IRQ lines 4 more DMA channels

4 additional address lines


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8-bit ISA bus


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16-bit ISA bus


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Interrupt Request Number

(IRQ)

Hardware interrupt

An event caused by a hardware device

signaling the CPU that it requires service

Interrupt request number (IRQ)

A line on a bus that is assigned to a device

and is used to signal the CPU for servicing


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Interrupt Request Numbers


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Interrupt Request Numbers


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Interrupt Request Numbers and

I/O Addresses for Devices


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Protecting Data, Software, and

Hardware

Saving and restoring setup informationin CMOS

Keeping OS rescue disks

Backing up the hard drive

Documentation

Damage from electricity


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Saving and Restoring Setup

Information in CMOS

Two common utility software programsfor backing up setup information to a

disk to be used to recover lost setupinformation

Nuts & Bolts

Norton Utilities


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Saving Setup Information Using

Nuts & Bolts


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Nuts & Bolts


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Norton Utilities


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Norton Utilities


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Norton Utilities


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Keeping OS Rescue Disks

Allows you to boot a computer

Essential for every computer


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Backing Up Your Hard Drive

Backup

An extra copy of a file or files made to a

different location or storage media


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Documentation

Keep hardware and softwaredocumentation well labeled in a safe

place


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Damage from Electricity

Computers and data can be destroyed by twokinds of electricity Static electricity (ESD or electrostatic discharge)

Power spikes, including lightning

Practical protection against damage Never touch the inside of a computer when it is

turned on

Be grounded when computer is on

Use devices for protection against electricalsurges and lightning


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Chapter Summary

How individual computer componentswork together to perform tasks

Documents

Chap3 -How Software & Hardware Working Together