Computer fundamentals

 Original chips were numbered 8086, 80286, 80386, 80486  You could buy chips from multiple vendors  Intel trademarked its chip as the Pentium  Pentium II, Pentium III, Pentium IV 

How a Computer Processes Data

Computer fundamentals

 Identify computer system components.

 Explain how the CPU works.

 Differentiate between RAM and ROM.

 Describe how data is represented.

 It needs some type of output device to give the result

of its processing to the user

 It needs some mechanism for storing data

Common System

Components

This figure shows

several devices that

are common

ponents of a

com-puter system.

System Motherboard

 Inside the case of a modern PC is the motherboard, which contains the electronic circuitry of the computer.

 Components found on the motherboard include

 The primary processing chip (CPU).

 The memory chips.

 Expansion slots for system interface cards.

 Ports for connecting external devices.

 BIOS chips that control system start-up.

 The circuitry that enables all of these components to

communicate.

power supply, and

some storage devices.

The Central Processing Unit

 The CPU is the brains of a computer system.

 The CPU is housed on a silicon chip that contains millions of switches and circuits.

 The CPU has two primary sections:

 Arithmetic/Logic Unit (ALU)

 This section performs arithmetic and logical operations.

 Control Unit

 This section is the boss of the CPU and coordinates all activity within the CPU It uses programming instructions to control what actions the CPU performs and when it performs them.

A CPU Chip

This figure shows a CPU chip for a

small computer The CPU determines

which of the millions of switches that

it contains should be turned on or off

by processing program statements

that tell it what to do.

Computer programs are written in

programming languages, and each

program statement causes one or more

actions to occur in the CPU

 Original chips were numbered

 8086, 80286, 80386, 80486

 You could buy chips from multiple vendors

 Intel trademarked its chip as the Pentium

 Pentium II, Pentium III, Pentium IV

 Clock speed (MHz or GHz) differentiates chips

 The central processing unit (cpu) or “brain”

of the PC

The Microprocessor

Types of Memory

 RAM – Random Access Memory

 This is short-term memory where data is processed while a program

is running.

 Data stored here can be accessed and modified as needed.

 This type of memory loses any data it holds if the computer is shut down.

 ROM – Read-Only Memory

 ROM is memory placed on the motherboard by the manufacturer and contains instructions that tell the computer how to start itself.

 This data cannot be accessed or modified by application programs.

 The contents of this memory are not lost when the computer is shut down.

surface (top & bottom)

 Storage = 1,024 bytes per

track-sector (top &

bottom) = 1K

 All data in one

cylinder can be read

without moving read/

write arm

The Instruction and

Execution Cycles

This figure illustrates

the basic cycle

The Machine Cycle

The instruction cycle

and one or more

exe-cution cycles create a

machine cycle, as

shown here Machine

cycles are measured in

microseconds, and the

faster your computer

can process machine

cycles, the faster it can

process data.

Computer System

Controllers

 A PC motherboard also contains several controllers.

 Controllers are devices that control the transfer of data between the computer and peripheral devices.

 Common peripheral devices include a mouse, a

monitor, a printer, a keyboard, and so on.

 Controllers are usually found on a single chip which can handle all usual devices.

Input Devices

 Larger monitors enable you to you run at higher resolutions; e.g., 19” to run 1024 x 768 comfortably

 A graphics card speeds processing

Lower Resolution (800 x 600)

Displays 20 rows and

8 columns

Higher Resolution (1024 x

768)

Displays 28 rows and

12 columns

The Digital Camera

 An image is stored on a photosensitive

computer chip, which converts the image to a series of pixels

Ports and Expansion Slots

 Serial and parallel ports are used to connect peripheral devices

to the computer circuitry.

 Serial devices (mice/monitors) transmit data one bit at a time.

 Parallel devices (printers) transmit data several bits at time.

 USB is a newer, high-speed method of connecting devices and

is beginning to replace serial and parallel ports.

 Expansion slots are electrical connections in the motherboard that can accept circuit cards to perform specific functions.

 These are commonly used to plug in sound cards, video cards, scanners, and other devices.

A Typical Expansion Card

It has electrical prongs along the bottom to plug into the expansion slot and make an electrical connection to the main board.

This port sticks out of the back of the PC case and is used to attach the device that this card controls.

Data Representation

of 1s and 0s.

ASCII) to determine what character or number is

represented by what series of binary digits.

byte.

its own unique combination of ones and zeros.

 Just about all computers perform the same

general options: input, processing, output, and

storage.

 Input, output, and processing devices grouped

together represent a computer system.

 The motherboard is the center of all processing.

basic controllers for the system.

Summary (continued)

 All calculations and comparisons take place in the ALU

 The control unit coordinates the CPU activities

 The motherboard contains different types of

memory

 Random access memory is volatile and is used to store instructions, data, and information

temporarily

 Peripheral devices are connected to the

computer through serial and parallel ports.

Summary (continued)

 The Universal Serial Bus is a new standard expected

to replace serial and parallel ports

 Expansion boards are used to connect specialized

peripheral devices or to add more memory to the

computer

 The ASCII code is a standard code used to represent the alphabet, numbers, symbols, and punctuation

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