System concept and hardware

L.A 2COMPUTER SYSTEMS

TOPICS

1. System Concept

2. Hardware

3. Software

4. Installation

5. Current and Future Developments

Define Computer Systems

• A computer system is defined as combination of components designed to process data and store files.

Meaning of

Input Process Output Storage

Input is any data or instruction entered into the computer system for processing.

The processing unit controls all activities within the system.

Output is data that has been processed into a useful form, called information

Storage is a location which data, instruction and information are saved for future use

Information Processing Cycle

Process Process OutputOutputInputInput

StorageStorage

Block diagram of Information Processing Cycle

(CPU)

Input Input is any data or instruction that we enter into the

computer system for processing.

Common way : typing on keyboard and pointing a mouse

Examples of input devices : Mouse Keyboard Joystick scanner

Process The processing unit

control all activities within the system.

Control unit repeat a set of four basic operation call machine cycle : Fetch Decode Execute Store

FetchFetch

Decode Decode Store Store

Execute Execute

1

2

3

4

Process To control and

coordinates operations in a computer system.

To manage main memory Fetch a program

instruction or data item from memory

Decode the program instruction into signals that computer can execute

Execute the instruction Store the results of

instruction to the memory

FetchFetch

Decode Decode Store Store

Execute Execute

1

2

3

4

3

SYSTEM CONCEPT

1. Overview of Computer Systems

2. Data Representation

3. Introduction to Binary Coding

4. Data Measurement

5. Clock Speed Measurement

Data Representation

• Recognize only two discrete states: on or off

• Use a binary system to recognize two states

• Use Number system with two unique digits: 0 and 1, called bits (short for binary digits)

How do computers represent data?

Data Representation

• Bit the smallest unit of data.

represented by the numbers 1 and 0 (binary system).

They correspond to the states of on and off, true and false, or yes and no.

– All digital data use the binary system to process the information. This information include letters, digits or special character.

Bit, Byte and Character

L.O :State the relationship of data representation: bit, byte and character.

Data Representation

• Byte – Eight bits grouped together as a unit

8 bits = 1 byte– Provides enough different combinations of 0s

and 1s to represent 256 individual characters• Numbers• Uppercase

and lowercase letters

• Punctuation marks

• Other.



Data Representation

• Character – One byte represents one character such as A, 7,

9 and +.


Eight bits grouped together as a unit are called a byte. A byte represents a single character in the computer.

bit

byte

character


Introduction to Binary Coding

ASCII—American Standard Code for Information Interchange

EBCDIC—Extended Binary Coded Decimal Interchange Code

Unicode—coding scheme capable of representing allworld’s languages

What are three popular coding systems to represent data?

ASCII Symbol EBCDIC

00110000 0 11110000

00110001 1 11110001

00110010 2 11110010

00110011 3 11110011

L.O :Explain the function of ASCII code.

ASCII

WHAT IS ASCII?– ASCII pronounced as "ask-key" stands for

the American Standard Code for Information Interchange and was proposed by ASA (American Standard Association) in 963 and was finalised in 1968.ASCII is a standard of 7-bit code used to represent characters, which include letters, numbers and punctuation marks.


ASCIIFUNCTIONS OF ASCII

– ASCII was established to achieve compatibility between various types of data processing equipment making it possible for the components to communicate with each other successfully.

– ASCII enables manufacturers to produce components that are assured to operate correctly in a computer.

– ASCII makes it possible for humans to interact with a computer. It also enables users

to purchase components that are compatible with their computer configurations.


• HOW ASCII WORKS IN A COMPUTER SYSTEM?

Step 2.An electronic signal for the capital letter T is sent to the system unit.

Step 3.The signal for the capital letter T is converted to its ASCII binary code (01010100) and is stored in memory for processing.

Step 1.The user presses the capital letter T (shift+T key) on the keyboard.

Step 4.After processing, the binary code for the capital letter T is converted to an image, and displayed on the output device.

T


ASCII

• KILOBYTE (KB)• In mathematics, 1 KB = 1000 bytes.• In computer, 1 KB = 1024 bytes or can be said as:

• 1 KB = 210 bytes• This is how we get the calculation for 1024 bytes.

• MEGABYTE (MB)• 1 MB = 1 048 576 bytes or it can be said as:• 1 MB = 220 bytes

• GIGABYTE (GB)• 1 GB = 1 073 741 824 bytes or it can be said as: • 1 GB = 230 bytes

• TERABYTE (TB)• 1 TB = 1 099 511 627 776 bytes or it can be said as:• 1 TB = 240 bytes

L.O :State the units of data measurement

Why is 1024 bytes = 1KB?20 = 121 = 222 = 423 = 8

24 = 1625 = 3226 = 64

27 = 12828 = 25629 = 512

210 = 1024

Data Measurement

L.O :State the units of clock speed measurement

Every microprocessor contains a system clock. The system clock controls the speed of all the operations within a computer. The speed of the clock is measured by how many cycles per second the clock makes.

The clock speed unit is measured in hertz. A hertz is one cycle per second.

megahertz (MHz) equals to one million cycles of the system clock

Gigahertz (GHz) equals to one billion cycles of the system clock

Clock Speed Measurement

Which is faster ?

Pentium 4 running at 2.4 GHz is approximately one-third faster than a Pentium 4 running at 1.8 GHz.

One way of comparing the performance of personal computers is by comparing their microprocessor speeds. Microprocessor speeds are determined by their clock speed and are usually expressed in gigahertz (GHz), billion of machine cycles per second.

HARDWARE

1. Input Device

2. Output Device

3. Motherboard

4. Storage

Input DevicesL.O :Identify the input devices used for text, graphic, audio and video

• Input is any data or instruction that you enter into the memory of a computer.

• Four types of input:

Text graphic sound video


• Input devices are any electronic device connected to a computer and produces input signals.

• Examples :


• Input devices for text :

• Input devices for graphic :


• Input devices for audio :

• Input devices for video :


• Pointing devices :

mouse Pointing stick touchpad

joystick trackball

Output DevicesL.O :Identify the input devices used for text, graphic, audio and video

• output is the result of data processing activity when it is presented external to the system .

• Four types of output:

An output device is hardware that is capable of delivering or showing information to one or more users.

Output Devices

Monitor printer LCD DLP

Photo printer speaker headphone woofer

L.O :Identify the location of ports

A port is an interface on a computer to which you can connect a device such as printer, flash drive and mouse

• What is the motherboard? Main circuit

board in system unit

Contains adapter cards, processor chips, andmemory chips

Also called system board

Motherboard

L.O :Identify the Location of the CPU, expansion slots, expansion cards, RAM slots, ports and connectors on the motherboard

L.O : Explain types and function of Primary Storage

• Computer storage is the holding of data in an electromagnetic form for access by a computer processor

• Function – To help users to store program and data– keep current data while being processed by the processor until

the information is saved in a storage media – stores instructions from a computer program

• 2 types of storage – Primary storage (RAM, ROM)– Secondary storage (magnetic medium, optical medium, flash

medium)

Storage

Primary Storage

• Random access memory (RAM)?

The more RAM a The more RAM a computer has, the computer has, the faster it respondsfaster it responds

Also called Also called main memory main memory

or primary or primary storagestorage

Most RAM is Most RAM is volatile, it is lost volatile, it is lost when computer’s when computer’s

power is power is turned offturned off

Memory chips that can be Memory chips that can be read from and written read from and written

to by processorto by processor

Primary Storage

• Read only memory (ROM)?

Memory chips that store Memory chips that store permanent data permanent data and instructionsand instructions

Nonvolatile memoryNonvolatile memory, it is not , it is not lost when computer’s lost when computer’s

power is turned offpower is turned off

Three types:Three types:FirmwareFirmware——Manufactured with Manufactured with permanently written permanently written data, instructions, data, instructions, or informationor information

EEPROMEEPROM ((eelectrically lectrically

eerasable rasable pprogrammable rogrammable rread-ead-oonly nly mmemory)—emory)—

Type of PROM Type of PROM containing microcode containing microcode

programmer programmer can erasecan erase

PROMPROM ((pprogrammable rogrammable

rread-ead-oonly nly mmemory)—emory)—

Blank ROM Blank ROM chip onto which chip onto which a programmer a programmer

can write permanentlycan write permanently

• Secondary storage is another alternative storage to keep your work and documents

• It is non-volatile, which means that it does not need power to maintain the information stored in it.

• It will store the information until it is erased

Secondary Storage

Secondary Storage

• Type of secondary storage:

System concept and hardware

Technology

data representation

data representation

ascii functions of ascii

bytes data measurement

data item

digital data

ascii binary code

byte character