Lecture 1


Lecture 1:

The Computer and Information Systems

Dr Yingchao ZHAO

After this lecture, you should be able to:

Describe the different components of an information system

Describe the different types of computers.

List out the different basic components in a computer.

Understand the basic types of memory .

We are surrounded by various kinds of computers nowadays

A computer is an electronic device , operating under the control of instructions stored in its own memory.

A computer can accept data, process the data according to specified rules, produce results, store results for future use, and communicate results with others.

The Information

Processing Cycle

Collects data



Produces information


Computers process data into information.


Raw, unprocessed facts, including text, numbers, images, audio, video, etc.


Data that have been collected and processed into a meaningful form helps decision making

An Information System has

five parts


People – End users

Procedures – The rules or guidelines people follow when using software, hardware, and data are procedures.

Typically, these procedures are documented in manuals written by computer specialists.

Software – A program consists of the step-by-step instructions that tell the computer how to do its work. Software is another name for a program.

The purpose of software is to convert data into information.

Hardware – The equipment that processes the data to create information is called hardware.

Data – The raw, unprocessed facts, including text, number, images, and sounds are called data.

Automatic Teller Machine (ATM)

Bar-code system for retailing

Pay-by-Phone system

Transportation system

 Any more …..

Personal computers

Mobile computers and mobile devices

Game consoles




Embedded computers

A personal computer can perform all of its input, processing, output, and storage activities by itself.

Two popular architectures

PC (Originated from IBM, usually uses Windows)

Apple (usually uses MacOS)

“Desktop Computers”

Full-scale computers

Notebook computer


Small enough to be held in hands

Handheld computer

Smart phone


Portable media player

Digital camera

A game console is a computing device designed for single-player or multi-player video games.

May be stationary or portable

A server controls access to the hardware, software and other resources on a network, to provide a centralized storage area for programs, data, and information.

A large, expensive, powerful computer that can handle hundreds or thousands of connected users simultaneously.

Fastest, most powerful, and most expensive computers. http://www.top500.org/system/177975

A special-purpose computer that functions as a component in a larger product.



• Mobile and digital telephones

• Digital televisions

• Cameras

• Video recorders

• DVD players and recorders

• Answering machines

Home Automation


• Thermostats

• Sprinkling systems

• Security monitoring systems

• Appliances

• Lights


• Antilock brakes

• Engine control modules

• Airbag controller

• Cruise control


Controllers and


• Remote monitoring systems

• Power monitors

• Machine controllers

• Medical devices

Computer Devices and Office


• Keyboards

• Printers

• Faxes

• Copiers

Physical components  hardware

Input Device

• Allows you to enter data and instructions into a computer

Output Device • Conveys information to one or more people

System Unit

• Contains the electronic components of the computer that are used to process data

Storage Device

• Holds data, instructions, and information for future use



• Enables a computer to send and receive data, instructions, and information to and from one or more computers or mobile devices

Input devices – allow you to enter data and instructions into a computer

Keyboard, Mouse, Trackball, Card-reader, Barcode reader, Scanner, RFID reader, etc.

Output devices – conveys information to one or more people

Monitor, speaker, printer, projector, etc.

The system unit is a case that contains electronic components of the computer used to process data.

Main components inside the system unit on a desk-top personal computer include:

Drive bay(s)

Power supply

Sound card

Video card




The motherboard is the main circuit board of the system unit, connecting all components.

A computer chip contains integrated circuits.

The processor, also called the CPU (Central Processing

Unit), interprets and carries out basic instructions that operate a computer.

Two main units inside a CPU,

Control Unit (CU)

Arithmetic and Logic Unit (ALU) by bfishadow

Have you heard about dual-core, quad-core, or multi-core CPUs?

The control unit (CU) is the component of the processor that directs and coordinates most of the operations in the computer.

The arithmetic and logic unit (ALU) performs arithmetic (e.g., +, -, *, /, etc.) and logical

(e.g., >, <, etc.) operations

The current trend of processor is to include more parallel processing units to execute more instructions at the same time.

Plan your use beforehand.


A port is the point at which a peripheral attaches to or communicates with a system unit.

Sometimes referred to as a jack.

A connector joins a cable to a port.

Cable from Wikipedia

A USB (Universal Serial Bus) port is one of the most commonly used port.

It can connect up to 127 different peripherals.

You can attach multiple peripherals using a single

USB port with a USB hub

Other popular ones include:

Firewire port eSATA port

Bluetooth port

IrDA port

SCSI port

Serial port

MIDI port

A Bluetooth adapter converts a USB port into a Bluetooth port.

A smart phone may communicate with a notebook computer using an IrDA port

Expansion slots connect to expansion buses.

Common types of expansion buses include:

PCI bus

PCI Express bus




USB and

FireWire bus

PC Card bus

The power supply converts the wall outlet

AC power into DC power.

Some external peripherals have an AC adapter, which is an external power supply.

Primary storage

Inside system unit

Very fast

Processors can directly access the data inside main memory (RAM).


All contents are gone when the system is turned off.

Memory consists of electronic components that store

 instructions waiting to be executed by the processor, data needed by those instructions, and results of processing of data

Memory usually also stores these things:

The operating system and other system software

Application programs

Data being processed and the resulting information

Two types of memory in system:

Volatile memory

Loses its contents when power is turned off

Example includes


Nonvolatile memory

Does not lose contents when power is removed

Examples include

ROM, flash memory, and CMOS

Three basic types of RAM chips exist:

Dynamic RAM


Static RAM




RAM chips usually reside on a memory module , and are inserted into memory slots on motherboard.

The amount of RAM required in a computer often depends on the types of software applications you plan to use.

Cache memory are small, expensive, fast memory modules.

Frequently accessed instructions & data are

“cached” (stored in cache) to improve computer performance.

Some cache resides inside the processor chip.

ROM (Read-Only Memory) refers to memory chips that store permanent data and instructions.

E.g., BIOS, firmware

A PROM (programmable ROM) chip is a blank

ROM chip that can be written once.

EEPROM (Electrically Erasable PROM) chip can be erased and re-programmed.

It is important for us to know how to use computers nowadays.

Various types of computers are introduced.

Personal computers, Mobile devices, Mainframes,

Supercomputers, Game consoles, etc.

Functional components in the system unit of a computer are described.



Motherboards RAM

Ports Buses Power supply