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CSE 101

Lesson - 1

An Overview on

Computer System

Summer 2011



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This Lesson Includes Following section

The parts of the computer system

Looking Inside the machine

Software bring the machine to life

Computers Today



3

Page:3

A computer is a electronic device which-

can responds to a specific set ofinstructions in a well-defined manner.

can execute a prerecorded list of

instructions (a program).



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• User• Data

• Software• Hardware

What How

WhoWhich

A complete computer system includes four distinct parts Page:30



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A computer hardware consists of electronicdevice; the part we can see and touch.

The term "device" refers to any piece of hardware

used by the computer, keyboard, monitor, modem,mouse, etc.

A computer hardware consists of many differentpart. They are divided in two different groups.

Internal HardwareExternal Hardware

Page: 30 to 36 Lesson 1B



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Internal Hardware: An Internal Hardware means

hardware that surrounded by the computer's casing.

External Hardware: By external hardware we mean allthe computer device that we can see from outside.



Software

Page:39, 40 of book

What is Software?

Software is a set of electronic instructions that tells the

computer how to do certain tasks. A set of instructions is

often called a program.

The two most common types of programs are :

•System software• Application software.

What is System Software?

System Software refers to the operating system and all

utility programs that manage computer resources at a low

level. Systems software includes compilers, loaders,

linkers, and debuggers.

What is Application Software?

Applications software comprises programs designed for an

end user, such as word processors, database systems,and spreadsheet programs.



System Software – Operating System

Operating Systems: Page 209

An Operating system is a program that controls the hardware directly.

They provides an interface between the user and the computer

hardware.

They provide a way for applications software to communicate with the

hardware. The OS is a program that conducts the communication between

the various pieces of hardware like the video card, sound card, printer, the

motherboard and the applications.

They manage the system resourses such as memory and also allocate

CPU time to the task being run.

They manage system security.




Function of the Operating Systems: Page 209 to 220

UserInterface

ResourseManagement

TaskManagement

FileManagement

Secuity Utilities

User Interface

The User interface is what you see when you turn on the computer. It

Consists of the cursors, prompts, icons, menus, etc.



Operating System – User Interface

Type of User Interface: Page 212 to 216

User Interfaces can be:

1 • Command Driven

2 • Menu Driven

3 • Graphical (GUI – Graphical User Interface)



OS – User Interface – GUI

GUI Component : Page 212 to 214Main four components found in most graphical user interfaces.

Graphical User Interface

GUI ToolsApplication

and theInterface

MenusDialoge

Box



OS – User Interface – GUI

Designing a user interface: Page 210 to 214

To make an interface as user friendly as possible it is necessary

to take care when designing it and takes into account the

following:

User

Interface•Consistency

•Positioning of item on Screen

•Use of Color

•Use of sounds

•Availability of help




Operating system’s role in running software programs:

Page 212 to 220

1 •Basic Services

2 •Sharing Information

3

•Multi-Tasking



Software

Software

SystemSoftware

SystemManagement

Program

SystemSupportProgram

SystemDevelopment

Program

ApplicationSoftware

GenarelApplicationProgram

SpecificApplication

Progral

Page 39,40



The Part of Computer system - Data

Data consists of raw facts, which the computer canmanipulate and process into information that is useful topeople.

Computerized data is digital, meaning that it has beenreduced to digits, or numbers. The computer stores andreads all data as numbers.

Although computers use data in digital form, they convertdata into forms that people can understand, such as text,numerals, sounds, and images.

Page 31



The Part of Computer system - USERS

People are the computer's operators, orusers.

Some types of computers can operatewithout much intervention from people,

but personal computers are designedspecifically for use by people.

Page 30



Looking inside the machine

A computer hardware devices are categorizedas follows:

CPU

•Processor•Memory / Storage Device

•Control Unit

(I/O) Device

•

Input Device•Output Device



How Computer Process Data

Where Processing Occurs:

•The Control Unit•The Arithmetic Logic Unit

•Machine Cycles

•Processing takes place in the PC's central processing unit (CPU).

•The system's memory also plays a crucial role in processing data.

•Both the CPU and memory are

attached to the system's

motherboard, which connects allthe computer's devices together,

enabling them to communicate.

Page: 142




How Computer Process Data –

The Control Unit

The two main parts of a CPU are the control unit and the arithmetic logicunit (ALU)

• The control unit directs the flow of data through the CPU, and to

and from other devices.

• The control unitstores the CPU's

microcode, which

contains the

instructions for

all the tasks the

CPU canperform.

Page: 142





The Arithmatic Logic Unit

•The actual manipulation of data takes place in the ALU. Page 142

•The ALU can perform arithmetic and logic operations.

•The ALU is connected to a set of registers—small memory areas in the CPU, which hold

data and program instructions while they are being processed

Arithmetic

Operations

Logical

Operations

+ Add , equal to, not equal to

Subtract >, > greater than, not greater than

x Multiply <, < less than, not less than

Divide , greater than or equal to,

not greater than or equal to

^ Raise by a power , less than or equal to,

not less than or equal to

ALU Operations List





Machine Cycle

•The CPU follows a set of steps-called a machine cycle-for each instruction it

carries out.

•By using a technique called pipelining, many CPUs can process more than one

instruction at a time.

•The machine cycle includes two smaller cycles:

During the instruction cycle, the

CPU "fetches" a command or data

from memory and "decodes" it for the

CPU.

During the execution cycle, theCPU carries out the instruction, and

may store the instruction's result in

memory.

Page 142, 143

L ki i id th hi M



Looking inside the machine – Memory(Count.) The smallest usable unit of measure for memory is the byte

The amount of memory required to hold one character, like theletter A or the numeral 2. Computers work with larger chunks of data, measured in multiplebytes, as shown below:

1 •byte = 8 bits

1 •kilobyte (K / Kb) = 2^10 bytes = 1,024 bytes

1 •megabyte (M / MB) = 2^20 bytes = 1,048,576 bytes

1 •gigabyte (G / GB) = 2^30 bytes = 1,073,741,824 bytes

1 •terabyte (T / TB) = 2^40 bytes = 1,099,511,627,776 bytes

1 •petabyte (P / PB) = 2^50 bytes = 1,125,899,906,842,624 bytes

1 •1 exabyte (E / EB) = 2^60 bytes = 1,152,921,504,606,846,976 bytes

C t T d



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Computers Today

Supercomputers

Mainframe Computers

Minicomputers

Workstations

Microcomputers, orPersonal Computers

Page 9 to 15

S t



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Supercomputer

A supercomputer is a computer that is considered, or was considered atthe time of its introduction, to be at the frontline in terms of processingcapacity, particularly speed of calculation.

Supercomputers introduced in the 1960s were designed primarily bySeymour Cray at Control Data Corporation (CDC), and led the marketinto the 1970s until Cray left to form his own company, Cray Research.

Today, supercomputers are typically one-of-a-kind custom designs produced by "traditional" companies such as IBM and HP, who had

purchased many of the 1980s companies to gain their experience,although still specializes in building supercomputer

The term supercomputer itself is rather fluid, and today's supercomputertends to become tomorrow's normal computer.

S percomp ter



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Supercomputer –

Common Uses

Supercomputers are used for

Highly calculation- Intensive tasks such as problems involving quantum mechanical

physics,

Weather forecasting, climate research (including research into globalwarming),

Molecular modeling (computing the structures and properties ofchemical compounds, biological macromolecules, polymers, andcrystals),

Physical simulations (such as simulation of airplanes in wind tunnels,

Simulation of the detonation of nuclear weapons, and research intonuclear fusion),

Cryptanalysis, and the like. Major universities, military agencies. Scientific research laboratories are heavy users.

Page 15

S t T d



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Supercomputer – Today

Roadrunner is a supercomputer built by IBMat the Los Alamos National Laboratory inNew Mexico, USA. Currently the world'sfastest computer,

Price - US$133-million = TK 919,99,99,977.00

M i f C t



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Mainframe Computer

• Mainframes are computers used mainly by large organizations for critical

applications, typically bulk data processing such as census, industry andconsumer statistics, ERP, and financial transaction processing.

• Mainframe computers can support hundreds or thousands of users,

handling massive amounts of input, output, and storage.

• Mainframe computers are used in large organizations where many usersneed access to shared data and programs. Mainframes are also used as e-

commerce servers, handling transactions over the Internet.

• Nearly all mainframes have the ability to run (or host) multiple operating

systems and thereby operate not as a single computer but as a number of

virtual machines. In this role, a single mainframe can replace dozens or

even hundreds of smaller servers, reducing management and

administrative costs while providing greatly improved scalability and

reliability.



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Mini Computer

• Minicomputers are smaller than mainframes but

larger than microcomputers.• Minicomputers usually have multiple terminals.

• Minicomputers may be used as network serversand Internet servers.



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Workstations

• Workstations are powerful single-user

computers.• Workstations are used for tasks that require a

great deal of number-crunching power, such asproduct design and computer animation.

• Workstations are often used as network andInternet servers.



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Microcomputers

• Microcomputers are more commonly known as personalcomputers. The term "PC" is applied to IBM-PCs orcompatible computers.

• Full-size desktop computers are the most common type of

PC.

• Notebook (laptop) computers are used by people whoneed the power of a desktop system, but also portability.

•

Handheld PCs (such as PDAs) lack the power of adesktop or notebook PC, but offer features for users whoneed limited functions and small size.



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Microcomputers Today



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Any Question



Thank You

“Its not the end, its not even the beginning of the end.

Its only the end of beginning.”

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