computer system and it class 1

Computer System Software Hardware Computers Today

CSE 101: Introduction to Computer Science

Lesson 1: An Overview on Computer Systems

Muhammed Tawfiq Chowdhury Lecturer

Department of Computer Science and Engineering Northern University Bangladesh

[email protected]



Outline

1 The Parts of The Computer System Computer System The Parts of Computer System

2 Software Brings The Machine to Life

Software Operating System Operating System Services Application Software

3 Hardware

Looking Inside the Machine How Computer Process Data?

4 Computers Today

Classification of Computers


Outline




3 Hardware


4 Computers Today

Classification of Computers 4


Computer System

What is a computer?

A computer is an electronic device which -

◮ can respond to a specific set of instructions in a well-

defined manner.

◮ can execute a pre-recorded list of instructions (a program). CSE 101: Introduction to Computer Science


Computer System: Characteristics

◮ Quick data-input, information-retrieval, and store data.

◮ Accurate results computation.

◮ Quick processing of arithmetic and logic operations.

◮ Continuous and persistent work-ability.

◮ Prompt decision making.

◮ Communicability with other computers through networks.


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3 Hardware


4 Computers Today



The Parts of Computer System

A complete computer system include four distinct parts.

1 Software

2 Hardware

3 Data

4 User CSE 101: Introduction to Computer Science



Software

Software - also called programs - consists of organized sets of

instructions for controlling the computer.

◮ Some programs exist for the computer’s use, to help it manage

its own tasks and devices.

◮ Other programs exist for the user, and enable the computer to

perform tasks for you, such as creating documents.

Hardware

A computer's hardware consists of electronic devices; the

parts you can see and touch. The term “device" refers to any

piece of hardware used by the computer, such as a keyboard,

monitor, modem, processor, etc.



Data

Data consists of raw facts, which the computer can manipulate and process into information that is useful to people.

Users

People are the computer's operators, or users. The end-users use programs in managing daily works.


Outline




3 Hardware


4 Computers Today



Software

What is Software? An organized list of computer instructions that tells the computer how to perform a certain task is called a Software. A software is often also called a program.

Software is classified into two classes:

◮ System software

◮ Application software



Software

What is System Software? System Software refers to the operating system and all utility programs that manage computer resources at a low level, such as compilers, loaders, linkers, and debuggers.

What is Application Software? Software programs designed for end-users are called Application

Software. Commonly used application software programs are

word processors, database systems, and spreadsheet programs.


Outline




3 Hardware


4 Computers Today



Operating Systems (OS)

What is an Operating System? A large software program that make the computer-hardware functional is called Operating System. It provides the following things.

◮ It provides an interface between the user and the

computer hardware.

◮ It provides a way for applications software to communicate

with the hardware.

◮ It manages the system resources such as memory and also

allocate CPU time to the task being run.

◮ It manages system security


Facilities of Operating Systems

Operating system provides the following facilities for the users:

◮ Program creation: it provides editors, debuggers, other

software development tools.

◮ Program execution: it loads files, performs input/output

(IO) operations.

◮ Access to IO devices: performs read and writes.

◮ Controlled access to files: provides protection

mechanisms, abstraction of underlying device.

◮ System access: controls access to the system, detects

error and response.


Functions of Operating Systems

Operating Systems provide the following functionality.

◮ User Interface

◮ Resource Management

◮ Task Management

◮ File Management

◮ Security

◮ Utilities


Functions of Operating Systems: User Interface

User Interface: The User Interfaces allow users to interact with the computers. It consists of the cursors, prompts, icons, menus, etc. User Interfaces can be:

◮ Command Driven Interface

◮ Menu Driven Interface

◮ Graphical User Interface




Command Driven Interface

◮ With a command-driven interface, you type in an instruction

which is usually abbreviated, in order to get something done.

◮ Some older operating systems, such as DOS and UNIX, use

command-line interfaces.



Menu Driven Interface

◮This type of user interface produce a list of commands or options available within a program and the user can make a selection by using either a mouse or a keyboard.




Graphical User

◮ Most modern operating systems, like Windows and the

Macintosh OS, provide a graphical user interface (GUI). ◮ A GUI is based on the desktop metaphor. Graphical objects

appear on a background (the desktop), representing resources you can use.

CSE 101: Introduction to Computer Science Computer System Software Hardware Computers Today

Functions of Operating Systems: Resource Management

Resource Management

◮ Processors: Allocation of processes to processors.

◮ Memory: Allocation of main memory to processes.

◮ IO devices: Access I/O devices, such as keyboard and Mouse.

◮ Files: Space allocation to files and maintenance.



Functions of Operating Systems: Task Management

Task Management

◮ The OS uses interrupt requests (IRQs) to maintain

organized communication with the CPU and other

pieces of hardware.

◮ Each hardware device is controlled by a piece of software,

called a driver, which allows the OS to activate and use

the device.

◮ The operating system provides the software necessary to

link computers and form a network.



Functions of Operating Systems: File Management

File Management

◮ The operating system keeps track of all the files on each disk.

◮ Users can make file management easier by creating a

hierarchical file system that includes folders and sub-

folders arranged in a logical order.



Functions of Operating Systems: Security

Security

◮ Protection of the systems and user resources from

intentional as well as careless misuse.

◮ Security deals usually with threats from outside of the

system that affects the integrity and availability of the

system.

◮ Applying security mechanisms to protect systems and

data, such as asking log-in credentials to access system,

applying encryption to protect information, etc.


Functions of Operating Systems: Utilities

Utilities

◮ A utility is a program that performs a task that is not

typically handled by the operating system.

◮ Some utilities enhance the operating system’s functionality.

◮ Some of the major categories of utilities include: ◮ File defragmentation ◮ Data compression ◮ Backup ◮ Antivirus ◮ Screen savers


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3 Hardware


4 Computers Today


CSE 101: Introduction to Computer


Operating System Services

Basic Services

◮ The operating system manages all the other programs

that run on the PC.

◮ The operating system provides services to programs and

the user, including file management, memory

management, and printing.

◮ To provide services to programs, the OS makes system

calls requesting other hardware and software resources

to perform tasks.



Sharing Information

◮ Some operating systems, such as Windows, enable

programs to share information.

◮ You can create data in one program and use it again in

other programs without re-creating it. ◮ Windows provides the clipboard, a special area that stores

data cut or copied from one document, so it can be re-used elsewhere.




Multi-tasking

◮ Multitasking is the capability of running multiple processes

simultaneously.

◮ A multitasking OS enables running multiple programs at

the same time.

◮ There are two types of multitasking: cooperative and

preemptive.


Outline




3 Hardware


4 Computers Today

Classification of Computers 4 CSE 101: Introduction to Computer Science


Application Software

What is Application Software?

Application software is the programs that designed for end-users, such as word processors, database systems, and spreadsheet programs.

Application Software can be divided in two major classes.

◮ General Application Program

◮ Specific Application Program




General Application Program General purpose application program is a type of software that

can be used for a variety of tasks. For example, word

processors can be used for drafting anything; drafting an

assignment or drafting a book or drafting a business deal.

Some of the General Application Programs are,

◮ Software Suite - MS Office

◮ Web Browser - Chrome, Firefox

◮ Desktop Publishing - Pagemaker, Publisher ◮ Database Management System - Oracle, MS Access



Specific Application Program Purpose-built customized software programs are called Specific

Application Program. Some of the Specific Application Program are:

◮ Accounting Software of a bank

◮ Sales Management of a shop

◮ E-commerce of an online-shop

◮ Inventory Control for a warehouse

◮ Pay-roll System of a company

◮ Ticket Reservation of a transportation company



Outline




3 Hardware


4 Computers Today

Classification of Computers 4 CSE 101: Introduction to Computer Science


The Parts of Computer System: Hardware

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

◮ Internal Hardware

◮ External Hardware


The Parts of Computer System: Hardware

Internal Hardware: An Internal Hardware means hardware that surrounded by the computer's casing. External Hardware: By external hardware, we mean all the computer device that we can see from outside.



Looking inside the machine

A computer hardware devices are categorized as follows: ◮ CPU

◮ Processor ◮ Memory ◮ Storage Device

◮ (I/O) Device ◮ Input Device ◮ Output Device



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3 Hardware


4 Computers Today



How Computer Process Data?

How computers process data? Computer processes data in a coordinated manner with the

help of hardware and software. Data 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 all the computer's devices together, enabling them to communicate.


How Computer Process Data?

The two main parts of a CPU are the Control Unit and the Arithmetic Logic Unit (ALU)


How Computer Process Data? - The Control Unit

What is the Control Unit?

Control Unit coordinates all the jobs running in a computer.

Control Unit performs the following things.

◮ The Control Unit is a part of CPU which directs the flow

of data through the CPU, and to and from other devices.

◮ The Control Unit stores the CPU’s instructions for all the

tasks the CPU can perform.



How Computer Process Data? - The Arithmetic Logic Unit

What is Arithmetic Logic Unit? Arithmetic Logic Unit manipulates data based on the given operation instructions. ALU can perform the following things.

◮ The actual manipulation of data takes place in the ALU.

◮ The ALU can perform arithmetic and logic operations.

◮ The following operation ALU can perform

Arithmetic Operations Logical Operations

+ addition =; 6= equal to, not equal to

subtraction > greater than

multiplication greater than equal to

division < less than

^ raise by power less than equal to


How Computer Process Data? - Machine Cycle

Machine Cycle

◮ The CPU follows a set of steps, called a machine cycle, for

each instruction it carries out. ◮ The machine cycle includes two smaller cycles: ◮ Instruction Cycle: the CPU “fetches” a command or data

from memory and “decodes” it for the processing. ◮ Execution Cycle: the CPU carries out the instruction, and may store the instruction’s result in memory.

CSE 101: Introduction to Computer Science CSE 101: Introduction to Computer Science


Looking inside the machine: Memory

Memory

◮ The smallest usable unit of measure for memory is the byte.

◮ Computers work with larger chunks of data, measured in multiple bytes, as shown below: ◮ 1 byte = 8 bits ◮ 1 kilobyte (KB) = 210 bytes = 1, 024 bytes ◮ 1 megabyte (MB) = 220 bytes = 1, 048, 576 bytes ◮ 1 gigabyte (GB) = 230 bytes = 1, 073, 741, 824 bytes ◮ 1 terabyte (TB) = 240 bytes = 1, 099, 511, 627, 776 bytes ◮ 1 petabyte (PB) = 250 bytes = 1, 125, 899, 906, 842, 624 bytes ◮ 1 exabyte (EB) = 260 bytes = 1, 152, 921, 504, 606, 846, 976

bytes Muhammad


Outline




3 Hardware


4 Computers Today



Computers Today

Today’s computers can be classified as follows.

◮ Supercomputers

◮ Mainframe Computers

◮ Minicomputers

◮ Workstations

◮ Microcomputers, or Personal Computers

Computers Today

Computers Today - Supercomputer

Supercomputers are typically one-of-a-kind custom designed

computer having ultra super speed of data processing capability.

The term supercomputer itself is rather fluid, and today's

supercomputer tends to become tomorrow's normal computer


Computers Today - Supercomputer

Common Uses of Super Computer Researchers, scientists, major universities, military agencies are the main users of supercomputers. Supercomputers are used for:

◮ Highly complex calculation-Intensive tasks such as

problems involving quantum mechanical physics,

weather forecasting, climate research etc.

◮ Conducting complex simulations, such as detonation of

nuclear weapons, research into nuclear fusion, DNA

sequence matching, cryptanalysis etc.


Computers Today - Mainframe Computer

Mainframe computers are computers used primarily by large

organizations for critical applications, bulk data processing

such as census, industry and consumer statistics, enterprise

resource planning, and transaction processing.


Computers Today - Mainframe Computer

The characteristics of Mainframe computers are:

The characteristics of Mainframe computers are:

◮ 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 users need access to shared data and programs.

◮ Nearly all mainframes have the ability to run multiple operating

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

number of virtual machines.


Computers Today - Minicomputer

Minicomputers are smaller than mainframes but larger than microcomputers.

◮ Minicomputers usually have multiple terminals.

◮ Minicomputers may be used as Network servers and Internet servers.



Computers Today - Workstations

Workstations are powerful single-user computers.

◮ Workstations are used for tasks that require a great deal of number-crunching power, such as product design and computer animation.

◮ Workstations are also often used as network and web servers.


Computers Today - Microcomputers

Microcomputers are more commonly known as personal computers.

The term \PC" is applied to IBM-PCs or compatible computers. ◮ Full-size desktop computers are the most common type of PC.

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


Thank You!

computer system and it class 1

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