computer system and it class 1
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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
CSE 101: Introduction to Computer Science
Computer System Software Hardware Computers Today
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
Computer System Software Hardware Computers Today
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 4
Computer System Software Hardware Computers Today
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 Software Hardware Computers Today
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.
Computer System Software Hardware Computers Today
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 4
Computer System Software Hardware 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
Computer System Software Hardware Computers Today
The Parts of Computer System
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.
Computer System Software Hardware Computers Today
The Parts of Computer System
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.
Computer System Software Hardware Computers Today
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
Computer System Software Hardware 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
CSE 101: Introduction to Computer Science
Computer System Software Hardware Computers Today
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.
Computer System Software Hardware Computers Today
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
Computer System Software Hardware 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
Computer System Software Hardware Computers Today
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.
Computer System Software Hardware Computers Today
Functions of Operating Systems
Operating Systems provide the following functionality.
◮ User Interface
◮ Resource Management
◮ Task Management
◮ File Management
◮ Security
◮ Utilities
Computer System Software Hardware Computers Today
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
CSE 101: Introduction to Computer Science
Computer System Software Hardware Computers Today
Functions of Operating Systems: 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.
Computer System Software Hardware Computers Today
Functions of Operating Systems: User Interface
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.
CSE 101: Introduction to Computer Science
Computer System Software Hardware Computers Today
Functions of Operating Systems: User Interface
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.
CSE 101: Introduction to Computer Science
Computer System Software Hardware Computers Today
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.
CSE 101: Introduction to Computer Science
Computer System Software Hardware Computers Today
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.
CSE 101: Introduction to Computer Science
Computer System Software Hardware Computers Today
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.
Computer System Software Hardware Computers Today
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
Computer System Software Hardware Computers Today
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 4
CSE 101: Introduction to Computer
Computer System Software Hardware Computers Today
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.
Computer System Software Hardware Computers Today
Operating System Services
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.
CSE 101: Introduction to Computer Science
Computer System Software Hardware Computers Today
Operating System Services
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.
Computer System Software Hardware Computers Today
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 4 CSE 101: Introduction to Computer Science
Computer System Software Hardware Computers Today
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
CSE 101: Introduction to Computer Science
Computer System Software Hardware Computers Today
Application Software
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
Computer System Software Hardware Computers Today
Application Software
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
CSE 101: Introduction to Computer Science
Computer System Software Hardware Computers Today
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 4 CSE 101: Introduction to Computer Science
Computer System Software Hardware Computers Today
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
Computer System Software Hardware Computers Today
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.
CSE 101: Introduction to Computer Science
Computer System Software Hardware Computers Today
Looking inside the machine
A computer hardware devices are categorized as follows: ◮ CPU
◮ Processor ◮ Memory ◮ Storage Device
◮ (I/O) Device ◮ Input Device ◮ Output Device
CSE 101: Introduction to Computer Science
Computer System Software Hardware Computers Today
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 4
Computer System Software Hardware 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.
Computer System Software Hardware Computers Today
How Computer Process Data?
The two main parts of a CPU are the Control Unit and the Arithmetic Logic Unit (ALU)
Computer System Software Hardware Computers Today
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.
CSE 101: Introduction to Computer Science
Computer System Software Hardware Computers Today
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
Computer System Software Hardware Computers Today
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
Computer System Software Hardware Computers Today
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
Computer System Software Hardware Computers Today
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
Computer System Software Hardware 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
Computer System Software Hardware Computers Today
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.
Computer System Software Hardware Computers Today
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.
Computer System Software Hardware Computers Today
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.
Computer System Software Hardware Computers Today
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.
CSE 101: Introduction to Computer Science
Computer System Software Hardware Computers Today
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.
Computer System Software Hardware Computers Today
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.
Computer System Software Hardware Computers Today
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