Change startup option(System configuration utility)

Do have a problem with excess loading when computer startup due to some programs ???

Then you just want to change settings in "System Configuration Utility"

Follow the given step in order to remove staring of programs when computer logins :

=> Click 'Start'
=> Select 'Run'
=> Type 'msconfig'
=> Then a pop-up window appears namely 'System Configuration Utility'-> Select 'Startup' tab.
=> clear the ticks of which you don't want to start when your computer starts.

start > Run > type "msconfig" > OK > System Configuration Utility > Startup Tab > Clear ticks.

Secondary Memory

Secondary Memory

    The computer system deals with a large amount of data and softwares, to handle various needs.The primary memory has a limited storage capacity and is not permanent.An alternate to this problem is the secondary memory or secondary storage devices.

          Secondary memory is of permanent nature.Data in secondary memory remains there until it is overwritten with new data removed intentionally.They can also be retrieved at any time.Secondary storage devices are of many types and they vary in the capacity and media of storage.They are considered as an auxiliary component and can be attached to the CPU based on the application of the user.

         Earlier secondary memory existed in the form of punched cards, paper tapes, magnetic drums and magnetic tapes.Now the most commonly used secondary devices are magnetic disks and optical disks  

Some Secondary Storage devices :

♠ Magnetic Disks

♠ Floppy Disks

♠ Hard Disk

♠Optical Disk

♠ Compact Disk Read Only Memory (CDROM)

♠ WORM (Write Once, Read Many)

♠ Erasable Optical Disks

♠ Digital Video Disk (DVD)

♠ Magneto Optical Disk

Primary Memory

Primary Memory

        The primary memory of the computer is used to hold two distinct types of information, the data which is to be processed by the CPU and the set of of instruction to be executed next.The primary memory is capable of sending and receiving data at very high speed.The primary memory is classified into two

=>Random Access Memory (RAM)

=>Read Only Memory (ROM)

RAM : 

   

   RAM is used to to store data and instruction needed by the CPU for processing.Data can be stored and retrieved at random from anywhere with the same amount of time, no matter where the data is.Hence the name random access memory .RAM can be used for both reading(retrieving) and writing(storage) of data.So it is also called Read/Write memory.

   Data can be stored in RAM only temporarily because memory is electronic device and hence is of volatile nature.When electronic power is turned off all the contents of the RAM will be lost.CPU requires all the data and instruction under processing to be in the main memory (RAM).So data and instruction should be reloaded  to the main memory every time when the computer is turned on.

   RAM was one of the most expensive computer component to manufacture for many years.Vacuum tubes, transistors and magnetic cores were used in earlier times as memory.However with the invention of semiconductor technology the cost of manufacture and size of memory has drastically reduced.Today the usage of silicon chips has greatly increased the memory capacity of computers.Based on the characteristics of the electronic circuits, RAM exist in various forms like Static RAM, Dynamic RAM (DRAM), Synchronous Dynamic RAM (SDRAM).

ROM :

   Read only memory is a memory unit that can perform only read operations. it does not support storage or write operations.Binary informations stored in ROM are permanent nature and they are stored in the ROM chip at the time of manufacture itself.Hence ROM is of non volatile nature i.e., contents are not lost even if power is turned off.However components connected to the systems perform some basic input/output operations, initiates loading of software that are essential for the working of the computer system.ROM chip is also called Firmware because these instruction are permanently stored in it at the time of manufacturing.

     

     There are exists another three categories of ROM used in some computer system namely

=> PROM (Programmable ROM)

=> EPROM (Erasable Programmable ROM)

=> EEPROM (Electrically Erasable Programmable ROM)

Functional Units of a Computer

 Functional Units of a Computer

          The hardware of the computer system is a collection of electronic circuits and other devices.There are certain basic components or building blocks that exist in all computer system.These components are the Central Processing Unit (CPU), Memory, Input devices and the Output devices.A systematic interaction between these components is essential for the functioning of the computer.

Central Processing Unit (CPU)

    The CPU is referred to as the brain of the computer.The CPU controls the overall functioning of a system.It is the part of the computer where the actual processing of the data by taking input device , storing data in the memory and retrieving them when needed and directing the processed data  to the output device.The CPU comprises of  three parts

     => Arithmetic Logic Unit (ALU)

     => Memory 

     => Control Unit

(Click on topics for more info)

The other Functional units of computer are :

 ◘  Input Unit

 ◘  Output Unit

Computer Memory

                   Just like humans, computers rely a lot on memory.They need to process and store data, just like we do.However computers store data in digital format, which means the information can always be called up exactly the way it was stored.Also, unlike our memory computers memory didn't get worse overtime.While memory can refer to any medium of  data storage, it usually refers to RAM or Random access memory.While your computer boots up it loads the OS into its memory, or RAM.This allow your computer to access system function such as handling mouse and keystroke, since the event handlers are all loaded into RAM

                  RAM is a very high-speed type of memory, which make it deal for storing active programs and system process.It is different than Hard disc space  in that RAM is made up of physical memory chips, while hard disc are magnetic discs that spins inside a Hard drive.Accessing RAM is much faster than accessing the hard disc because RAM access is based electric charges, while hard drive need to seek to the correct part of the disc before accessing the data.However all the information stored in RAM is erased when computers's power is turned off..The hard disc on the other hand, store data magnetically without requiring electrical power.Another common type of memory is Flash memory, which is typically used for small devices such as Digital cameras, USB key-chain drives and portable music player like the iPod nano.This kind of memory, known as ' EEPROM ' or electrically erasable programmable read-only memory is convenient for portable devices.Since it stores information even its power source is turned off, but is smaller and more resilient than a Hard drive.To summaries, memory is the vital part of computers and other electronic devices to function.

The computer memory is mainly classified into two :

♣ Primary Memory

♣ Secondary Memory


(click on topics for more info)

Output Unit

Output Unit

           Output devices are used to communicate the processed information to the user.The results of the processing operation in machine readable form must be made available in a human readable form.The output devices translate processed data in machine readable form to s form that can be interpreted by humans.The most common types of output devices are Monitors, which resembles the television screen and printer, which copy from the computer onto paper.Outputs can be obtained in the form of drawings and voices.

Output Devices :

           To be effective, information must be produced in an usable form.An output device is any machine capable of representing information from a computer.Output devices can be divided into 2 : (i) Hard copy devices : Output is in direct usable form.They produce a permanent record on paper. (ii) Soft copy devices : Produce output that cannot be used directly.They do not produce a permanent record.Hard copy devices are slow compare to soft copy devices.Some hard copy devices are printers, plotters, etc.Examples of soft copy  devices are Visual Display unit (VDU),Liquid Crystal Displays(LCD), etc.

          Output devices are also classified as commonly used(VDU, Printers) and special purpose devices(Plotters, LCD, etc).

Input Unit

Input Unit

           The input devices are used to enter data to the computer system.There are many types of input devices depending on the nature of data to be entered.Key board is one of the most commonly used input device.It is used for alphanumeric data entry.Mouse is another common input device used to locate screen positions.There are also unusual input device that respond to voices and touch.The input device is also responsible for translation of data to a form that the computer system can understand

Input Devices :

         An input devices is any machine that is used to feed into the computer.Some of them are general purpose, that is they are used by all computers where as some others are special purpose which are used to input data in a specific way.Key board and Mouse can be considered as general purpose and special purpose input devices are optical mark readers, optical character readers, optical character readers and track ball.

Computer as a System

  Computer can be considered as a device made up of a combination of electronic and electromechanical components.As any other devices computer by itself has no intelligence.A computer comes to life only when it is connected to some other components .The computer along with these components make it a system - Computer System.

 The computer system is a combination of basically five elements.

♣ Hardware

♣ Software

♣ Users/People

♣ Procedures

♣ Data/Information

Hardware
   The physical equipments and components which one can see, touch and feel(tangible components) in a computer system are called hardware.

Software
  The instructions that tell the hardware how to perform a task is called software.The hardware does not know what to do without these instruction.

Users
   Users or people are considered as the most important of the computer system.They operate the hardware, create, the instructions to perform a particular task i.e., software, responds to present and coordinate the data     and information flow.

Procedures
   Procedures are the steps to be followed while a particular task is being performed using the computer system.These procedures may be documented or guided by the software that perform the task.

Data/Information
   The prime objective of a computer system is data processing.Data are raw, unevaluated facts and figures, concepts or instruction.This raw material is processed into useful information.Information is the product of data processing.

Connectivity
   A computer system as such can be set up to communicate with another computer system.The media used to connect the two systems like phone lines, artificial satellites, microwave stations are also considered as an element of the computer system.

Types Of Network

Types Of Network

    The development of network due to recent advances in communication technology makes it possible to transmit data in a large distances.Networks are classified into Local Area Network (LAN), Wide Area Network (WAN) and Metropolitan Area Network (MAN).

  Local Area Network

       Network used to interconnect computers in a single room, rooms, within a building or buildings of one area are normally called Local Area Network or LAN.Each node in a LAN has its own CPU which executes programs, but it also able to access data and devices any where on the LAN.This means that many users can share expensive devices such as laser printers and data.Users of LAN can communicate with each other by sending e-mail or engaging in chat session.

 Wide Area Network

      A WAN is a computer network that spans a relatively large geographical area.Typically a WAN consist of 2 or more LAN's connected together.Computers connected to a WAN use telephone lines or leased lines or satellite to connect together.The biggest WAN in existence is Internet.

 Metropolitan Area Network

      Another type  of network is Metropolitan Area Network.A MAN is a network spread over a city.for example s cable TV network that spread over a city, Connection of computers of branches of an organisation which spread over a city.

Computer Language

Computer Language 

    Computer Languages are means of giving instruction to the computer .They are classified into two types :

    ♦ High Level Language (HLL)

    ♦ Low Level Language (LLL)

High Level Languages (HLL)

   

        Instructions and expressions written in English like languages is known as High Level Languages.High Level Languages are designed to make programming very easy.That is all the instructions in HLL can be easily understood by any Human being.Some of the HLL are , COBOL, PASCAL, BASIC, FORTRAN, C++.

Low Level Languages (LLL) 

       Low Level Languages are classified into 2 types (1) Assembly Language (2) Machine Language.Machine Language is the Binary language (0's and 1's) which is the only language understood by the computer.In assembly language programs are developed using codes.Machine Language is very easy complex and it takes time to write.So  programs were developed using coding which can be remembered easily.For adding two numbers it uses  ADD.In this language we can use numeric codes for writing programs.

The languages written in Assembly languages and HLL are translated using Language processors.

Application Softwares

Application Softwares

          Programs which are developed in order to serve a particular application are known as application softwares.for example Microsoft Office, Tally etc.

          Application Softwares can further be subdivided into three categories.  

         ☻ Packages

         ☻ Utilities

         ☻ Customized Softwares

(A) Packages :

       System softwares manage the computer hardwares in order to make a platform for the application programs to run.It is application softwares that make the computer useful for people.Application programs can be written to do every task.In this category general purpose application softwares are known as Packages.The following are the different category of packages ;

     i) Word Processors

    ii) Spread Sheets

   iii) Presentation & Graphics

   iv) Database Packages 

    v) DTP Packages

(B) Utilities :

      Utilities are those programs which are designed to assist computer for its smooth functioning.Some of the utilities are backup utility, Disc defragmentation, Scanning of viruses etc.

Utility Programs :

    

     i) Text editor 

     ii) Backup Utility

    iii) Compression Utility

    iv) Disc Defragmentation 

     v) Virus Scanner

(C) Customized Software :

       Customized Software means programs which are developed for meeting user requirement to serve a particular application.These type of softwares is called Tailor made software.For instance a hospital wants to customize its information system and gets a software according to its needs.This software cannot be copied into another hospital as it may not fit the requirements of the that particular hospital.

  

Language Processors

Language Processors

      Language Processors is a classification of System softwares.Usually programmers prefer to write programs in one of the High Level Languages (HLL) because of its simplicity.But computer understands only machine languages (Binary Language).So it is quite necessary to process programs written in HLL and translate it to language which understood by the computer.The system programs which perform this job are language processors .The different language processors are given below :

1) Assembler 

          This language processor converts programs written in assembly language into machine language

2) Interpreter 

          This language processor converts a HLL program into machine language by converting and executing it line by line.If there is any error in one line, it reports and execution of the program is terminated(stopped) at the sane time.We can resume the execution of the program only after rectification of the errors.For errors, debugging interpreters is very much useful. 

3) Compiler 

          A program called compiler translate program written in HLL into machine language.They also provide a list of source program statements and error message along with the line number.If there are no syntax errors in the program, computers generate objects files.Translating using compiler is called compilation.If no errors it automatically run the program it self.

Operating system softwares

Operating system softwares

             Operating system softwares is the most  fundamental system software.It is one of the System software.The Operating system of a computer is a set of programs that works as an interface between the user and the hardware devices.OS usually supplied by the computer manufactures control the overall operations of a computer.Operating system perform a variety of tasks.It manages resource of the computer.They also retrieve data from secondary storage, schedule the jobs for the processor to perform.In addition, they coordinate input and output operations.The OS not only makes the system convenient to use but also use hardware in an efficient manner.egs:-

♥ Windows 98

♥ Windows 2000

♥ Windows XP

♥ Windows 7

♥ GNU/Linux

System Softwares

System Softwares

      

      System softwares is a set of programs which are written to manage its resources and control its operations.

     System softwares are further classified into two :

1)  Operating System softwares

2)  Language Processors 

(Click on the topics for more info )

Network Switch

Switch

    

      A Switch is a device that directs incoming data from any of the input channels to the specific output channels that will take to its intended destination.This reduces collision rate.Although a hub or a switch can be used to connect computers on a network, a switch is faster but more expensive than a hub.

Network Hub

Hub

  A hub is a device that is a distribution point to other devices on the network.A hub takes data that comes from one channel and sends it out to all other channel on the hub.

When a hub receives data from a PC on the network it transmits the data to all other PC's on the network.If two or more PC's on the network try to send data at the same time a collision is said to occur.When that happens all the PC's the perform certain functions to resolve the conflict.This slows the data transmission through the Hub.  

Protocols

Protocols

   The rules and conventions used in a communication on a network is called Protocols, i.e, rules and regulations to be followed by computers that are connected to a network.Basically a protocol is an agreement between communication device on how communication is to be proceed.A protocol defines a set of rules governing the exchange of data between computers.Only devices using the same protocol can communicate directly with each another.Computers using dissimilar protocols must transmit and receive through an intermediate interpretation device or program.

TCP/IP(Transmission control protocol/Internet protocol),  FTP(File transfer protocol) are examples of protocols .

Communication Medium

Communication Medium

   The communication medium is the medium through which two or more workstations are connected.In small network the communication medium used is 'Twisted pair cables or coaxial cables where copper conductors are used .Long distance networks are use other media such as micro wave transmission, etc.Very recently optical fibre cables that use light rays for data transmission and Wireless technologies such as blue tooth and Wireless Fidelity (Wi-Fi) are being used as communication medium.

Network Interface Card

Network Interface Card

    Every workstation has a Network Interface card or Unit (NIC), which is the hardware interface between a network and a workstation.It acts as an interpreter that helps to establish communication between a server and workstations.This is a microprocessor based device containing hardware and software, which supply the intelligence to control access and communication across network.The NIC provides transmission  and data control.i.e, it breaks up data into manageable units, translates the protocols of the workstation to that of the communication medium and supplies address recognition capabilities.The network interface unit is also called  as a network card or a network adapter.

Network interface Card

Servers

Servers

         A Server is a computer that facilitates the sharing of data, software and hardware resources.Servers perform a service to workstation on the network.The resources attached to a server such as drives and printers are shared by all users of the network.Some network use a small mini computers as the server.More than one server may be attached to a network with each server providing a different function.
Server may be one of two types:☻Dedicated server ☻Non-Dedicated server.


☺Dedicated Server : In large networks, a computer is  reserved for functions like sharing data, software and hardware resources.These computers often incorporate more powerful capabilities than user workstations.A dedicated server is unavailable for running user application and therefore increase system cost.It can support more features such as electronic mail service or multiple hard disks and provides faster system response.
In short these are only dedicated as a Server.

☺Non-dedicated servers : In smaller network, a computer can act as a server and node even while it controls the network.Such servers can facilitates resource sharing among network on a small scale.Since one computer works both as a server and a workstation it requires  more memory.Under light load, performance of a non-dedicated server may be slightly less then that of a workstation.Under heavy processing load, the individual user may find it difficult to work.Some network servers are capable of operating in both dedicated and non-dedicated mode, depending on users choice

    On a large network there can be several servers to share specific resources,A file server is to powerful computer that caters exclusively, file-related request such as storing files, controlling access privileges of each user or the amount of space reserved.A printer server is used to serve the printing requirements of the workstations on the network.A modem server is used to by a group of users to on the network to transmit long distance messages.

Workstation/Nodes

Workstation/Nodes

A workstation is any PC capable of supporting the hardware and software necessary to connect to a network.Every workstation can send or receive messages to or from other workstation or files server and share resources of the network.A computer becomes a workstation as soon as it is attached to a network.Workstation are also called Nodes.Nodes are one of the Network terminology.

Network Terminologies

Network Terminologies

For a user, a network is composed of computers and shared peripherals.However networks have several components such as computers which are either a workstation  or a Server, components such as media and network operating systems that perform some communication functions.

(Click on the topics for more info)

■ Workstation/Node

■ Server

■ Network Interface (card/unit)

■ Communication Medium

■ Protocols

■ Network Hub

■ Network Switch

Computer Network

Computer Network

        Computer Network is the combination of two or more computers connected through a communication system that allows exchange of information between computers.A computer network means interconnection collection of autonomous computers.The connection can be made using copper wire, lasers, micro waves or by using communication satellites.The old model of a single computer serving all of the organisational computational needs  
is replaced by one in which a large number of separate but interconnected computers do the job.


       Network can range in scope from a single location to almost global.Networks also usually involve telecommunication between PC's and are very important in office information systems.


Advantages of Networks


    A network can be useful for those frequent situation in which computer users wish to share information, secondary storage, peripheral devices or a database.For example a user may wish to send another user information in the form of a document , a graph or a spread sheet analysis.Without a network, the usual way to do this is to physically share a floppy disc.This cubersome  and the disc can become damaged and unreadable.Using a network the user can simply send the information over the network to the other user without having to store on a floppy disc.
      To say in a more general way the issue here is Resource sharing and the aim is to make all the programs, data and peripherals available to anyone on the network, without regard to the physical location of the resource and the user.This means that even if a user is several kilometer away from the data, it should not prevent him from using the data.
      All files can have copies on one or two computers, even if one of them is not available due to some hardware error, the pther copy can be used .This is called Reliability.In addition, the presence of multiple CPU means that even if one goes down the other may be able to take over the work with reduced performance.This is very important for banking, air traffic control and military applications.
     Small computers have a better price/performance ratio than large ones.A mainframe computers can be 10 times faster than a PC but it costs a thousand times than a PC.Therefore system designers build systems consisting of one PC per user, with data kept on one or more shared file servers.This saves money.
     Another advantage is that it is a powerful Communication medium.A network makes it easy for two or more people who lived apart to write a report together.When one person makes changes to an on-line document the other can view the changes immediately.This helps for co-operation among geographically spread groups of people.
    Networks are Scalable i.e, the system performance can be increased gradually as the work load grows by adding more processors.
   

Computer Softwares

"Computer Softwares are collection of programs designed for a particular task"

Softwares are classified into two :
1) System Software
2) Application Software

■ System softwares are again classified into two types(Click on 'System softwares' for more information)
■ Application Softwares are two types(Click on 'Application softwares' for more information)

Softwares give instructions to Hardwares for doing particular tasks.

Computer Hardware

What is a Hardware ?

" The parts of computer which can touch, see and feel are called Hardwares ".Hardwares and Softwares together form a Computer System.

Below are a list of Hardwares which is often seen in PC :

1) Motherboard

2)Monitor 

3)Keyboard

4)Mouse

5)PC case

6)Power supply

7)Hard Disc Drive[HDD]

8)Floppy Disc Drive[FDD]

9)Compact Disc Drive[CDD]

10)Speakers

11)Headset

12)Digital Video Disc Drive[DVD(D)]

13)Wires and Cables

Hardwares are instructed by Softwares for performing particular task.