• Originally, data is the plural of the Latin word datum, from dare, meaning ‘give’.
  • The word ‘Data’ refers to any raw collection of facts, figures and statistics. 
  • In general, data in computer is any set of characters that is gathered and translated for some purpose, usually analysis. It can be any characters, including text and numbers, symbols, pictures, sound, or video. 
  • Data is raw, plain, unorganized facts that need to be processed.
  • Data is any sequence of one or more symbols given meaning by specific act(s) of interpretation.
  • Data can be something simple and seemingly random and useless until it is organized.


  • When data is processed, organized, structured or presented in a given context so as to make it useful, it is called information. 
  • Data themselves are fairly useless, but when these data are interpreted and processed to determine its true meaning, they become useful and can be named as Information.
  • Information is important in the decision-making and problem-solving processes, and without the right information, an organization make mistakes during processing.


  • bit (short for binary digit) is the smallest unit of data in a computer.
  • bit has a single binary value, either 0 or 1 i.e. A bit stores just a 0 or 1.
  • A bit is atomic and is the smallest unit of storage.
  • It’s a single unit of information that can have a value of either 0 or 1 (off or on, false or true, low or high).
  • A bit is the smallest unit of computer measurement which means nothing comes before a bit.
  • Bit is used to represent the color also – an 8-bit color would be 2^8 = 256 colors. 
  • In a chip: electric charge = 0/1
  • In a hard drive: spots of North/South magnetism = 0/1


  • A byte is composed of eight consecutive bits.
  • It is unit of information storage.
  • Bits – Bytes Conversion
    • 1 bit = 0/1
    • 4 bits= half byte = 1 nibble.
    • 1 byte = 8 bits = 1 character.
    • 1 kilobyte (K/Kb) = 2^10 bits = 1,024 bytes= About 1 thousand bytes.
    • 1 megabyte (M/MB) = 2^20 bits = 1,048,576 bytes= About 1 million bytes = 1024 KB.
    • 1 gigabyte (G/GB) = 2^30 bits = 1,073,741,824 bytes= About 1 billion bytes = 1024 MB.
    • 1 terabyte (T/TB) = 2^40 bits = 1,099,511,627,776 bytes= About 1 trillion bytes = 1024 GB.
    • 1 petabyte (P/PB) = 2^50 bits = 1,125,899,906,842,624 bytes
    • 1 exabyte (E/EB) = 2^60 bits = 1,152,921,504,606,846,976 bytes
    • zettabyte (Z/ZB)= 2^70 bits = 1,180,591,620,717,411,303,424 bytes
    • 1 yottabyte (Y/YB) = 2^80 bits = 1,208,925,819,614,629,174,706,176 bytes

Word/Word Length

  • The fundamental data types of the Intel Architecture are bytes, words, doublewords, and quadwords.
  • A byte is eight bits, a word is 2 bytes (16 bits), a doubleword is 4 bytes (32 bits), and a quadword is 8 bytes (64 bits).

Bit Processor

  • With early computer processors (e.g., 8088 and 80286) the processors were 16-bit Processors, which means the processor were capable of working with 16-bit binary numbers (decimal number up to 65,535). Any value larger than bit processor, the computer would need to break up the number into smaller pieces.
  • 32-bit Processor, which are capable of processing up to 32-bit binary numbers (decimal number up to 4,294,967,295).
  • Today’s computers are 64-bit Processor, which are capable of up to 64-bit binary numbers (decimal number over 18 quintillion). 

    Configuration of a Computer –

    • Configuration of a PC usually mean the technical specification/details of the System.
    • In this specification details generally we include speed of the processor, RAM, Hard-Disk Drive, Video card, etc.
    • The configuration of one computer may vary from others. Generally configuration of a computer depends on the user requirement/use.
    • Processor plays major role in computer configuration. Processor power/capacity depends on clock speed of the processor.
    • Before purchasing a PC we should be aware about the different components of a PC and its typical configuration so that we can make a suitable choice.
    • Many software require that computer must have some minimum requirements so that the software can run properly on that system, hence we need to check the configuration of the system.

    Clock Speed

    • Processor power/capacity depends on clock speed of the processor.
    • Clock speed is the speed at which a microprocessor executes instructions.
    • Clock speeds are measured in megahertz (MHz) (also known as, millions of cycles per second) or Gigahertz (GHZ) normally. More the value of Mhz/Ghz, more the processing power of a processor.
    • One clock cycle is the time it takes to perform one instruction. Processor will be faster if the clock cycle is shorter and vice versa.
    • The speed of a processor is directly related to the clock speed which is the speed at which a microprocessor executes instructions.
    • Generally a processor or cpu is said to be same but the CPU contains at least one processor inside it, which is the actual chip inside the CPU that performs calculations.
    • There are two primary manufacturers of computer microprocessors in the world. Intel and Advanced Micro Devices (AMD) that lead the market in terms of speed and quality. Intel’s desktop CPUs include Celeron, Pentium and Core and AMD’s desktop processors include Sempron, Athlon and Phenom.

    Connecting Port/Port 

    • Ports are the interfaces through which computers communicate with the system component and external devices such as printers, modems, joysticks and terminals.
    • Port is a connecting socket, outside the system into which different types of cables are plugged.
    • It is a specific place from which other devices can be physically connected.
    • I/O ports are the most common interfaces through which computers communicate with external devices such as printers, modems, joysticks and terminals.
    • There are many types of ports used in computer system. Some of them are –
      • Parallel Port –
        • A parallel port transmits 8 bits of a byte of data in parallel.
        • A parallel port transmits an entire byte at a time, it operates I/O devices at a relatively high speed.
        • Various peripheral devices can be connected through parallel port, which is a parallel communication physical interface.
        • It is used for transmitting fast data over short distances.
        • A Parallel port is primarily used to connect printers to a computer and hence it is often called a printer port.
      • Serial Port –
        • Serial Port transmits one bit of data from a byte, one at a time as a single stream of bits.
        • It is meant for transmitting slow data over long distances.
        • It is a serial communication physical interface which transmits one bit at a time.
        • Communication over a phone line is an example of serial communication.
        • Dial-up modems and serial mice use serial ports.
      • USB (Universal Serial Bus) Port –
        • A USB Port can connect up to 127 peripheral devices such as a digital camera, digital speakers, scanners, speakers etc. through this port.
        • It permits Plug and Play – configuring of expansion cards and peripheral devices as and when they are installed.
      • SCSI (Small Computer System Interface) Port –
        • SCSI Port allows data to be transmitted in a daisy chain to up to 7 devices at a speed higher (32 bits at a time) than those possible with serial and parallel ports.
        • It is a fast data transmitting device and is used to connect HDD, CD ROM drives and scanners with the computer system.

    Device Drivers 

    • It is a group of files that enable one or more hardware devices to communicate with the computer’s operating system.
    • A driver software is a small program that allows the operating system to communicate with the peripheral devices.
    • Without drivers, the computer would not be able to send and receive data correctly to hardware devices, such as a printer, camera, mobiles etc.
    • Device drivers are shared computer programs that provide an interface between the hardware devices and operating system or other higher level programs. We need a specific software program to control each hardware device attached to the computer. It is very tedious to make any piece of hardware work.
    • Device drivers are hardware dependent and operating system specific.
    • They allow to add and remove devices conveniently from your computer system without changing any of the applications using that device.
    • Common hardware components that require drivers in computers are: Keyboards, Mouse, Printers, graphics cards, sound cards, card readers, CD/ DVD drives, Network cards, Image Scanners etc.
    • There are various types of device drivers such as I/O Drivers for I/O devices (such as keyboards, mice, CD/DVD drives, controllers, printers, graphics cards and ports)  virtual device drivers (VxD), which are device driver components that enable direct communication between a hardware device and an application.

    Electronic Circuit  

    • An electronic circuit is made from different electronic components such as transistors, resistors, capacitors and diodes, which are connected to each other in different ways to achieve some objectives.
    • It is an unbroken loop of conductive material that allows electrons to flow continuously.
    • If a circuit is “broken”, its conductive elements will no longer form a complete path and continuous electron flow cannot occur. 
    • For example resistors are used, among other things, to control the volume in television sets or radios. The capacitor collects electricity and releases it all in one quick burst. The diode stops electricity under some conditions and allows it to pass only when these conditions change. Diode is used in, photocells where a light beam that is broken triggers the diode to stop electricity from flowing through it.
    • The flashlight is an example of electric circuits.
    • It contains electrical energy (dry cells) as a source, a load (the bulb) which changes the electrical energy into light and a switch to control the energy delivered to the load.)

    Video Card 

    • A video card is an expansion card , which is used to produce output images to a display in a monitor.
    • Its main purpose is to generate graphical information.
    • It is responsible for rendering the image on the monitor of a PC .
    • It is also known as video adapter, display adapter or graphics card.
    • A video card should be capable of displaying the best resolution supported by the monitor of the system.
    • These days high performance video cards are available for gaming purposes which requires very high resolution.
    • Video card consists of a circuit board which holds several components such as graphics processing unit (GPU), video memory, video BIOS etc.
    • Video graphics array (VGA), Digital visual interface, high definition multimedia port etc are some of the common connection points used between video card and display.
    • Now-a-days, high performance video cards are available, which has higher visual capability.
    • With increasingly popularity of computer games video cards became one of the most important parts of a computer.
    • One disadvantage of this high performance video card is that consume high power.
    • The amount of video memory in video card is one of the main considerations while opting for a video card.
    • Advanced graphics port (AGP) and PCI-Express are the two commonly slots available which is used to connect a video card.

    Screen Resolution

    • The Screen Resolution of a monitor means the number of pixels per inch appearing on its surface.
    • In general the greater the number of pixels the sharper is the images.
    • CRTs provide variability in resolution.
    • LCDs monitor have a fixed resolution.

    System Restore

    • System restore roll backs system files, registry keys etc in case of system malfunction or
      failure, for later use.
    • System restore is a facility available with modern windows operating system like Windows XP, Windows vista, Windows ME, Windows 7.
    • System restore backs up system files such as .dll, .exe etc and saves it for later use.
    • System restore helps us to restore computer’s system files to an earlier state.
    • Sometimes it happens that while installing a program or during use of any other software in the computer, there may some problem occurs and the system starts malfunctioning. One way to get rid of such type of problem is to re-install the software or drivers. But if uninstalling the software doesn’t fix the problem then we can restore the computer to an earlier date when the system was working properly.
    • Restore points are used for this purpose which contains information related to registry settings and system information.
    • It is important to note that the system restore is not able to take back ups of personal files such as images, e-mails, documents etc. so if these personal files got accidentally deleted or lost it cant be restored using system restore. So it’s a better practice to take back ups of your personal file regularly.
    • Steps to use System Restore in window XP Professional – Follow these steps to perform restore on our PC:
      1. Click on Start button, select All Programs, from there choose Accessories, click on System Tools, and then click System Restore. System Restore starts.
      2. On the Welcome to System Restore page, click Restore my computer to an earlier time (if it is not already selected), and then click Next.
      3. On the Select a Restore Point page, click the most recent system restore point in the On this list, click a restore point list, and then click Next.
      4. On the Confirm Restore Point Selection page, click Next. System Restore restores the previous Windows XP configuration, and then restarts the computer.
      5. Log on to the computer as Administrator. The System Restore Restoration Complete page is displayed.
      6. Click OK.

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