Note on Storage Devices

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External memory where data and instructions are stored in terms of magnetic spot using magnetic coated area is magnetic storage. Basically we have two types of magnetic storage these are magnetic tape and magnetic disk.

Magnetic Tape

It is a plastic ribbon, usually 0.5 inch or 0.25 inch wide and 50 to 2500 feet long, with magnetic coating (such as iron oxide) at one side. The tape ribbon is again covered inside reels or on a small cassette. Magnetic tape is the most popular storage medium for long time storage medium for long time storage. The tapes can also be erased and reused several times. Old data on the tape are automatically erased and overwrite as new data are recorded in the same area, just like in audio or video tape.

Magnetic Disk

Magnetic disk is most popular storage medium for direct access backup storage. It is thin, circular metal plate or flat rotating disc coated with magnetic material on both sides. Like tape, disks can also be erased and reused several times. The surface of disk is divided into a number of concentric circles, called tracks. Each of the track is further divided into sectors. Each sector typically contains 512 bytes and all are assigned with unique number called sector number. Popular disks are: hard drive and floppy disk.

Floppy disks:

These are also called diskettes. These are very thin and flexible, so called floppies. It is a thin, round, flexible plastic, coated with metallic oxide, encased in a square plastic or vinyl jacket cover protection. It comes in various sizes: 3.5 inches (Micro-floppy) and 5.25 inches (Mini-floppy) in a diameter. The advantage of diskette is that it is highly portable and very cheap as compared to other secondary storage devices. But now a day people are not using this storage frequently. The capacity of floppy disk varies from 1.44 MB to 2.0 MB.

Hard Disk:

These are most popular secondary storage devices. These are made up with set of rigid metal diskettes (mostly aluminum) which is permanently sealed in metal case for air-tight. Nowadays, removable hard disks have been introduced. We can use hard disks externally. The capacity of hard disk varies from some GB to 350 GB.

Optical storage:

Secondary storage where data are stored in terms of optical spot in optical disk. Due to the use of laser beam technology for recording/reading of data on the disk, these devices are called optical storage devices. This consists of rotating disk coated with thin metal or some other material that is highly reflective. The information stored in the disk can be accessed detecting the light. Optical disks have one long rack, starting at the outer edge and growth inwards to the center. The spiral track is best for reading large blocks of sequential data such as music.

Some useful technical terms

  1. The integration of input, processing & output unit. (Computer System)
  2. Board where all the vital components of computer are connected. (Mother board)
  3. A device that gives soft output. (monitor)
  4. A storage media that stores data for future uses. (Secondary storage)
  5. A device which converts analog signal to digital & vice-versa. (Modem)
  6. A device which can enter text, graphics etc. directly on the computer as input. (Scanner)
  7. The volatile memory of computer. (RAM)
  8. The processor built on a single chip. (Microprocessor)
  9. A device which allows providing data to the computer. (Input device)
  10. The electronic pathway on motherboard. (Bus)
  11. The device which is used to produce audio output. (Speaker)
  12. The device which supplies regular power to the computer even in black out. (UPS)
  13. The high speed memory kept in between CPU and main memory. (Cache memory)
  14. The par which make computer system. (Hardware)
  15. The section of CPU which performs mathematical calculations. (ALU)
  16. The output on printed form. (Hard copy output)
  17. The software stored in ROM chip. (Firmware)
  18. A device that stores electrical charges. (Capacitor)
  19. A program that makes devices of a computer functional. (Device driver)
  20. An interface or connection point where hardware devices are joined. (Port)
  21. The process of converting analog signal to digital form. (Digitizing)

  • Magnetic tape is the most popular storage medium for long time storage medium for long time storage.
  • Magnetic disk is most popular storage medium for direct access backup storage.
  • Floppy disks are very thin and flexible, so called floppies.
  • Hard disk are made up with set of rigid metal diskettes (mostly aluminum) which is permanently sealed in metal case for air-tight.
  • Due to the use of laser beam technology for recording/reading of data on the disk, these devices are called optical storage devices.
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Very Short Questions

The function of control unit is to control and coordinate all the functions inside the computer maintaining the supervisory work. The function of ALU is to perform all the mathematical and logical functions inside the computer.

Memory is a hardware which stores data instructions. The major classification of memory are:

  • Primary memory
  • Secondary memory (storage)

Secondary storage or memory is the auxiliary storage which hold the data and instructions for long term permanent purpose. They are:
i. Magnetic storage (Disk)
ii. Optical storage (Disk)
iii. Sequential storage

Magnetic disks are direct access storage devices which store data on magnet coated surface for permanently E.g. Hard disk, floppy disk etc.

Optical storage are the devices that use laser light technology to retrieve and store optically. They are CD-ROM, CD-RW, DVD-ROM etc.

The advantages of hard disk over floppy disk are:
1. Hard disk can store more data than floppy disk.
2. Data access time in hard disk is less than floppy disk.
3. Hard disk is stronger than floppy disk.

Sequential access storage devices are such types of secondary storage which searches
the data from the beginning of the disk. These types of devices are not commonly used
now days because data access is slower. E.g. Magnetic Tape.

A computer needs a secondary storage to store the information and programs for long term permanent purpose and makes them available or accessible when required.

Zip disk is a removable disk that stores the data magnetically and looks like an ordinary floppy disk but can store 70 times more data than a floppy disk.

Pen drive is a new generation flash memory device connected to USB ports which is small, portable and handy in nature. It is one of the easiest devices for data transfer.

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  • Floppy Disks are also called

    diskettes
    magnetic tape
    magnetic disk
    flapperies
  • A plastic ribbon, usually 0.5 inch or 0.25 inch wide and 50 to 2500 feet long, with magnetic coating (such as iron oxide) at one side is a

    magnetic disk
    optical storage
    floppy
    magnetic tape
  • External memory where data and instructions are stored in terms of magnetic spot using magnetic coated area is a

    magnetic storage
    optical storage
    magnetic output
    floppy
  • The storage element for a static RAM is the

    Flip-Flop
    magnet
    diode
    resister
  • The surface of disk is divided into a number of concentric circles are called

    tracks
    resister
    diode
    diskettes
  • Which is not a removable drive?

    super disk
    zip
    hard
    jaz
  • What is floppy disks?

    device that accepts data and instructions from the input devices.
    device that hold the programms and data.
    Read only memory
    small data storage device
  • What is Hard disk?

    common storage device
    device that holds files
    small data storage device
    device that transfer files
  • What is optical disks?

    both a and b.
    Can't say
    device produced using laser tehnology.
    device known as pendrives.
  • What is flash memory?

    Can't say
    device which store device upto 700 MB.
    device known by different common names as pen drives and memory card.
    both a and b.
  • Hard disk is considered as

    Flash storage
    Secondary storage
    Primary memory
    Main storage
  • Which of the following device stores data optically?

    Hard disk
    Pen drive
    CD-ROM
    Floppy disk
  • Which of the following is known as flash drive?

    Pen drive
    Zip Disk
    Cache memory
    Floppy disk
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