Storage Devices

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)