Advantages and Limitations of Magnetic Disks

Advantages
  1. Unlike magnetic tapes, which support sequential access of data, magnetic disks support direct access of data. Hence, they are more suitable for a wider range of applications.
  2. Due to its random access property, magnetic disks are often used as online secondary storage devices, in which case they store data of multiple users of the computer system. A tape is not suitable for such type of usage, due to its sequential-access property.
  3. Magnetic disks are suitable for both online and offline storage of data. For example, Winchester disks and disk packs are often used as online secondary storage devices, whereas floppy disks and zip disks are used as offline secondary storage devices. In fact, the high-capacity Winchester disks have made it possible for today's most personal computer users to enjoy the convenience of having all data and software readily accessible at all times.
  4. Except for the fixed type Winchester disks, the storage capacity of other magnetic disks is virtually unlimited, because as many disks as required can be used for storing very large data sets.
  5. Due to their low cost and high data recording densities that magnetic dis, the cost per bit of storage is low for magnetic disks. An additional cost benefit is that magnetic disks can be erased and reused many times.
  6. Floppy disks and zip disks are compact and light in weight. Hence, they are easy to handle and store. Very large amount of data can be stored in a small storage space.
  7. Due to their compact size and light weight, floppy disks and zip disks are also easily portable from one place to another. They are often used for transferring data and programs from the one computer to another, which are not linked together.
  8. Any information desired from a disk storage can be accessed in a few milliseconds, because it is a direct access storage device. This is not possible in case of tape storage, which is a sequential access storage device.
  9. Data transfer rate for a magnetic disk system is normally higher than a tape system.
  10. Magnetic disks are less vulnerable to data corruption due to careless handling or unfavorable temperature and humidity conditions than magnetic tapes.
Limitations
  1. Although magnetic disks may be used for both types of application, for applications of the latter type, use of magnetic disks may be less efficient than magnetic tapes.
  2. It is more difficult to maintain the security of information stored on magnetic disks, which are used as shared, online secondary storage devices as compared to information stored on magnetic tapes or on other types of magnetic disks.
  3. For Winchester disks, a disk crash or drive failure often results in the loss of entire data stored on it. It is not easy to recover the lost data. Hence, suitable backup procedures are suggested for data stored on Winchester disks.
  4. Some types of magnetic disks, such as disk packs and Winchester disks, are not so easily portable like magnetic tapes.
  5. On a cost-per-bit basis, the cost of magnetic disks is low,  but the cost of magnetic tapes is even lower.
  6. They must be stored in a dust-free environment.
  7. Floppy disks, zip disks and disk packs should be labeled properly to prevent erasure of useful data by mistake.
Uses of Magnetic Disks
Magnetic disks are typically used for one or more of the following purposes:
  • For applications that are based on random data processing.
  • As a shared, online secondary storage device. Winchester disks and disk packs are often used for this purpose.
  • As a backup device for offline storage of data, so that if by accident, the data on an online storage device is corrupted, it can be retrieved from the backup storage. Floppy disks, zip disks, and disk packs are often used for this purpose.
  • Archiving of data which are not used frequently, but which may be used once in a while. Floppy disks, zip disks and disk packs are often used for this purpose.
  • Transferring of data and programs from one computer to another, which are not linked together. Floppy disks and zip disks are often used for this purpose.
  • Distribution of software by vendors. Originally sold software or software updates are often distributed by vendors on floppy disks and zip disks.























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