unit 3=storage devices

unit 3=storage devices

1. fixed internal hard disk

   • Fixed internal disk drive (HDD) It is used to store the operatig system, systems software and working data/files. Also, it can be used in real-tyme systems (for example, robots), and in online systems (for example, booking airline tickets). Their advantages are, it has a very fast data transfer rate and fast access times to data, and also it has a very large memory capacity. And some disadvantages, it can be easily damaged if the correct shut down procedure isn't carried out; this can lead to a head crash which would result in a loss of data, also, it has many moving parts when compared to a solid state drive, and finally its read/write operation can be quite noisy compared to SSDs.Fixed internal disk drive (HDD) It is used to store the operatig system, systems software and working data/files. Also, it can be used in real-tyme systems (for example, robots), and in online systems (for example, booking airline tickets). Their advantages are, it has a very fast data transfer rate and fast

2. Portable hard disk drives It is used as backup systems to prevent loss of data, and also they can be used to transfer data/files/software between computers. Some advantages, the data access time and data transfer rate is very fast, they have a large memory capacity and they can be used as a method of tranferring informations between computers. And some disadvantages, they can be easily damaged if dropped or subjected to a strong magnetic field.

3. Megnetic tapes It is used in apps where batch processing is used, for example, clearing bank cheques; in these applications there is no need for any specific processing order and speed of data access is not essential, it is also used as a backup media since all the data needs to be stored, and it's used in long-term archiving of data; they have huge data storage capacities. As advantages, they are generally less expensive (per bute) than the equivalent hard disk, it i a very robust technology and also the data transfer rate is actually fast. And some disadvantages, it has very slow data access times, when updating, another tape is needed to store the final update version, and finally, they are affected by magnetic fields; a strong magnet can corrupt data stored on the tape.

4. . CD ROM and DVD ROM CD-ROMs are used to store music files, software, computer games and reference software (such as an encyclopaedia), DVD-ROMs have much larger storage and are used to store films, computer sata and ever-more sophisticated computer/arcade games, and CD-ROMs and DVD-ROMs are used in applications where there is a real need to prevent the deletion or overwriting of important data. Some good aspects are, they hold far more data than floppy disks, and they're less expensive than hard disk drive systems. A disadvantage, the data transfer rate/data access time is slower than for hard disks.

5. . Memory sticks Memory sticks are used for transporting files between computers or used as a backup store, and also used as a security device to prevent software piracy. Some advantages, it is very robust and very compact, it doesn’t need additional software to work on most computers and they´re not affected by magnetic fields. And some bad aspects include, it can´t write-protect the data, it is easy to lose and the user needs to be very careful when removing a memory stick from a computer.

6. Flash memory card It is a device used for storing photos on digital cameras, used as a mobile phone memory cards, also used in MP3 players to store music files and used as a backup store in hand-hels computer devices. Good things about it, it is very compact and can be easily removed and used in another device or for transferring photos directly to a computer or printer, and also, since they´re solid state memories, they are very robust. And some disadvantages are, it is expensive, it has a finite life regarding and also it has a lower storage capacity than hard disks.