1. By Molly

2.  Definition: refers to the copying of files/data to a different medium.  Why back up data? - To safe against loss of data. - To safe against damage caused by hackers. - To protect the originals against possible corruption or loss.

3.  This section briefly describes the two main methods of accessing data. It is important to understand three new term here: - Field - Record - File

4.  Serial access: start at the beginning of the file and access each record in turn until the required record is found.  Direct access: is used with magnetic disk, optical media and solid state media.

5.  Magnetic storage media Fixed/internal hard disk drive (HDD):store vast amounts of data, films. - Advantage: fast data, access, large memory. - Disadvantage: easily damaged, quite noisy Portable hard disk drives: used as backup systems and transfer data/file/data. - Advantage: fast, large memory. - Disadvantage: easily damaged, Magnetic tapes: used to store all the data - Advantage: less expensive, robust technology. - Disadvantage: very slow data access times

6. CD/DVD disk : can be designated as follows: - R-write once only - ROM – can only be read - RW- can be written to or read from many times CD-ROM and DVD-ROM : store music files, software, computer game - Advantage: large data, less expensive - Disadvantage: slower than hard disk CD-R and DVD-R : store data - Advantage: cheap - Disadvantage: not all CD/DVD can read CD-R/DVD-R

7. CD-RW and DVD-RW: record television programmes. - Advantage: can be written many times - Disadvantage: can be relatively expensive. DVD-RAM: used in camcorders to store movies. - Advantage: long life, fast access. - Disadvantage: not compatible, expensive. Blu-ray discs: home video consoles - Advantage: very large, fast. - Disadvantage: expensive, encryption problems. o The future of optical media: - On hard disk drive systems - In MP3 format on: computer, mobile, music player - Using “cloud” to store all files

8. Solid state drives (SDD): store data, used in laptop and desktop computer - Advantage: reliable, thin. Memory stick/pen drives: transporting files. - Advantage: very compact, robust. - Disadvantage: easy to lose. Flash memory cards: store photos - Advantage: very compact, easily to remove. - Disadvantage: expensive, low storage capacity