3. Comparisons of different back-up media

Media Size Example Advantages Disadvantages
CD-RW 650 mb Personal files or small systems

small and portable

fairly inexpensive

fast access to data

fragile - can snap or be scratched

relatively small storage capacity. could not be used to back up a network or large system

DVD-RW 4.7 Gb Personal files or small systems

fairly large storage capacity

inexpensive to purchase

most PCs contain a DVD RW-drive

do not work in CD drives

can be damaged by breaking or scratching

probably won't be large enough to back up a large system or network

Flash memory Up to 64 Gb Personal files or small systems

easily portable

hold large amount of data

more reliable than floppy disks and less easily damaged than CDs or DVDs

storage per megabyte is more expensive than many of the other media

they can be easily lost

the metal part can be easily snapped off

Magnetic Tape Over 100 Gb per tape Personal system or Network

relatively cheap per megabyte of storage

can store large amounts of data - usually the whole network

can be set to back-up overnight

serial access so can be quite slow to access data

need special equipment to record and read the data on the tape

External hard drive Up to 3000 Gb Personal data

robust storage device.

cheapest storage per megabyte than the other media

can back up a whole system or network

need a method of connecting the hard disk to the computer

fairly cumbersome to carry and store when compared to other media

Online storage Unlimited Personal data accessible from anywhere

could take a long time to download a large amount of data

May take a long time to upload the data in the first place.

security issues - need to be confident that your provider has adequate security procedures in place

can be an expensive method of backing up data.