You should make it a habit to backup your files. In the case that data on your computer or server is lost, damaged, or destroyed, you can recover what you need from backups. You can save your backups locally or in remote locations on servers or on physical devices. Backup media includes external hard drives, compact disks (CDs), and digital video disks (DVDs). You can also save data on tapes.
A compact disc rewritable (CDRW) is an optical storage medium. It is reliable and can store a small amount of data including word processing documents, images, and spreadsheets. There are two types of compact disk. A compact disc recordable (CDR) can be written on once and a compact disc rewritable (CDRW) can be erased. CDs hold about 700 MB of data or 80 minutes of audio. These devices are inexpensive and ideal for short term and small scale data storage.
A digital versatile disc or digital video disc (DVD) can be used to store data that needs frequent access and few changes. You can use DVDs to back up small and portable files, such as your MP3 collection. DVDs can store up to 10 GB of data. DVDs come in two formats: DVD+R and DVD+RW. You can write DVDs at speeds up to 24x.
Using a tape drive, you can back up entire hard drives, operating systems, applications, servers, and files at once. They are cheap and stable and last for a long time, if kept away from magnets. A tape drive reads and writes data to a magnetic strip. Although you can store large amounts of data for long amounts of time, there are drawbacks to using tapes. For one, you must access data in a sequence, and you cannot select a file at random. You must restore all items in a back up to restore one file. Another drawback is that the average seek time is long compared to hard drives.
Disks are generally identifiable by their flat, square shape. These are relatively outdated, and many computers no longer support disks. In any case, they are convenient for small files such as presentations, spreadsheets, and financial documents, especially if you are using an older computer. Disk capacity tends to be small at 1.44 MB. Disks provide convenient options for storage, but they are susceptible to environmental conditions such as dust.
Universal Serial Bus (USB) keys provide compact and portable options for data storage. USB keys can be used to store files including music, presentations, and spreadsheets. You can also use USB keys for continuous backup. You can insert the USB key in the morning and leave it in all day to make sure that the information is constantly updating.