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Objective of this lesson. Understand data archives and back-ups. Imagine a library. There are many different shelves Each shelf contains many books or CDs. Each book/CD is labeled with type and numbers (Eg. Zoology, 0001 to 0029) The library is very organised.
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Objective of this lesson Understand data archives and back-ups
Imagine a library • There are many different shelves • Each shelf contains many books or CDs. • Each book/CD is labeled with type and numbers (Eg. Zoology, 0001 to 0029) • The library is very organised.
A data archive • A data archive is like a library • Each folder is like a shelf • The folder contains many files • Each file is like a book on the shelf.
Summary of a data archive • An archive is very well organised so that people can find information easily. • We do not delete older archives because they are never out-dated. The collection keeps growing with new archives. • The storage media used for archive must be durable. Eg. Magneto-optical (MO) Disk. • An archive contains years of information which people can access. • We should protect archives from being modified because the information must be reliable.
Definition Archive is a copy of data on durable storage media for long term storage and later access.
Definition A back-up data is an extra copy of data that is important to you. It is to protect ourselves from losing this data.
Summary of a back-up • A back-up may not be well organised because it is a quick way to protect ourselves even if we lose the original data. • We delete older back-ups because they are out-dated. • The storage media used for back-up must have high performance speed. Eg. Magnetic tape.
Difference between an archive and a back-up • An archive is very well organised so that people can find information easily. • We do not delete older archives because they are never out-dated. The collection keeps growing with new archives. • The storage media used for archive must be durable. Eg. Magneto-optical (MO) Disk. • A back-up may not be well organised because it is a quick way to protect ourselves even if we lose the original data. • We delete older back-ups because they are out-dated. • The storage media used for back-up must have high performance speed. Eg. Magnetic tape.