Data Storage

What is storage?

Storage refers to the media and methods used to keep

information available for later use. Some things will be

needed right away while other won't be needed for

extended periods of time. So different methods are

appropriate for different uses.

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Data Storage

Primary storage is main memory

The kinds of things that are stored in the main memory

are:

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Hard Discs

These are a common form of data storage in most computers.

• A typical computer would have a disk capacity of several gigabytes (GB).

• This would hold the operating system (eg Microsoft Windows) and applications (eg word processor and spreadsheets, databases, etc).

 

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Data StorageThis keeps track of what is currently being processed. It is volatile.  (Power off erases all data.)

For main memory, computers use RAM, or Random Access Memory. This uses memory chips and is the fastest but most expensive type of storage.

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Data Storage

Secondary storage

This is what is not currently being processed. This is the stuff ‘filed away’, but ready to be pulled out when needed.

It is non-volatile.  (power off does not erase.)  

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Data Storage

  So, secondary storage is where you put everything that is not being used right now.

 

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Examples of Secondary Storage

• Floppy disk

Floppy disk drivers can be found on most microcomputers and accept 3.5 in floppy discs. High density discs for a PC hold 1.44 Mb of data. Floppy discs are useful for transferring data between computers and for keeping a back-up of work files.

 

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Examples of Secondary Storage

• Compact discs

Most PCs now have CD-ROM drives included as standard. CD-ROMs are 12cm diameter plastic discs which can hold large quantities of data (650 Mb) in the form of text, sound, still pictures and video clips.

 

Over 700 high quality images

72 min of music

250000 pages of text 2 hours of video

19 hours of radio quality speech

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Examples of Secondary Storage

• Digital Video Discs(DVD) have a huge memory capacity. DVDs can store the equivalent of 26 CD-ROMs.  

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Examples of Secondary Storage

• Zip and Jaz drives

These are similar to floppy discs, in that individual discs are removable and portable, but they hold much larger amounts of data (between 100 Mb and 2 Gb).

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In this section

• you will become more familiar with different types of data storage

• you can use this knowledge to help you choose the right storage for your needs.

 

ICT Tools: Data Storage