1.2 - Storage Media
Exam Board:
OCR
Specification:
2016 - Unit 2
Data can be stored on a variety of storage media, each with its own benefits and drawbacks.
Magnetic Storage
Optical Storage
A magnetic hard disk drive (HDD) is the most common form of secondary storage within desktop computers. A read/write head moves nanometres above the disk platter and uses the magnetic field of the platter to read or edit data. Hard disk drives can also be external and connected through a USB port.
An obsolete (no longer used) type of magnetic storage is a floppy disk but these have been replaced by solid state devices such as USB sticks which are much faster and have a much higher capacity.
Another type of magnetic storage that is still used is magnetic tape. Magnetic tape has a high storage capacity but data has to be accessed in order (serial access) so it is generally only used by companies to back up or archive large amounts of data.
Optical storage uses a laser to project beams of light onto a spinning disc, allowing it to read data from a CD, DVD or Blu-Ray.
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This makes optical storage the slowest of the four types of secondary storage.
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Disc drives are traditionally internal but external disc drives can be bought for devices like laptops.
Magnetic Storage Characteristics:
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✓ - Large CAPACITY and cheaper per gigabyte than solid state.
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X - Not DURABLE and not very PORTABLE when powered on because moving it can damage the device.
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✓ - Relatively quick ACCESS SPEED but slower than Solid State.​
Optical Storage Characteristics:
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X - Low CAPACITY: 700 MB (CD), 4.7 GB (DVD), 25 GB (Blu-ray).
X - Not DURABLE because discs are very fragile and can break or scratch easily.
✓ - Discs are thin and very PORTABLE.
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X - Optical discs have the Slowest ACCESS SPEED.
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Magnetic Disks are spelled with a k and Optical Discs have a c.
Solid State Storage
Paper Storage
There are no moving parts in solid state storage.
SSDs (Solid State Drives) are replacing magnetic HDDs (Hard DIsk Drives) in modern computers and video game consoles because they are generally quieter, faster and use less power. SSDs can also be external.
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A USB flash drive (USB stick) is another type of solid state storage that is used to transport files easily because of its small size.
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Memory cards, like the SD card in a digital camera or a Micro SD card in a smartphone, are another example of solid state storage.
Paper storage includes printed or hand-written documents, notes, forms, schedules and maps. Paper is relatively inexpensive in small quantities but it can take up a lot of space compared to small devices like USB sticks.
Producing paper is environmentally damaging and requires physical security methods to keep safe.
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Paper, such as a timetable, can be written on if times change and easily carried on a person. However, paper in the form of an essay must be re-printed to add changes.
Solid State Characteristics:
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✓ - High CAPACITY but more expensive per gigabyte than magnetic.
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✓ - Usually DURABLE but cheap USB sticks can snap or break.
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✓ - The small size of USB sticks and memory cards mean they are very PORTABLE and can fit easily in a bag or pocket.
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✓ - Solid State storage has the fastest ACCESS SPEED because they contain no moving parts.
Paper Storage Characteristics:
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X - Low CAPACITY as each page can only hold a certain amount of information. Paper also takes up physical space.
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X - Poor DURABILITY as paper can easily tear and become damaged in rain.
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✓ / X - PORTABILITY varies as single sheets of paper can be easily folded and placed in a pocket. However, large stacks of paper can be difficult and expensive to transport.
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X - Paper's ACCESS SPEED, in terms of searching for a specific item, is slow, especially if the paper storage has not been organised efficiently.
Questo's Questions
1.2 - Storage Media:
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1. State 3 examples of each type of storage media. For example, a CD for optical storage. [3 each]
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2. Compare each type of storage media in terms of capacity, durability, portability and access speed. You may decide to do this as a table or poster. [16]
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3. Identify the most suitable device (not the media) and justify its suitability for the following scenarios:
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a. Backing up a large database at the end of each day. [5]
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b. Keeping a copy of a cleaning schedule for hotel staff. [5]
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c. Making copies of a promotional video to hand out to audience members at a dancing event. [5]