Secondary Storage Devices (Edexcel IGCSE ICT)
Revision Note
Storage devices
What is a storage device?
A storage device is the hardware that reads from and writes to different storage medias
Storage devices are non-volatile secondary storage, that retain digital data within a computer system
They provide a means of storing, accessing, and retrieving data, which can include software applications, documents, images, videos, and more
There are 3 types of storage device:
Magnetic
Solid State
Optical
Magnetic storage
Magnetic storage is a type of non-volatile media that uses magnets (polarity) to store binary 0s and 1s
Advantages | Disadvantages |
|---|---|
Capacity - High storage | Durability - Moving parts can get damaged if dropped |
Cost - Low per gigabyte | Portability - Heavy & bulky making them less convenient for transport |
Speed - Moderate read/write access | Reliability - Prone to mechanical failure |
| Noise - Loud (spinning disks) |
Solid state storage
Solid state storage is a type of non-volatile media that uses electronic circuits to store binary 0s and 1s
Advantages | Disadvantages |
|---|---|
Capacity - Medium/high storage | Cost - Very high per gigabyte |
Speed - Very fast read/write access | Reliability - Limited read/write cycles |
Durability - No moving parts |
|
Portability - Small and no moving parts |
|
Noise - Silent |
|
Optical storage
Optical storage is a type of non-volatile media that uses lasers to burn the surface of a disk, creating pits and lands suitable for storing binary 0s and 1s
Advantages | Disadvantages |
|---|---|
Cost - Very low per gigabyte | Capacity - Very low |
Durability - No moving parts | Speed - Very slow read/write access |
Portability - Small and no moving parts | Reliability - Prone to scratches |
Noise - Silent |
|
Capacity of storage
What is capacity of storage?
Capacity of storage describe the amounts of binary digits that can be stored on a digital device
These are the units you need to know for this IGCSE:
Unit | Symbol | Value |
|---|---|---|
Bit | b | 1 or 0 |
Nibble |
| 4 b |
Byte | B | 8 b |
Kibibyte | KiB | 1024 B (210) |
Mebibyte | MiB | 1,048,576 KB (220) |
Gibibyte | GiB | 1,073,741,824 MB (230) |
Tebibyte | TiB | 1,099,511,626,776GB (240) |
Megabyte vs Mebibyte
1 kibibyte = 1024 bits - binary prefixes (to the power of 2)
1 kilobyte = 1000 bits - decimal prefixes (to the power of 10)
Worked Example
Explain one benefit of using solid state storage with a smartphone
[2]
Answer
An explanation such as:
Data (transfer) will not be negatively affected by movement / less risk of damage to the drive [1]...
...because solid state storage does not use moving parts [1]
OR
Smartphones are portable [1]...
...because solid state storage takes up less space / has no moving parts [1]
OR
Longer battery life [1]...
...because solid state storage uses less power [1]
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