Secondary Storage Devices (Edexcel IGCSE Ict)
Storage devices
Spec point —
1.5.3
What is a storage device?
-
A storage device is the hardware that reads from and writes to different storage medias
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Storage devices are non-volatile secondary storage, that retain digital data within a computer system
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They provide a means of storing, accessing, and retrieving data, which can include software applications, documents, images, videos, and more
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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
Spec point —
1.5.6
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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