Storage (Cambridge International IGCSE ICT)
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
Exam Hint
- The term ‘backing storage’ is often used interchangeably with ‘storage device’
- Always remember: RAM is primary memory, but everything else that stores data permanently is backing storage
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 |
Backing storage
-
Backing storage (also called secondary storage) refers to any non-volatile storage device
-
Used to store data and programs when they are not actively being used in RAM
-
It is essential for long-term data storage
-
Common types of backing storage include:
- Hard disk drives (HDDs)
- Solid state drives (SSDs)
- Optical disks (CDs, DVDs, Blu-ray)
- Portable storage devices like USB sticks and external drives
Storage Media
What is storage media?
- Storage media is the physical media that holds non-volatile data
- Storage devices have a specific read/write mechanism built in to interact with a particular storage media
- For example, magnetic tape media is read by a magnetic storage device
Exam Hint
- Try not to get confused between storage devices and storage media.
- Think of storage devices as large pieces of furniture in your home e.g. bookshelf, chest of drawers etc.
- Storage media is what you store in the furniture e.g. books on the shelf or clothes in the drawers
- Storage media all hold data, but the way it stores/accesses it can be very different, so just like you wouldn't store clothes on a bookshelf, you need to pair the correct storage device and storage media
Example storage media
| Media | Use | Advantages | Disadvantages | Storage Devices |
|---|---|---|---|---|
| Hard disk drive (HDD) | General-purpose storage in computers and servers | Large storage capacity (5TB), relatively fast | Moving parts, vulnerable to physical damage | Magnetic |
| Portable hard disk drive | External storage for data transfer and backup | Portable (5TB), large storage capacity | Slower than SSDs, vulnerable to physical damage | Magnetic |
| Magnetic tape | Backup and archiving, especially for large volumes of data | High storage capacity (10TB), low cost | Slow access time, sequential access | Magnetic |
| CD | Audio and data storage, software distribution | Affordable, widely compatible | Low capacity (700MB), susceptible to scratches | Optical |
| DVD | Higher capacity storage for data, video, and software distribution | Higher capacity than CD (8.5GB), affordable | Susceptible to scratches, lower capacity than Blu-ray | Optical |
| Blu-ray | High-definition video and high capacity data storage | High capacity (50GB), high-resolution video storage | More expensive, and requires specific hardware | Optical |
| Solid state drive (SSD) | Fast internal storage for modern computers | Fast access time, no moving parts, high capacity (30TB) | More expensive, limited write cycles | Solid state |
| Portable solid state drive | External storage for fast data transfer and backup | Fast access time, portable, no moving parts, high capacity (2TB) | More expensive, limited write cycles | Solid state |
| USB memory stick | Portable data storage and transfer for various devices | Small size, fast read/write speeds, high capacity (1TB) | Limited capacity compared to other storage devices | Solid state |
| Flash memory (SD/XD) | Removable memory cards used in smartphones/digital cameras | Very small, durable, large capacities | Easy to lose due to size, expensive per GB compared to HDD | Solid state |
Worked Example A program collects a large amount of data and this could be stored using either a fixed solid-state drive (SSD) or cloud storage.
a. Describe four advantages to the school of using cloud storage rather than using the SSD
[4]
Answer
Four of:
Final answer: The cloud has greater storage capacity [1]
Final answer: The data could be sent directly to/from the cloud from any computer/device [1]
Final answer: Storage capacity can be increased without adding additional physical devices [1]
Final answer: Many people can share the data [1]
Final answer: The school would only pay for the storage used [1]
Final answer: There is an automatic backup of data [1]
b. Describe three disadvantages to the school of using cloud storage rather than using the SSD
[3]
Answer
Three of:
Final answer: More security issues as multiple copies of the data are stored [1]
Final answer: The school loses control over the storage of the data [1]
Final answer: Cloud storage has an ongoing cost [1]
Final answer: Users must have a reliable internet connection to store data [1]
Final answer: Users must have an internet connection to access data [1]
Was this revision note helpful?
Build on this topic