Storage devices
Secondary storage refers to any device that can store data, in addition to main memory. Secondary storage devices are and are typically high capacity, portable or both.
Factors affecting the choice of a secondary storage device include:
- speed (how quickly data can be accessed)
- cost per storage unit (i.e. price per gigabyte or megabyte)
- durability (toughness)
- portability (how easy it is to move it from one computer to another)
Uses, advantages and disadvantages of storage media:
| Storage device | Advantages | Disadvantages | Characteristics / Typical uses |
| Magnetic storage: Hard Disc Drive (HDD) | Relatively cheap per unit of storage. Fast access and retrieval times compared to other storage devices. | Can be easily damaged, will slow down and eventually break over time. Slower access than Solid State Drives. | The main storage device in most computer systems. |
| Optical storage: Blu-ray disk | Can hold a lot more data than a standard DVD, meaning it can store movies with better picture and sound quality. Portable. | More expensive than DVDs. Requires a Blu-ray player. Can lose data when scratched. | A laser reads from and writes to Blu-ray disks. Used to store HD movies and other HD recordings. |
| Electrical storage: Solid State Storage Devices (SSD) | Very compact in size and therefore very portable. High speed of data transfer and low power consumption. | Considerably more expensive per unit than magnetic storage. More vulnerable to abrupt power loss and electro-magnetic fields. | USB flash drives and solid state hard drives have replaced the traditional HDD in some new computers. Memory cards are used as a convenient and portable removable storage medium. |
| Storage device | Magnetic storage: Hard Disc Drive (HDD) |
|---|---|
| Advantages | Relatively cheap per unit of storage. Fast access and retrieval times compared to other storage devices. |
| Disadvantages | Can be easily damaged, will slow down and eventually break over time. Slower access than Solid State Drives. |
| Characteristics / Typical uses | The main storage device in most computer systems. |
| Storage device | Optical storage: Blu-ray disk |
|---|---|
| Advantages | Can hold a lot more data than a standard DVD, meaning it can store movies with better picture and sound quality. Portable. |
| Disadvantages | More expensive than DVDs. Requires a Blu-ray player. Can lose data when scratched. |
| Characteristics / Typical uses | A laser reads from and writes to Blu-ray disks. Used to store HD movies and other HD recordings. |
| Storage device | Electrical storage: Solid State Storage Devices (SSD) |
|---|---|
| Advantages | Very compact in size and therefore very portable. High speed of data transfer and low power consumption. |
| Disadvantages | Considerably more expensive per unit than magnetic storage. More vulnerable to abrupt power loss and electro-magnetic fields. |
| Characteristics / Typical uses | USB flash drives and solid state hard drives have replaced the traditional HDD in some new computers. Memory cards are used as a convenient and portable removable storage medium. |
