Types of Secondary Storage

• Secondary storage is needed to write, rewrite, store, and retrieve data when the computer is switched off
• Primary memory (RAM) allows writing and storing data but is volatile, while ROM allows storing data without power but cannot be written to
• Secondary storage is used to rewrite data when needed and store data when the computer has no power
• Magnetic storage uses magnetisation patterns in a magnetisable material to store data, where magnetised points represent '1' and demagnetised points represent '0'
• Optical storage consists of 'marks' arranged in patterns, with laser burning 'pits' into the surface for writing and reflecting light for reading
• Solid state storage (Flash) traps electrons in specific orders using circuitry, with different electron arrangements representing data
• Magnetic storage is used in desktop computers for large files, programs, and operating systems, with a capacity of 750GB to 3TB, high read/write speeds, and low cost
• Optical storage is used for small media files and documents, with capacities of 650MB for CDs and 4.37GB for DVDs, moderate read/write speeds, and very cheap cost
• Solid state/Flash storage is used in desktop computers, laptops, and tablets for large files and programs, with capacities of 64GB to 480GB, super-fast read/write speeds, and very expensive cost
• Flash memory sticks are used for backing up or transferring documents and small media files, with capacities of 1GB to 64GB, super-fast read/write speeds, and expensive cost
• Network Attached Storage (NAS) drives are standalone external hard drives in a network, with capacities of 750GB to 3TB, high read/write speeds, and can be cheap or expensive depending on the type of disk used
• Cloud storage is used to store documents and media files online, with unlimited capacity, speed depending on network bandwidth, virtual portability, and can be expensive depending on the service