ICTFS 01: Fundamentals of ICT - Topic 6: Secondary Storage

Study Notes

Secondary storage devices save data permanently and are non-volatile.
Data is retained even after the computer is turned off.
Secondary storage devices have a capacity (number of bytes that can be stored) and an access speed (time required to retrieve data).

Magnetic storage uses magnetism to store data.
Hard Disk Drive (HDD) uses magnetic particles to store data on inflexible, rigid metallic circular platters.
HDD consists of two main elements: platter and actuator arm.
Data is stored and organized using tracks and sectors.
HDD retrieves data by reading magnetic charges on the disk.
Density refers to how tightly charges can be packed next to each other on the disk.
HDD can be internal (fixed disk) or external (portable).
Hard disk is sensitive and can be damaged by dust, fingerprints, or human hair, leading to a head crash.

Disk caching improves processing by acting as a temporary high-speed data holding area between secondary storage device and CPU.
Redundant Arrays of Inexpensive Disks (RAID) improve performance by expanding external storage, improving access speed, and providing reliable storage.
File compression and decompression programs increase storage capacity by reducing the amount of space required to store data and programs.

Floppy disk is a removable storage device used for transferring small amounts of data between computers or for backing up small files.
Access times are slow, and capacity is low (1.44MB).

Zip disk is a high-capacity alternative to floppy disk.
Zip disk has a larger capacity (100MB, 250MB, or 750MB) and is faster than floppy disk.

SuperDisk is a high-speed and high-capacity alternative to floppy disk.
SuperDisk has a larger capacity (120MB and later 240MB) and is faster than Zip disk.

Magnetic tape is an old technology used for audio and video recording.
Types of magnetic tape include reel-to-reel, compact cassette, RCA tape, and others.

Solid-state storage devices have no moving mechanical parts, making them faster than traditional electromechanical storage.
Solid-state storage is more expensive than traditional storage.
Solid-state storage is designed to be connected like a hard disk but contains solid-state memory instead of magnetic disks.
Advantages of solid-state storage include faster access time, faster transfer rates, less heat generation, and lower power consumption.

Memory cards are small solid-state storage devices used in portable devices.
Types of memory cards include compact flash, secure digital, microSD, and others.

Pen drives are also known as flash drives and can transfer files from one computer to another.
Pen drives are small, convenient, and have large capacities (1GB to 2TB).

Cloud storage is an internet service that provides storage to computer users.### Cloud Storage Services
Examples of cloud storage services include Mega Limited, Filen Cloud Dienste UG, pCloud, Google Drive, Dropbox, and Microsoft OneDrive.

Main reference: O'Leary, T.J., O'Leary, D.A., & O'Leary, L.I., (2017). Computing Essentials 2017: Making IT Work for You. New York: McGraw-Hill Education.
Additional reference books include:
- Vermaat, M.E., et al., (2017). Discovering Computers, Essentials. Cengage Learning.
- O'Leary, T.J & O'Leary, L.I., (2008). Computing Essentials 2008.
- Shelly,G., & Vermaat, M., (2011). Discovering Computers 2011. Cengage Learning.
- Laberta, C., (2011). Computers Are Your Future Complete. Pearson Education.
- Wilson, K., (2014). Microsoft Office 2013. In Using Microsoft Office 2013. Apress.