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

Secondary Storage

• 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

• 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.

Performance Enhancements

• 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

• 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

• 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

• 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

• 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

• 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

• 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

• 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).

Optical Storage

• Optical discs are widely used for storing software and movies.
• Laser beam alters the surface of a plastic or metallic disc to represent data.
• Types of optical discs include CD, DVD, and Blu-ray.

Cloud Storage

• 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.

Benefits of Cloud Storage

• No specific benefits mentioned in the text.

Disadvantages of Cloud Storage

• No specific disadvantages mentioned in the text.

References

• 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.

Other Resources

• Relate magazines, internet sites, newspapers, video, movie, CD-ROM, and other related web-sites.