Types of Hard Disks

Secondary Storage

• Secondary storage devices are used to save, back up, and transport files from one computer to another.
• Data storage has expanded from text and numeric files to include digital music files, photographic files, video files, and much more.
• Secondary storage devices with greater capacity are required to efficiently and effectively use computers.

Characteristic of Secondary Storage

• Media: the actual physical material that holds the data and programs (e.g., hard disk).
• Capacity: measures how much data it can hold.
• Storage devices: hardware that reads data and programs from storage medium.
• Access speed: measures the amount of time required by the storage device to retrieve data and programs.

Hard Disks

• Two types of hard disks: internal and external.
• Internal hard disks:
  • Located within the system unit.
  • Able to store and retrieve large quantities of information quickly.
  • Used to store programs and data files.
  • Have a fixed amount of storage.
• External hard disks:
  • Use the same basic technology as internal hard disks.
  • Provide slower access.
  • Connected to a USB.
  • Removable.
  • Have a fixed amount of storage.

Hard Disk Organization

• Hard disks organize files using tracks, sectors, and cylinders.
• Tracks: rings of concentric circles.
• Sectors: invisible wedge-shaped sections of each track.
• Cylinders: run through each track of a stack of platters.

Solid-State Storage

• Unlike hard disks, which rotate and have read/write heads that move in and out, solid-state drives have no moving parts.
• Data and information are stored and retrieved electronically from these devices.
• Examples: solid-state drives (SSDs), flash memory cards, and USB drives (Flash drives).
• Solid-state drives: faster, more durable, and more expensive than hard disks, with less capacity, but require less power and increase battery life.

Optical Discs

• Use laser technology.
• Can hold over 128 GB of data.
• Data is represented by flat areas called lands and bumpy areas called pits on the disc surface.
• Examples: CDs, DVDs, and Blu-ray discs.
• CDs: offer 700 MB of storage, often store music.
• DVDs: store 4.7 GB, often store movies or software.
• Blu-ray discs: offer 50 GB of storage, often store high-definition video and the newest video games.

Cloud Storage

• With cloud computing, the Internet acts as a "cloud" of servers that supply applications as a service rather than a product.
• Provides cloud storage, also known as online storage.
• Examples: using Google Drive Docs to create a word processing document or a spreadsheet.
• Benefits: maintenance, hardware upgrades, and file sharing and collaboration.
• Disadvantages: access speed and file security.