Computer Storage Devices

Data Storage and Retrieval

• Data must be saved as a file to preserve its contents after the computer is switched off.
• Examples of storage devices:
  • Hard disk: fixed inside the computer, stores large volumes of data, and can be accessed and retrieved quickly.
  • Floppy disk drive: uses removable disks (floppies), can transfer small files between PCs (up to 1.4 MB).
  • ZIP/JAZ drives: special disks that can hold more data than floppy disks (up to 100 times more).

Optical Storage Devices

• CD-ROM drive: reads data from CDs (up to 800 MB), suitable for multimedia applications.
• DVD-ROM drive: stores up to 17 GB of data, designed for video and multimedia applications.
• CD-R, CD-RW, DVD-R, and DVD-RW drives: allow writing and rewriting data on CDs and DVDs.

Internet Access and Security

• A modem and Internet Service Provider (ISP) are required to access the Internet from home.
• Search engines (e.g., Google, Yahoo) help find information on the Internet.
• E-commerce (online business) is safe, as credit details are encrypted when transmitted over the Internet.
• Email is a quick way to send and receive messages, with attachments (e.g., files, photos).

Computer Viruses

• Types of viruses:
  • File virus: resides in memory and activates when a specific program is run.
  • Boot sector virus: infects the boot sector of a diskette or hard drive, gaining control of the system.
• Viruses can spread through:
  • Internet downloads
  • Pirated software
  • Exchange of diskettes
  • Email attachments
  • Infected documents
• Protection against viruses:
  • Anti-virus software scans files for virus signatures and updates regularly.
  • Cleaning or disinfecting infected files.

Working Environment

• Desktop: the screen background with windows, icons, and taskbar.
• Icon: a small graphical symbol representing a program, file, or function.
• Window: a rectangular area for working on an application.
• Taskbar: displays open applications, start button, and allows minimizing and closing windows.
• Cursor (mouse pointer): used to select commands or icons, controlled by mouse or keyboard.

Mouse Actions and File Management

• Mouse actions:
  • Click: quickly press and release the left button.
  • Double-click: click the left button quickly twice.
  • Drag: press and hold the left button, then move the cursor.
  • Drag and drop: drag an object to a new position, then release to drop.
• Renaming a file or folder: right-click, select Rename, type a new name, and press Enter.
• Cut, Copy, and Paste commands:
  • Cut: move information to a new location.
  • Copy: create an identical copy, keeping the original intact.
  • Paste: place the information in the new location.

Deleting Files and Folders

• Delete information only when it's unnecessary or for confidentiality purposes.
• Confirm the deletion is necessary and the information won't be needed in the future.