TOPIC 5- Storage devices

ICT systems need to store programs and data and this storage can either in:

• Primary storage- chips inside the computer
• Secondary- outside the computer

There are two types of primary storage:

• ROM- Read only memory
  • Fast permanent memory used for holding instructions needed to start the computer
  • Non-volatile- memory stored on a chip which does not lose data when the power is switched off
  • Cannot be altered

• RAM- Random access memory
  • Fast temporary memory
  • Volatile memory
  • Can be altered

More memory

= applications run faster 

= run more applications at the same time

= able to move more quickly between applications

Secondary storage is important because it allows users to:

• Ensure that data is stored safely and securely so that it can be accessible at a later date
• Transfer data from one computer to another

Types of secondary storage:

• Magnetic disk drives
• Optical drives
• Magntic tape
• Flash memory
• Memory cards

Magnetic disk drives

Floppy disk

• Slow data transfer speed
• Very low storage capacity
• Too small and expensive for modern computing

Hard drive

• Main storage device for all computers
• High data transfer speed
• High storage capacity

Magnetic tape

• High storage capacity
• Used for backup of data and programs
• Large acess time- not used for storage needed quickly

CD -ROM

• Bought with content already on it- used for distribution of software
• Read only memory
• High storage capacity
• Very fast- data read by laser

DVD-ROM

• Holds more than a CD
• Bought with content already on it- used to store videos or sounds
• Read only memory

CD-R/ DVD-R

• Write once, read many times
• Stores data and programs permanently
• Very cheap- more efficient

Flash memory 

Advantages:

• Small, lightweight, portable
• Universal
• Large storage capacity

Disadvantages:

• Easily lost
• Left in computer
• Low data transfer speed

Data can be stored at different physical locations:

• Blog
• Website
• Emais