ICT Functional Skills

ROM

Read Only Memory

• Permanent
• Long term memory
• Cannot be erased or changed in any way
• Also known as 'Non-Volatile Memory'
• Doesnt disappear after the computer is switched off
• Instruct the computer how to load the operating system from the hard drive into the computer's memory

RAM

Random Access Memory

• Temporary, short-term working memory
• Only works when computer is turned on
• 'Volatile Memory'
• Each time you start a program e.g Word it is loaded into RAM
• Amount of RAM influences processing power, speed and amount of programmes you can run at once

A single byte is made up of a series of 1's and 0's, which are known individually as binary digits or “bits”. 

8 bits = 1 byte

1024 bytes = 1 kilobyte

1024 kilobytes = 1 megabyte

1024 megabytes = 1 gigabyte

CD's:

• CD-R's are cheap
• Can be used by all modern computers
• CD-RW's can be written on more than once

• Some cannot be written to after manufacture
• Small storage capacity compared to DVD, Blu-ray, flash memory
• Easily damaged

DVD's

• Write once are cheap to buy
• all modern computers can use them
• Large storage capacity

• Rewritable DVD's are expensive
• Double-layer DVD's are expensive
• Some devices cannot use both the plus and minus type of DVD
• Cannot be used on the CD drives of older computers
• Easily damaged

Blu-Ray

• Very large storage capacity

• Devices and media are expensive but prices will fall as more people buy them
• Not usable by DVD or CD drives so a new optical drive is needed
• Easily damaged

Floppy Disk

• Easily transported
• All older computers can use them
• Not as easily damaged as hard disks

• Not commonly used in modern computers
• Very small storage capacity
• Easily lost or stolen
• Can be damaged by magnetic fields, or mishandling

Hard Disk

• Very large storage capacity
• Relatively cheap for large storage capacities compared to removable devices/media
• Easily damaged by knocks, heat, magnetic fields