• Compact Disc abbrieviated CD is a famous storage device used since 1982
  • It peaked as the most used portable storage device until 2000
  • It is usually 120 mm in diameter and holds 700 MB of space
  • It expanded into different types of discs like CD-ROM, CD-R, CD-RW, VCD, CD-i etc.
  • Data is literally burnt onto the CD using a laser hence it is called burning a CD when writing data onto a CD
  • The data is read by the laser being reflected off the burnt space going into a sensor


  1. Can hold lots of media
  2. Easy to carry
  3. Cheap


  1. Easily damaged
  2. Many types of CD are easily copied causing lot of copytright issues


  • A pre-burnt CD that can be written only once and then used for Reading only
  • Most popular in distributing computer software, video games etc
  • Can only be read on a computer and on a CD player but with audio only
  • Can hold up to 900 MB


  • It is easily transportable and is compatible with any other PC or laptop
  • Can store more data than a usual CD


  • Expensive
  • Easily damaged
  • Information is fixed therefore hard to update


  • A CD that is recordable but only once, similar to CD-ROM but it is recordable by the user
  • It is an example of Write Once, Read Many (WORM) storage
  • Mostly used as a one session backup as it is WORM type storage


  • Cheap
  • Hugely accessible for everyday use


  • With WORM storage the data burnt onto it cannot be changed once written with no way of updating the data.
  • Short lifespan


  • This type of CD is re-writable
  • It's structure is different from other CD's making it re-writable
  • It is mostly used for backing up files or when transporting files across PC's


  • Re-writable disc allows the user to update or correct the data recorded on the disc
  • Highly accessible and cheap


  • Short lifespan
  • Slower to write
  • Not compatible with older CD players and drives (11-12 years old or more)