1. Backing Storage

2. Backing storage devices allow us to store programs and data so that we can use them later Backing storage devices can be split into 4 categories: Magnetic (Hard Disk Drive) Optical (CD, DVD, Blu-ray) Solid State (Solid State Drive, USB Flash Drive) Hybrid (Hard Disk + Solid State Drive) Backing Storage Devices

3. Solid disk (made of metal or very hard plastic) Usually permanently fixed inside the computer (or close by it in its own box) Large capacity Data is stored magnetically Hard Disk

4. Data is stored on surface of the CD or DVD in a series of pits Pits are read by shining laser light onto the surface of the disk. CDs and DVDs rotate at a very high speed and the laser beam is reflected off the disks surface. Optical Storage (CDs and DVDs)

5. CD-ROM Data cannot be written to CD ROM once it has been produced Data is usually written on a CD-ROM in a factory (where it is being made/produced)

6. Data is written onto the disk using a special disk drive unit. The unit burns a permanent pattern into the surface of the disk using a high precision laser beam. CD-R disks can only be written to until the disk is full CD-R (Recordable)

7. Data is written and rewritten onto the disk using a special disk drive unit. The unit uses a high powered laser beam with 3 states High – used to record data Medium – used to erase data Low – used to read the data CD-RW (CD-Rewritable) disks can be written and rewritten many times CD-RW (Rewriteable)

8. Stores greater amounts of information than a CD A DVD can store more information because: Pits are smaller Can have two layers on each side and be double sided DVD-ROM cannot be written to once it has been produced DVD ROM

9. DVD-R and DVD+R (Recordable) Write once medium Disk can only be written to until the disk is full DVD-RW (Rewritable) Disks can be written and rewritten many times DVD-R & DVD -RW

10. Blu-ray Disk (BD) Stores an even greater amount of information than DVDs A Blu-ray can store more information because: Pits are even smaller Can have up to 4 layers on one side Disk is read by a shorter wavelength blue laser

11. BD-R and BD-RE BD-R (Recordable) Write once medium Disk can only be written to until the disk is full BD-RE (Rewritable) Disks can be written and rewritten many times

12. Solid State Drive A solid state drive stores information on memory chips There are no moving parts which means: Data can be accessed very quickly Less power is consumed More robust than hard disk More expensive and much smaller capacity than a hard disk drive

13. USB Flash Drive USB – Universal Serial Bus Device used to store data, such as pictures and movie files USB Flash Drive is a Solid State Device as there are no moving parts

14. Hybrid Drive A mixture of a hard disk drive and a solid state drive Frequently accessed data is stored on the faster to access solid state part Has large storage capacity advantage of a hard disk, and quick access advantage of a solid state drive

15. Calculating Storage How many 3Mb photos would fit on a 4Gb flash card? How many 50Mb tracks would fit on a CD?