1.3 Storage Version 2

1.3 Storage Version 2

1. Secondary storage

   • Non-Volatile
   • Medium storage which stores files and programs.
     • If without, software will need to be installed each time (e.g. doesn't save data, files, images ,videos, etc)
   • Examples
     • Hard drive
     • Solid state drives
     • USB sticks
   • Long-term memory
   • To access things again later
   • To use software
   • To interact with the computer

2. Magnetic devices

   • Disks are read and written to with a moving head inside the disk drive
   • Susceptible to damage due to moving parts
   • Can be Internal or Portable
   • Cheap and high in capacity.
   • Vulnerable to magnetic fields
   • To read data, the head makes a note of whether the section is magnetised or not.
   • Examples
     • Hard disk drive
     • Tape drive
   • One level of magnetism will be 1, next will be 0
   • Read/write move across the medium and change how magnetised that part of the medium is

3. Solid state devices

   • Has no moving parts
   • Referred as Flash memory
   • Solid-State Drive, SD cards and USB memory sticks
   • Retains an electronic charge using logic gates
   • Requires little power
   • Light weight and easily accessed
   • Non-volatile
   • Durable
   • Made of micro-chips
   • No moving parts
   • Made of microchips (Switches)
   • State of the switches determine if a 1 or 0 is stored

4. Optical devices

   • Includes CD, DVD and Blu-Ray disks
   • Lasers used to read and write on a disk
   • Stored on tracks around the disk which series of pits represent binary
   • Laser makes pattern onto the disk
   • Detects where marks are and translate this into a readable pattern
   • Not very good at speed, capacity and reliability

5. Cloud storage

   • Refers to saving data in an off-site location maintained by another party
   • Examples
     • Dropbox
     • Microsoft
     • Google
   • Relies on the internet connection to upload and download the files from the server

6. Characteristics of Storage Devices

   • Capacity
     • How much data can it store?
   • Speed
     • How fast can it access data?
   • Portability
     • How easy is it to move from one place to another?
   • Durability
     • How well does it last?
   • Reliability
     • How consistently does it perform?
   • Cost
     • How much does it cost per KB, MB or GB?

7. Data Capacity (Highest to Lowest)

   • GB
     • 1 billion Bytes
   • MB
     • 1 million Bytes
   • KB
     • 1,024 Bytes
       • 1,000 Bytes
   • Byte
     • 00,000,000
   • Nibble
     • 0,000
   • Bit
     • 0