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1. Characteristics of storage devices

   • cost
   • Reliability
   • Durability
   • Portability
   • Speed
   • Capacity

2. Storage Units

   • Gigabyte (GB),1,000 MB
   • Terabyte (TB), 1,000 GB
   • Megabyte (MB), 1,000 KB
   • Kilobyte (KB), 1,000 bytes
   • Byte, 8 bits
   • Nibble, 4 bits
   • Bits (1 or 0), Smallest
   • Pettabyte (PB), 1,000 TB, this is rare but there are even larger
   • Past a byte tradititonally they go up x1,024 each time but in exams just use x1,000

3. Data Types

   • Dara = 8B
   • Real = 4/8B
   • Boolean = 1B
   • Integer = 4/8B
   • Text = 1B/character

4. Forms of storage

   • Magnetic
     • Read/write makes certain parts more/less magnetised
     • How magnetised each part is represents a 1 or 0
   • Solid state
     • The state of each chip represents a 1 or 0
     • Made of microchips
   • Optical
     • A laser light leaves markings on a desk
     • Another laser scans these and makes them into a readable format
   • Secondary
     • It lets us use software
     • We need it to interact with computers
     • Without it, you couldn't store data and so would need to redownload everything with every boot up

5. Data Capacity

   • 1 byte per charater + 10% for any overheads
   • bytesPerSample * samplesPerSecond * channels * duration = size
   • (Number of pixels * Number of bytes per pixel) + 10% for any overheads