Zusammenfassung der Ressource
Unit 1.3 Storage
- Characteristics of
storage devices
- Capacity
- Speed
- Portability
- Durabilty
- Cost
- Reliabilty
- Data Capacity
- Sound
- bytesPerSample * samplesPerSecond *
channels * duration = size
- Images
- (Number of pixels * Number of bytes per
pixel) + 10% for any overheads
- Text
Files
- 1 byte per character +
10% for any
overheads
- Storage Units
- Past a byte tradititonally
they go up x1,024 each time
but in exams just use x1,000
- Bits (1 or 0),
Smallest
- Nibble, 4 bits
- Byte, 8 bits
- Kilobyte (KB), 1,000 bytes
- Megabyte (MB), 1,000 KB
- Gigabyte (GB),
1,000 MB
- Terabyte (TB),
1,000 GB
- Pettabyte (PB), 1,000 TB, this is
rare but there are even larger!
- Data Types
- Text =
1B/charcater
- Integer
= 4/8B
- Real = 4/8B
- Boolean
= 1B
- Date = 8B
- Forms of Storage
- Magnetic
- Read/write makes certain
parts more/less magnetised
- How magnetised each part
is represents a 1 or 0
- Optical
- A laser light leaves
markings on a disk
- Another laser scans
these and makes them
into a readable format
- Solid State
- Made of microchips
- The state of each chip represents a 1 or 0
- Secondary
- We need this
storage to save data
ready for future use
- We need it to
interact with
computers
- It lets us
use
software
- Without it, you couldn't store
data and so would need to
redownload everything with
every boot up
- It's needed for more Capacity.
- It's also used for Backing-Up data.