MP3 format needs to be decoded when used,
which means they do not load as quickly as some
other formats.
Sound signals need to be converted
before they can be processed by a
computer because sound signals are
analogue, computers are only able to
process digital signals.
A Interface that allows a musical
instrument and a computer to
communicate with each other is
called Musical Instrument Digital
Interface (MIDI)
Input/Output Devices
An input is data that a computer receives.
An output is data that a computer sends.
Computers only work with digital information. Any input that a computer receives must be digitised.
Analogue & Digital
Often data has to be converted back to an analogue format when it's output, for example the sound
from a computer's speakers.
Computers only work with digital information. Any input that a computer receives must be digitised.
Bitmap/Vectors
Networks
Wide Area Network (WAN)
Local Area Network (LAN)
A computer network is a number of computers linked together to allow them to share resources.
Networked computers can share hardware, software and data.
Bridge: Connects two similar networks e.g. two LANs
Gateway: Connects two dissimilar networks e.g. connects a LAN to a Wan
Switch: Analyses each packet of data and sends it to the computer it was intended for
Animation
Tweening: Process used by animation software to automatically create the in-between frames
between the two key-frames of the animation sequence
Key Frames: Key frames are the starting
and ending images of an animation
sequence.
Onion Skinning: Onion-skinning, is an option that you can turn on that shows a range of frames from
your current frame
FPS: A frame (state) is a single image within the complete animation sequence.
Persistence of Vision: The process by which the eye is fooled into thinking that still related
pictures, which are shown rapidly after each other, is actually a motion picture
ADV: Brings a topic to life It gains the attention of the
viewer Keep a young audience’s attention for longer
Extend the boundaries of the physical world
DIS: Takes a lot of effort to create even a basic animation Need skill to use animation software If
overused, can be distracting from key message Unrealistic
Verification
Visual Check – User carefully reads what has been typed in and compares with original data source
Parity Check – Ensures data sent is the same as the data received when data is transmitted from one
computer to another
Double Keying – Checks the same data enter twice matches
Validation
Validation checks that data is sensible/reasonable/within stated ranges.
Batch Totals check meaningful data. Adds up data which is meaningful E.g. The sum of the total
prices of objects in a database
Hash Total checks meaningless data/ adds up a total that does not make sense. E.g. The sum of
peoples phone numbers
Security
Non-Physical Ways Access levels/Encryption/Backups/Passwords /Usernames/Monitoring the
network/Anti-virus
Physical Ways Alarms/security locks/bars on windows/Fireproof doors/Fireproof boxes
Legal Issues
Computer Misuse Illegal to: Gain Unauthorised access to files stored on a computer system. Gain
unauthorised access to files and use them for criminal activities Change or delete files unless
authorised to do so.
Electronic Communications Act (2000)
Data Protection Act This act deals with personal data. If holding personal data you must: Store &
Process data only for lawful stated purpose. Collect and process data fairly and lawfully. Keep
adequate and relevant data. Meet the rights of the data subjects. Keep accurate & Up to date. Keep no
longer than necessary. Keep data secure. Do not send outside of the EU
Human – Computer Interface (HCI)
Biometrics:
ADV: Each individual has a unique biometric characteristic e.g. Finger print It is difficult to forge
biometric properties They cannot be shared Reduce password administration costs Replace hard to
remember passwords
DIS: Very expensive If biometric finger print is stolen it cannot be changes For people affected with
diabetes, the eyes get affected resulting in differences.
Command Line:
ADV: Quicker to type a command Little memory needed Little processing power needed No need for
expensive hardware Much less RAM needed A low resolution, cheaper monitor.
DIS: It can be confusing if someone is new There are a large
number of commands that need to be learned You can’t just
guess the instruction Not suitable for a novice
Menu Driven:
ADV: No need to learn lots of commands Ideal for beginners Little processing power needed
Extremely easy to use Step-by-step options Menu interfaces done’ have to be visual, they can be
spoken.
DIS: Poorly designed, maybe slow Can be too many menu screens to work through Cause frustration
if menus are not organised Can be tedious for experts
GUI (Graphical User Interface)
ADV: Easy to navigate Uses windows/icons/menus/pointers Easy for novices Help guides and
shortcuts for experts You do not use complicated commands Exchange data between different
software applications
DIS: Lots of memory Lots of processing power Slow for experts that just want to get things done
More RAM needed
Control Systems
Good for doing certain jobs quicker and don't need as many breaks as humans. e.g robots
However cost a lot to repair and assembly line jobs can be lost