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Computer science - Coggle Diagram

- - - - represents on or off
    - - 00110110 would equal 32+16+4+2 = 54
    - - 1 bit = a single 0 or 1
      - 1 byte = 8 bits = 1 character of text
      - (A nibble = 4 bits or half a byte)
      - 1 kB (kilobyte) = 1000 bytes
      - 1 MB (megabyte) = 1000 kB or 1000x1000 bytes
      - 1 GB (gigabyte) = 1000 MB
      - 1 TB (terabyte) = 1000 GB
      - 1 PB (petabyte) = 1000 TB
  - - - 2 characters
        
        first represents the number of sixteens (example 2 = 2*16 = 32)
        
        2nd is just the number value
        
        characters are 0-9 and A-F
        
        A-F represent 10-15
    - - 0 + 0 = 0
      - 0 + 1 = 1
      - 1 + 0 = 1
      - 1 + 1 = 0 Carry 1
      - 1 + 1 + 1 = 1 Carry 1
    - - moving places to the left to multiply or places to the right to divide
        
        it isnt always accurate whe dividing
  - - - depending what character set you use determines how many bits it has (example ascii has 7 bits but therefore can only have 127 characters)
        
        8-bit ascii is now used for things such as new symbols.
        
        on the most part though unicde is used rather than ascii
        
        a downside to unicode is that it uses much more data than ascii however its still prefered as it can be used for other languages and emoji
    - - these values can only be applied one per character so for example capital letters will have a different value than the lowercase ones.
  - - - BMP
      - JPG
      - GIF
      - PNG
      - TIFF
    - - the higher the resolution the better the image quality will be
    - - Each pixel is given a binary value
      - Each value represents a different colour
      - Using one bit per pixel allows only 2 values, 0 and 1
        
        1 = Black, 0 = White
      - the higher the amount of bits per pixel the better the colour will be as it will be more like the original
    - - Colour depth in bits per pixel
      - Resolution (Height and width in pixels)
      - Date created
      - Author
  - - - the higher the bit depth the higher the quality of the sound
  - - - removes unnecessary information to reduce file size
        
        this might be decreasing bit depth or the Hz
        
        this is commonly used for images and sound files
        
        these sound files are for general use not high quality cd's
      - it shouldn't be used for files like text files r code as valuable information will be lost
    - - lossless works by recognising patterns an storing them so less data is needed to store individual values
- - - - Should they limit free speech
        
        why should people be censored if what they say is legal
        
        should certain political views be spread
        
        being removed from a few platforms limits the person a lot as there are only a few.
      - Is it good or bad to be this connected?
    - - Smartphone apps
        
        Can monitor exersize diet or remind you to take medication.
      - Ai for medical research (eg drug development)
  - - - plastic burned releases lots of toxic fumes
      - people have to work to earn a living collecting waste and cant progress to earn more
        
        culture & ethics as well
      - 1.6million tonnes in the uk per year
      - planned obsolescence (designed unsustainability)
        
        example: apple suing and designing iPhone to be near impossible to repair
      - lithium batteries often cause fire + are dangerous
        
        the danger often leads to devices containing them not to be recycled.
  - - - general data protection regulation
      - lawful ways to obtain data
        
        consent
        
        the person agreed (example checked a box)
        
        contract
        
        processing is needed for a contract
        
        legal obligation
        
        processing data is needed to meet the law
        
        vital interests
        
        needed to protect someone's life
        
        public tasks
        
        for performing an official task
        
        legitimate interests
        
        clear benefit to the user or company (processing customer data)
      - data storage
        
        The data is kept accurate and up to date
        
        It is not kept any longer than necessary
        
        It must not be transferred to other countries unless they can keep it protected
        
        Customers must be told of a data breach within 72 hours of it happening
        
        Data must be stored so that it is protected from
        unauthorised access
    - - Using passwords for any systems with access to the data
      - Encrypting the data
      - Only allowing access to those users that need it
      - CCTV
      - Two-factor authentication
    - - Unauthorised access to computer material
      - Unauthorised access with intent to commit or facilitate a crime
      - Unauthorised modification of software or data
      - Making, supplying or obtaining anything which can be used in computer misuse offences
      - Committing any of these crimes can result in up to 10 years in prison and a fine
    - - A patent prevents anyone else using the
        invention for 20 years
      - Copyright typically lasts 70 years after publication or an author’s death
      - Copyright lets an author or musician decide how their work should be used
      - Copyrighted materials and patents are protected by the Copyright, Designs and Patents Act (1988)
      - Software Licenses
        
        propriety
        
        licensing fee
        
        commercial support
        
        no access code
        
        open source
        
        no licence fee
        
        mostly community support
        
        access and modification is possible
- - - - stores
        
        bootstrap
        
        stores the os and embedded systems
        
        BIOS
      - can only be read from (read only memory)
      - non volatile
        
        stores data when off
      - 4-8mb
    - - aka main memory, primary memory, primary storage
      - t can be read from and written to
      - stands for random access memory
      - Access to RAM is much faster than a hard drive
      - The name Random Access Memory comes from the ability of the CPU to access any part of the memory in the same amount of time
      - At any one time it will normally store:
        
        The operating system (or part currently in use)
        
        The software currently in use
        
        The data which the software is using
      - is volatile
        
        stores info when on but loses it once its turned off
      - virtual memory
        
        used when ram is full
        
        part of the hard drive
        
        considerably slower than ram
      - 4-32gb
    - - processor is fastest, then cache, then primary memory, last is virtual memory