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All Higher Computing (Software Design and Development (Pre-defined…

- - - - They are used as a placeholder within a subprogram for the values received or sent to the main programs actual parameters
    - - It is the actual value that is passed into the procedure
  - - - It can be accessed and altered from any part of the program, even from another script/event so long as it is declared at the very start
      - They should be used with care as their values may accidentally change if the programmer forgets that they have already used them in another subroutine
      - Their scope is the whole program because it is visible throughout the program
    - - They are created when the subroutine is called and are then destroyed when the subroutine terminates
      - They cannot be accessed or assigned a value except within that subroutine
      - They exist within one subroutine, function or procedure
      - Advantages of using them
        
        It prevents them from being used elsewhere in the program
        
        It prevents them from having their contents accidentally changed
        
        The same variable name can be used more than once in different parts of the program
        
        They aid modularity of a program
      - Their scope is limited to a single procedure or function
  - - - It is used when a parameter is needed in a subroutine but its value is not going to change in the subroutine
      - The subroutine will be passed a copy of the original parameter, so that the original parameter remains unchanged
    - - Used when a parameter is needed in a subroutine and its value is going to change in the subroutine when it is passed in
      - The subroutine will be passed the original parameter and any changes made in the subroutine will result in a change to the original value(s) held within the parameter
      - We use by reference when passing an array regardless of whether or not it is changing because if it was by value then the variable will be copied including all of the values even if there are hundreds of them
  - - - It returns a single value when called from the main program and consists of a heading, a declaration part and an action part
    - - The repetition of lines of code is avoided
      - Testing of the procedure code can take place in isolation from the main program
      - Procedure code can be saved and re-used in future projects by creating a module library
      - Debugging of the main program is simplified as each procedure can be individually tested
    - - It produces an effect when called from the main program and consists of a heading, a declaration part and an action part
  - - - A substring is when we pull some of the characters from a string
        
        Ex) string = "computing science" print(string[0:3]) the output will be com
        
        First three letters -> string[0:3]
        
        7th letter onwards -> string[6:]
        
        Last 3 letters -> string[-3:]
        
        5th letter from the end -> string[-5]
    - - integer to ascii chr()
        
        number = 65, asciiChar = chr(number), print(asciiChar) Output will be A
      - ascii to integer ord()
        
        character = "A", print(ord(character)) Output will be 65
    - - floatingPointNumber = 1.123456789, integerNumber = int(floatingPointNumber), print(integerNumber Output will be 1
    - - print(93%5) Output will be 3
- - - - Mouseover
    - - Low fidelity prototype
      - Multilevel structure
    - - Must be tested on different devices
      - Must be tested on different browsers
- - - - 2) The processor activates the read line on the control bus
      - 3) The contents of the memory location are transferred along the data bus into the data register
      - 1) The processor sets up the address bus with required memory address
    - - 2) The processor sets up the data bus with the data to be written to memory
      - 3) The processor activates the write line on the control bus
      - 1) The processor sets up the address bus with required memory address
      - 4) The contents of the data register are transferred along the data bus into the memory location
    - - 2) Activate the read line
      - 3) Instruction move along data bus and into instruction register
      - 1) Address bus set up with address
      - 4) Decode and carry out instruction
      - 5) Repeat until end of program
  - - - The width of the data bus affects how much data can be transferred between the processor and main memory at one time
      - Increasing the data bus from 64 to 128-bit doubles the amount of data that can be transferred in a single operation which improves system performance
    - - The control unit checks cache for instructions before requesting the data from RAM which saves going there repeatedly
      - The more cache there is, the more data that can be stored near the CPU
    - - Each core contains an ALU, control unit and registers
      - CPUs with multiple cores have more power to run multiple programs at the same time
      - Each core communicates with each other through channels, this uses up extra speed but it does improve system performance
    - - Clock speed (MHz or GHz) is a measure of how quickly a CPU can run. It relates with how many instruction cycles the CPU can deal with in a second
      - Max Clock Speed
        
        Overclocking is when people try to change the max clock speed to make their computer work faster
        
        They can overheat if forced to work harder than they were designed to
        
        If the clock tells the CPU to execute instructions too quickly, the processing will not be completed before the next instruction is carried out which can lead to corrupted data.
- - - - These are the processes and functions the system has to perform along with the information the system will have to store to carry out these processes and functions.
        
        Is a search facility required?
        
        Are there videos or sounds that require playing?
        
        Which pages link to other pages?
        
        Are there images that require to be displayed?
        
        What pages are required?
    - - These are what the users of the website expect to be able to do on the website.
        
        Are there any documents the users wish to download?
        
        Do the users need to access external pages?
        
        Are there images the users wish to see?
        
        Is there particular information for the users to read?
  - - - A website structure showing how the identified pages will be linked
      - Wireframe models showing how the content of pages, including forms, will be laid out
      - Low-fidelity prototypes to test the usability of the website
    - - Basic plans for how the content of each page will be laid out which involve:
        
        Where text will be positioned
        
        The position of media elements such as graphics, sound and video
        
        File formats of the media used during implementation
        
        Where navigational bars will be positioned
        
        Where the user can interact with page content
        
        How input forms will be laid out
      - They may also outline the details of any forms which may include:
        
        A drop-down menu to select one or more items from a list
        
        A button to submit the form for processing
        
        Radio button input allowing selection of one item from a list
        
        Notes showing required inputs
        
        Maximum or minimum values
        
        A larger box for entering longer pieces of text
        
        A box for entering text or numbers
    - - Created on paper to give end user idea of how it will look to get feedback and save time.
        
        Can also be created using a variety of different methods. Some may be entirely hand drawn where others may be sketched using a graphics application and printed, both include actual graphics
      - Usability Testing
        
        Where hyperlinks and interactive content are simulated. May include more targeted testing.
      - Personas
        
        Users are asked to interact with the prototypes by adopting character traits of potential users which may include:
        
        Non-targeted users who do not use the website as intended
        
        Targeted audiences who haven't visited the site before
        
        Regular users who will be familiar with the site
      - Test Cases and Scenarios
        
        Users may be given a very specific task to test for example:
        
        Find this specific piece of information on the site
        
        From this page navigate to the page about _
        
        Buy three of this product
        
        What would you do if an error is given when you try this?
- - - - Sprints
        
        Each sprint draws on the iterative development process with the principles of analysis, design, implementation and testing
        
        They are planned delivery schedules for a particular part of the system
      - Disadvantages
        
        Following a sequence of sprints and communicating this often can take up a lot of time
        
        The emphasis on team work and face-to-face communication makes longer or larger projects unrealistic
    - - Prototyping early in the process is also important
- - - - Examples
        
        Using < instead of >
        
        Using AND instead of OR
  - - - Example
        
        Dividing something by zero
  - - - Examples
        
        Forgetting to include speech marks
        
        Missing a character
- - - - Extreme data is data that is on the limit of the acceptable range. (The highest and lowest possible numbers that are still acceptable)
    - - Values that are outside the range and are unacceptable. This includes imputing text instead of a number etc.
    - - Normal data is regarded as data that should be accepted and handled correctly, it should be within the range
- - - - The general description of the software
    - - The list of things that a project must deliver to the client and/or end user. May include design, completed program, the test plan/results and the evaluation report. May also include project time limits
    - - The limits that define what is and isn't in the project, while clarifying any assumptions about the client's requirements
    - - States what functions a software must do like calculation or data input. Must be in terms of inputs, processes and outputs
  - - - Any manipulation or calculation using data that is input and will be output
    - - Data which is passed out of the program to the screen or perhaps into a file
    - - Any user input or data the program needs to process