Computer science

Computer science

1. SLR 06

   • Testing
     • Data inputs
       • Valid
         • Data that should work
       • Valid extreme
         • Unusual/Unexpected data
       • Invalid
         • Data that should cause an error
       • Invalid extreme
         • Data that is nearly acceptable
       • Erroneous
         • The wrong data type
     • Testing strategies
       • Black box
         • Comparing outputs to expected outputs when given a specific input. Disregards code itself. 
       • White box
         • The code itself is watched in order to ensure each expected step works 
       • Alpha
         • the code is tested in house
       • Beta
         • The program is tested by a small external group (closed) or is released to the public for mass testing (open)
   • Development
     • Waterfall
       • -Linear -Stakeholders are not involved in all stages of the object -Customers are only addressed at the start and end -If something is wrong, earlier steps can be repeated -Still popular but phasing out 
     • Spiral
       • -Linear  -Same idea as waterfall, but iteratively produces prototypes and takes risks into account  -Each stage is repeated multiple times with each prototype 
     • Agile
       • -A very popular model in development  -Doesn't follow a linear pattern  -Analysis, design and implementation are happening all at once (small parts at a time)  -Customer involved in all steps  -Requirements quickly change dependent on user  -Model must be kept simple  -Rapid feedback from user  -Incremental changes are made as the product develops 
     • Extreme Programming (XP)
       • -Basically agile  -instead of developing prototypes, there are frequent releases (several updates over short period of time)  -Improves productivity and introduce checkpoints at which new customer requirements can be adopted 
     • RAD
       • Repetition of developing several prototypes of lower functionality, then test with the user. 

2. SLR 05

   • Translators
     • Assembler
       • Translate Assembly language into machine code, relies on Instruction set (device reliant) 
     • Compiler
       • Program is translated entirely into assembly language before it's run. 
     • Translator
       • (Interpreters) Translates each line into lines of Assembly language whilst the code is running. 
   • Nature of applications
   • Compilers

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