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Revision (Tom Butler (Defensive design (Why use defensive design
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Revision
Tom Butler
Authentication
login
A user may chose to have a login to ensure that their data is secure. A login usually consists of a username and a password. The username is unique and no other person/user will have the same one. The password is a personal word, phrase or combination which nobody else knows so that you are the only person who can access the data.
Defensive design
Why use defensive design
Defensive design ensures that a program is reliable and works properly.
It is used to protect valuable and sensitive data. This includes data such as bank accounts and medical records.
How do companies defensively design?
-Pay people to break the code. (Then make the appropriate changes.
-Predict how a user may make input errors.
-Get users to test the code. (Beta)
-Maintain the code to make it easy to understand.
-Try to work out how a user may try to misuse/break the program.
Reliability
A reliable program will:
-Never break.
-Never produce errors.
-Will be updated if it is outdated or if there is a problem.
The process
Analysis:arrow_right:Design:arrow_right:Implementation:arrow_right:Testing:arrow_right:Evaluation:arrow_right:(Analysis)... :repeat:
Testing
Final testing
Finally testing is when you test your program at the end once your have finished writing your program this mean that you don't have to do multiple tests throughout your program however This may also make it harder to correct the code or you may even have to start again.
Ben Handley
Errors
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Logical Errors
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It just does the wrong thing - it does what you have told it to do, but you've told it to do the wrong thing
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Verification
Methods of verification
Double entery
Entering data twice and comparing two copies. This effectively doubles the work load, and as most people are paid by the hour, it costs more two
Proofreading data
this method involves someone checking the data entered against the original document. This is also time consuming and costly