Unit 1 Computer Science_3

Unit 1 Computer Science

1. Section 4: Checking For Errors

   • Validation and Error Handling
     • Errors
       • Compilation: When a program does not compile because of syntax errors
       • Run-Time: When the program crahses or gets stuck in a loop
       • Logic: When the programmer has made a mistake in the output is incorrect
   • Testing
     • Robust System: System that is unlikely to malfunction
     • Types of Testing
       • Dry-Run Testing: Test algorithm or program code without the use of a computer
       • Black Box Testing: Without looking at the program code. The code is run and the excpected results are compared with the actual results to see whether the program functions properly
       • White Box Testing: Tests are devised to check each possible path through the program code

2. Section 6: The System Life Cycle

   • Stages of Hardware and Software Development
     • Definitions
       • System: A whole composed of parts in orderly arrangement
       • System Analysis: The study of a complex process in order to improve its effiency
       • Manual System: A system that does not involve computers
       • Requirements Specification: A set of system objectives
       • Software Maintenance: updating a program to correct faults or improve features
   • System Development Life Cycle
     • 1) Analysis
       • Study of a complex process to produce a requirements specification or system objectives
         • Changes in the organisation. Technical Developments. Outdated Practices
         • Fact Gathering Methods: Interviews, Observation, Questionnaires, Examinations of documents.
     • 2) Design
       • Specification of all specification of all software, hardware, data files, test plans
     • 3) Implementation
       • Software development, installation, data preparation, training, documentation
     • 4) Testing
       • During program development andbefore the whole system goes live
     • 5) Evaluation
       • See whether the system solves the problem effectively

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