ACSC 155 System Analysis and Design 5. Input/Output Design

1. ACSC 155 System Analysis and Design5. Input/Output Design Dr. Stephania Loizidou Himona

2. Input/Output Design • User Interfaces Dr. Stephania Loizidou Himona

3. Data Entry Methods and Devices • Keyboard • (QWERTY) • Ergonomic • Touch-sensitive • Musical • Mouse Dr. Stephania Loizidou Himona

4. Keyless Data Entry • OCR (optical character reader) • OMR (optical mark reader) • MICR (magnetic ink character reader) • Barcode readers • Pen Input • Scanners • Graphics Tablet • Microphones Dr. Stephania Loizidou Himona

5. Output Methods and Devices • Screens • Printers • Speakers Dr. Stephania Loizidou Himona

6. Graphical User Interfaces (GUIs) • A method of user communication with an operating system. Basically, to give commands. • By selecting icons, buttons, bars or boxes. • Quick and easy to learn. • Promote standardisation of application program interfaces. • Reduce errors. Dr. Stephania Loizidou Himona

7. System User Issues for Input Design • Volume of input should be minimised • Enter only variable data, do not enter constant data • Do not input data that can be calculated or stored in computer programs • Use codes for appropriate attributes • Source documents should be easy for system users to complete • Include instructions for completing the form • Minimise the amount of handwriting Dr. Stephania Loizidou Himona

8. Design documents so that they can be easily and quickly entered into the system • Data to be entered should be sequenced • Portions of the form that are not to be input are placed in or about the lower right portion of the source document Dr. Stephania Loizidou Himona

9. System User Issues for Output Design • Computer outputs should be simple to read and interpret • The timing of computer outputs is important • The distribution of computer outputs must be sufficient to assist all relevant system users • The computer outputs must be acceptable to the system users who will receive them Dr. Stephania Loizidou Himona

10. Internal Controls for Inputs and Outputs • The number of inputs should be monitored • Care must also be taken to ensure that the data is valid • The timing and volume of each output must be precisely specified • The distribution of all outputs must be specified • Access controls are used to control accessibility of video (on-line) outputs • Control totals should be incorporated into all reports Dr. Stephania Loizidou Himona

11. ISAM – Indexed sequential access method • For storing data records on a physical storage device in sequential order for sequential processing • Allows direct access to the particular record • Batch mode versus On-line processing • Methods of interacting with a system - command language - menu - form - object - natural language Dr. Stephania Loizidou Himona

12. Fourth-generation language • Extremely sophisticated languages • Little or no professional programming skills • Categories (7): • Query languages • Report generators • Graphics languages • Application generators • Very high-level programming languages • Application software packages • Microcomputer tools Dr. Stephania Loizidou Himona

13. Testing and Debugging • Testing • Black box testing • White box testing • Alpha and Beta testing • Selection of test data Dr. Stephania Loizidou Himona

14. Debugging (Errors or bugs) • Translator diagnostics • Cross-referencing, Traces, Variable dumps • Dry runs • Splitting the program • Test strategies Dr. Stephania Loizidou Himona

15. Installation - Integration • Parallel running • Pilot running • Big bang, or direct change • Phasing Dr. Stephania Loizidou Himona