ACSC 155 System Analysis and Design 5. Input/Output Design Dr. Stephania Loizidou Himona

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

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

Dr. Stephania Loizidou Himona 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

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

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

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

Dr. Stephania Loizidou Himona 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

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

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

Dr. Stephania Loizidou Himona 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

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

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

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

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