The Software Development Process A*D*I*T*D*E*M All Day I Try to Defy Evil Milligan

Aspects of good software Good ReliablePortableHCI GoodS/W RobustMain- tainable CorrectEfficient Consistency Good error messages Unambiguous clear interface

Analysis (of ADITDEM) Client Requirements Specification +Produce Devel- opment Team Systems Specification

Analysis Techniques used Interviews;Observations Fill in Forms; and Visits; Questionaires; native wit & experience

Design (of ADITDEM)  Three consideration  HCI  data structures  Main program  Graphical design techniques  flowcharts  block diagrams  structure charts  Top down methods  Step wise refinement using pseudocode

Design (ctd.)  HCI  there are recognised rules of HCI design  Consistent visual appeal  Good error prompts  On line help  Data Structures  Arrays, lists, records, user defined – which is best for the job?  The main program  May take years  System specification will determine H/W, OS, choice of HLL

Implementation ( of ADITDEM)  The program is actually keyed in in the language chosen –Standard algorithms are used –Pre-written modules are used  A choice of language environments is made at Design stage  Various HLLs have their purposes –VB is versatile –C+ gives efficient code –Prolog is suited to knowledge based systems –Perhaps there already is an advanced package with scripting which can do the job

Implementation ( of ADITDEM) Factor affecting the HLL chosen  the type of problems the language is styled to solve  The data structures available  Control structures available (loops, branching etc)  What platform is to be used (OS & H/W) Scripting v. HLL  Both have readable sets of keywords  Both have environments with software tools  Scripting is specific to the package

Testing ( of ADITDEM)  Sets of data are created to check if the program works  Properly, test data is created at the design stage  Alpha testing is ‘in the lab’  Types of tests (conditions) –NORMAL, with normal data –BOUNDARY, with possible but extreme data –EXCEPTIONAL, trying unsusual or illegal input  Beta (acceptance) testing is ‘live’

Documentation ( of ADITDEM)  Documentation is paperwork  There are several items –At the A&D stage, requirements specification & system specification –In the hard copy program Internal Documentation –After the software is produced (you see these when you buy programs – wee booklets  User guide  Technical guide

Evaluation ( of ADITDEM)  The software engineering team have to reflect on the job done  They will have a systematic approach to gather evidence  They will measure their success against pre-decided criteria  For example feedback interviews, surveys, questionnaires, etc., trying to be objective at all times

Maintenance ( of ADITDEM)  There exists THREE types of maintenance –Corrective: to fix shortcomings or even errors –Adaptive: can we take the S/W to another setup? To another operating system? –Perfective: ‘now that we think of it, we want the S/W to do some extra bits; can it be upgraded?