Section 02Systems Documentation1 02 Systems Documentation And Franchise Colleges By MANSHA NAWAZ

Section 02Systems Documentation2 Learning Aims –to understand the documentation requirements for computing projects –systems development activities –to be able to draw up a Terms of Reference for a proposed small scale computerised system

Section 02Systems Documentation3 DOCUMENTATION OVERVIEW

Section 02Systems Documentation4 Developing Computer Systems TEAM – share system development tasks –Size of development team –Size and scope of project –Skill & experience of the team …. Documentation used to communicate.

Section 02Systems Documentation5 Early Systems Development First systems no method or special techniques –used flow charts –used english text experience & rule of thumb Growth period systems became –larger –more complex –more numerous problems arose –late –over budget –bugs

Section 02Systems Documentation6 The Solution Needed was a way to –handle lots of detail –produce reports specific to stage of development –allow communication analyst - customer Structured Methodologies –Yourdon, DeMarco, Gane & Sarson –later SSADM, Waterfall, etc

Section 02Systems Documentation7 Structured Methods ordered set of related techniques specific to needs of the various stages mainly graphical models but supported with text manageable training & guidance available

Section 02Systems Documentation8 STRUCTURED METHODOLOGIES –used to document all systems to a universally accepted defined standards Documentation standards – use the same tools Speak the same language - use the same tools Structured Methodology tool of interest : –Computer Aided Software Engineering Tools & Techniques (CASE) Please Note There are many different CASE Tools and Techniques available

Section 02Systems Documentation9 The Techniques See Supplement 02 Computer Aided Software Engineering Tools and Techniques (CASE) Computer Aided Software Engineering Tools and Techniques (CASE)

Section 02Systems Documentation10 CASE Tools and Techniques of interest Data Flow Diagrams –context diagram, top-level dfd, explosions Data Dictionaries –data description, process logic Normalisation –Design technique for database tables Entity Relationship Diagrams Database Development –Modelling technique for database tables

Section 02Systems Documentation11 Graphical models short precise compared to english narrative abstract, focus on essential detail hierarchical, levels of detail partitionable, view different parts minimally redundant, easy to change transparent, see ‘reality’ not technology

Section 02Systems Documentation12 Computers and Reality The real world consists of people, places, forms, letters, documents Non of these exist within the computer Our models reflect this by showing a LOGICAL view of the system The models (dfds) show what happens to data about things in the system & not what happens to the actual things

Section 02Systems Documentation13 For the purposes of this module we are going to restrict our SYSTEMS METHODOLOGY to utilise the following : CASE Tools and Techniques of interest Data Flow Diagrams – context diagram & Events List – top-level dfd – low-level dfd’s (explosions) Data Dictionaries –Data Description –Process Descriptions Normalisation

Section 02Systems Documentation14 For the purposes of this module we are going to restrict our SYSTEMS METHODOLOGY to utilise the following : Systems Documentation Analysis Specification Design Specification

Section 02Systems Documentation15 Document : Analysis Specification –Terms Of Reference lecture 02 lecture 02 Statement of Purpose Requirements Functions Constraints –Context Diagram & Events List lecture 03 lecture 03 –Top-Level Data Flow Diagram lecture 04lecture 05 lecture 04lecture 05 –Low-Level Data Flow Diagrams lecture 06lecture 07 lecture 06lecture 07

Section 02Systems Documentation16 –Data Dictionary lecture 08 lecture 08 Data Stores - Structures & Elements lecture 08 lecture 08 Data Flow - Structures & Elements lecture 08 lecture 08 Data Stores and Flow Usage lecture 09 lecture 09 Process Descriptions lecture 10 lecture 10 –NORMALISATION lecture 11 lecture 11 Database Tables derived from Data Store Descriptions Document : Design Specification

Section 02Systems Documentation17 DOCUMENTATION IN DETAIL

Section 02Systems Documentation18 For the purposes of this module we are going to restrict our Terms of Reference to the following sections: Terms Of Reference Statement of Purpose Requirements Functions Constraints

Section 02Systems Documentation19 Is an introduction to the project environment Short English narrative highlighting the customer background and current situation Description of the area to be investigated –what is inside the system boundary Business activities System environment - physical area Organisation & structure Systematically refined and added to as we gain more awareness of the system environment TERMS OF REFERENCE

Section 02Systems Documentation20 Short English narrative highlighting what the proposed system should do Systematically refined and added to as we gain more awareness of the system STATEMENT OF PURPOSES

Section 02Systems Documentation21 To achieve its purpose the proposed system will have to perform a variety of operations –record sequentially in a numbered list –each a statement of a required function –include general must do things –no detail of how to do –no detail of the overall structure Systematically refined and added to as we gain more awareness of the system Functional Requirements

Section 02Systems Documentation22 CONSTRAINTS Customers often place other constraints that have nothing to do with the system function. –Non-functional Requirements –delivery time –run on specified hardware platform –use of specific language/software –record sequentially in a numbered list

Section 02Systems Documentation23 Summary Stages involved in Systems Analysis Stages involved in Systems Design What CASE tools we will use What documentation we will produce Establish Terms of Reference –Terms Of Reference Statement of Purpose Requirements Functions Constraints

Section 02Systems Documentation24 Self Study Review the lecture Complete task 2a & b in the workbook can you achieve the aims stated in slides 2? Check Further Reading Section following the next slide

Section 02Systems Documentation25 Further Reading Supplement 02 Systems Theory online only Systems Theory available online

Section 02Systems Documentation26 Further Reading Supplement 02 Establishing User Requirement online only Establishing User Requirement available online

Section 02Systems Documentation27 Further Reading Supplement 02 Rich Picture.doc Rich Picture.doc available online

Section 02Systems Documentation28 References Hoffer, J.A. et.al. “Modern Systems Analysis & Design” 3rd Ed. Addison-Wesley 2002 Ch1, pp11-15, Ch2-3 Ch4 pp Bennett, S. et. al. “Object-Oriented Systems Analysis & Design using UML” McGraw-Hill 1999 cCh1 pp18-20, Ch3 pp55-60, Ch11 pp245-7 Parkin, A. (1987) “Systems Analysis” Edward-Arnold Reading: –Bennett et al, Chapter 5 –Hoffer et al, Chapter 7 pp 202–237 Reference source: –David Budgen, Software Design, Addison Wesley, 1993