“What do I do ?”, “How do I do it ?”, What do I do it with ? Requirements Specification, Design Specification & System Specification “What do I do ?”, “How do I do it ?”, What do I do it with ?

Learning Objectives: describe the contents of the: requirements specification, design specification, system specification, ..... distinguishing between them.

Specifications

Requirements Specification produced during analysis stage i.e. after the investigation phase by the Systems Analyst contains client requirements what the client would like the system to do setting targets for the system (deliverables) the requirement specification is a contract between client & developer success (& payment) will be determined by the contents

Requirements Specification “what the client would like the system to do” input needs data entry screens (& data validation) data to be stored entities processing requirements searches calculations output needs on-screen results required reports required

Design Specification Documentation produced by the designer showing: “How” the solution is to be implemented the data dictionary tables, fields, data formats, validation routines & error messages, relationships, ERD sketches of input screen layouts sketches of output layouts (eg reports) house style: fonts, colours, sizes & styles to use types of data entry to use (combo box, option buttons ...) button actions and other processes formulae & calculations required flow charts

System Specification identifies minimum software and hardware required in order for the system to run effectively. Includes: input devices required (keyboard, mouse, ......) output devices required (monitor, printer, .....) processing power required (type, cores & clock speed) memory (RAM) required amount of storage required (hard drive capacity) security requirements (anti-virus, firewall ...) operating system applications software