Information: Policy, Strategy and Systems Module Overview A2 ICT – Module 5 Information: Policy, Strategy and Systems Module Overview

Module Overview POLICY – a plan of action adopted by an individual or group [in this instance related to ICT] STRATEGY – planning in the long term for the success of an organisation SYSTEMS – a group or combination of interrelated, interdependent, or interacting elements forming a collective entity

Structure of Module 5 Structure of Module 5 14.1 – Policy and Strategy Issues 14.2 – Software 14.3 – Database Management Concepts 14.4 – Communication and Information Systems 14.5 – Networks 14.6 – Human Computer Interaction 14.7 – Human Computer Interface 14.8 – Software Development 14.9 – Software Reliability 14.10 – Portability of Data

Policy and Strategy Issues What is the difference between a ‘policy’ and a ‘strategy’? A strategy is devised at the relevant level of management and is a long-term plan of change and improvement for an organisation. STRATEGY A policy is a document written to structure and outline the strategy to those that it affects and to those who must implement it. POLICY

An Information Strategy What strategic elements should a policy contain? STRATEGIC PLANNING ISSUES Hardware and software choices Consistency with business priorities Centralisation or decentralisation? Different user needs

Planning Issues STRATEGIC PLANNING ISSUES Consistency with business priorities STRATEGIC PLANNING ISSUES Centralisation or decentralisation? Different user needs Hardware and software choices

Centralisation or decentralisation? Centralised Information Systems Department Other Department Other Department

Backup Strategies Insurance against: Frequency Data (to be backed up) Accidental damage Equipment failure Deliberate damage Frequency Data (to be backed up) Media e.g. RAID Storage Location

Backup Procedures Full Incremental Differential Grandfather – Father - Son

Software Acquisition ‘Off the shelf’ packages purchased Customised Developed by “end user” Developed in-house External consultant Leased

Software Evaluation Criteria Functionality Compatibility Ease of use Support Technical Documentation Cost Speed Upgradability

Evaluation Report An introduction outlining purpose Methodology used to evaluate software The actual evaluation Software capabilities System requirements Results of benchmark tests Upgrade facilities Compatibility with existing software Recommendations Justification for the recommended purchase

Software Testing Alpha Beta Acceptance testing

Software Maintenance Perfective Adaptive Corrective “Laws” of software maintenance Lehman and Belady 1985 The law of continuing change The law of increasing complexity The law of large program evolution The law of organisational stability The law of conservation of familiarity

Flat File Databases - Problems Data redundancy Data inconsistency Program-data dependence Lack of flexibility Data not shareable

Relational Databases Tables (entities), records, fields (attributes) Relationships links tables (Entity relationships) Normalisation Standard notation Entity names are in CAPITALS Primary keys are underlined Attributes are shown in brackets, separated by commas MEMBER(member no,name, address)

Entity Relationships One-to-one one-to-many many-to-many one product has one barcode one-to-many one company can have many branches many-to-many many products can be sold in many supermarkets one one many many

Database Management Systems This is a layer of software inserted between the applications and the data, which attempts to solve the problems of “Unproductive maintenance” and “Lack of Security” Two features of DBMS are: Program-data independence Restricted user access

DBMS Purchasing programs Company Database Database Manage- ment System Sales programs Finance programs Payroll programs Personnel programs

DBMS - Risks One user could change data that is used by every one. How is confidential data kept safe? What if the hardware fails?

DBMS - Administration The DBA’s tasks include the following: Data storage, retrieval and update Creation and maintenance of the data dictionary Managing the facilities for sharing the database Backup and recovery Security

The Data Dictionary Contains information about the database ‘database about the database’ What tables are included and the fields in them Name and description of each data item The characteristics of data items such as length and data type Any restrictions on the value of certain fields Relationships between items of data Control information such as who is allowed to access data. Which users have read/write privileges.

Client – Server Database Database operated over a network Client sends query, server does processing, results returned to client Consistency is maintained – only one copy of database (on server) Client stations can update the server database Appropriate report can be held on client workstations Communications time between server and client is minimised only results are sent back to client An expensive resource available to a number of users

Distributed Database Several computers on a network each hold part of the data Each computer cooperates to make data available to the user May be necessary to sent requests and results over the network to users Each computer may keep separate copy of frequently used data Need to ensure that only latest data is used

Networks and Communication

Portability of Data & Standards

Human Computer Interface & Interaction