Chapter 15 (HL only): IT Systems in Organizations

Types of Development

• Off-the-shelf Software:

  • Definition: Software widely available and can be bought by anybody.

• Custom / Bespoke Software:

  • Definition: Software created specifically for an individual or organization.

Development Tools

• IDE (Integrated Development Environment):

  • Definition: A set of programs used by system developers to create IT systems.

  • Some of the tools in an IDE include: a text editor used to enter the program’s source code, a compiler that translates the source code into machine code, and debugging tools to help find and fix errors.

Legacy Systems

• Legacy System:

  • Definition: An old, out-of-date IT system still used because it is essential to an organization.

Emulation and virtual machines

• Virtual Machine:

  • Definition: A software implementation of a computer system, allowing one physical computer to run several “virtual computers,” each with its own independent operating system and application software.

• Emulator:

  • Definition: A computer program that simulates another type of computer, allowing it to run programs designed for it.

System development lifecycle

• SDLC (System Development Life Cycle):

  • Definition: The stages in the lifetime of an IT system, from proposal to design, creation, and eventual phasing out.

• SDLC steps:

  • Analysis: an investigation of the current system, the needs of the client, and the possibility of creating a solution.

  • Design: planning a solution to meet the client's needs.

  • Development: the creation of a system.

  • Testing: ensuring that the system functions correctly.

  • Installation: installing the software and any necessary hardware at the client’s organization.

  • Maintenance: updates and changes made to a system to fix bugs, improve performance, or add new features.

Analysis Stage

• The analysis stage involves investigating the current system, determining the organization’s requirements for a new system, and investigating and choosing a possible solution.

• Client:

  • Role: Person or organization commissioning an IT project.

  • The analysis must involve all key stakeholders, including the client and the end users.

• End-User:

  • Definition: A person who will use the IT project once it is finished.

• Project Goals:

  • Definition: Clear statement of the intentions of a proposed IT project.

  • Must be carefully defined during this phase, including its scope.

• Scope:

  • Definition: Clear definition of the boundaries of an IT project.

  • This is critical, a project with poorly defined goals is less likely to be successful.

• There are a few steps in the analysis stage, with each having several components:

1. Data Collection

• Data collection:

  • Purpose: Gather information about an existing system during the development of a new one.

  • To gather information from users, questionnaires, orinterviews can be used.

  • To gather information from the organization, developers can use organizational policies, user manuals, and technical documentation.

• Organizational IT Policies:

  • Definition: Governing policies on IT use, data integrity, and security within an organization.

• Technical Documentation:

  • Purpose: Intended for programmers and developers of an IT system.

• User Documentation:

  • Purpose: Intended for users, explaining how to understand and use the IT system.

2. Requirements specification

• Requirements Specification:

  • Definition: A clear list of functional and non-functional requirements for a proposed IT project.

• Functional Requirements:

  • Definition: Specific features and functions that a proposed IT system must have.

• Non-functional Requirements:

  • Definition: Conditions that a proposed IT system must meet, such as hardware compatibility and timing constraints.

• Constraints:

  • Definition: Limitations within which an IT system must operate.

  • This is a non-functional requirement.

3. Identification of possible IT solutions

• Projects may have several possible solutions.

4. Feasibility Study and justification of solution:

• Purpose: Examine if the proposed system is possible.

  • A solution must be chosen and justified.

• Business Case:

  • Definition: Analysis of the benefits and problems of a proposed IT project.

• SWOT Analysis:

  • Method: Used during business case creation.

  • Examines the Strengths, Weaknesses, Opportunities, and Threats.

5. Project Plan

• Project Plan:

  • Definition: Clear definition of the goals, scope, and schedule of a proposed IT project.

  • A project manager and methodology must be chosen, and milestones must be set.

  • Sometimes it is useful to use a Gantt Chart to plan ahead.

• Project Manager:

  • Role: Individual with overall responsibility for an IT project.

• Project Management Methodology:

  • Definition: Systems and techniques designed for successful projects and avoiding failure.

• Milestones:

  • Definition: Key points during project development, e.g., completion of a stage.

• Gantt Chart:

  • Purpose: Chart stages of a planned IT project and the responsible individuals.

• Project Management Software:

  • Purpose: Aids in planning, managing, and guiding IT project development.

• PERT Chart:

  • Purpose: Visualizes interdependencies in projects.

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• CP (Critical Path):

  • Definition: Longest path through a project's development, determined by PERT chart.

Design Stage

• During this stage, software developers plan a solution that fulfills the functional requirements identified during the analysis stage.

  • This stage covers the inputs, processes, data structures, and outputs required by the system.

• Outputs:

  • Purpose: A list of results that a system must produce during analysis.

• Data Structure:

  • Definition: The organization and relationship of data within an IT system.

• Processes:

  • Purpose: A list of procedures a system must implement during analysis.

Data Flow Diagrams

• Data Flow Diagram (DFD):

  • Purpose: Shows processes in a system and the flows of data between them.

• System Context Diagram:

  • Definition: High-level DFD of a system.

• DFD Symbols

  • Process: represented by a circle with the name of the process inside. There must be at least one arrow for input and for output.

  • Sink: represented by a rectangle with the name of the process inside. This is a data source or destination outside the system's scope, it’s a process performed by somebody else.

  • Data store: two lines, with the name of the data being stored inside.

  • Data flow: an arrow, with the name of the data indicated. It shows the direction of flow.

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Entity Relationship Diagrams

• Entity Relationship Diagram (ERD):

  • Purpose: Shows items of data stored in a system and their relationships.

  • It shows the groups of data stored (entities), the attributes each entity has, and the relationships between various data items.

  • It also shows the cardinality between the various data items.

• Entity:

  • Represent database tables.

  • Shown as a list inside a rectangle, listing the attributes belonging to that entity.

  • The primary key is clearly indicated.

• Attributes:

  • Fields of information that each entity has.

  • There is a primary key per entity, which is a unique ID that identifies each row of the table.

• Relationships:

  • Definition: Links between separate items of data.

  • Shown as a line, with its names (one for each direction)

• Cardinality of relationships:

  • The quantity of attributes that another attribute can relate to.

  • Cardinality symbols should be shown on each side of the line.

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• User Interface:

  • Definition: The part of a system that allows a user to interact with it.

  • Designed at this stage, with prototypes done to show the client.

• Prototype Interface:

  • Purpose: Early version of a user interface to gather feedback about its effectiveness.

Implementation Stage

• Implementation Stage:

  • Definition: Phase in the SDLC where the system is programmed.

  • Also called development or construction.

  • A team of programmers will work on creating the software using IDEs.

  • Prototypes will be made, which need to undergo testing and quality control.

• Alpha Testing:

  • Purpose: Initial testing of an IT system.

  • The program is likely to contain bugs, so testing is required to find them.

• Bugs:

  • Definition: Errors in a computer program or system, ideally found during testing.

• Software Testers:

  • Definition: Individuals who perform alpha, beta, and acceptance testing.

• Prototypes:

  • Purpose: Early versions of a project designed to get feedback from clients and users.

• Quality Control Processes:

  • Purpose: Processes to ensure code produced by programmers adheres to accepted best practices.

• Test Plan:

  • Purpose: A list of all tests and test data that should be tried with a system.

• Quality Assurance Methods:

  • Purpose: Ensures the entire development team follows standardized best practices.

• Capability Maturity Model Integration (CMMI):

  • Definition: A quality assurance method that describes an organization's level of maturity.

• Documentation:

  • Documentation is produced at this stage so that other people can work their way around the system

  • Programmers usually write comments in the source code.

  • Technical documentation is targeted at system administrators and other developers who may change the system in the future.

  • User documentation explains how to use, install, and start the system. These can be FAQs, tutorials, or online lessons.

• Frequently Asked Questions:

  • Definition: A list of common problems users may encounter, along with their solutions.

• Online Lessons:

  • Definition: Form of training delivered online.

• Tutorial:

  • Definition: A document explaining how to perform key tasks step by step.

• User Manual:

  • Definition: A document explaining to users how to use a computer system.

Development Personnel

• Project Managers:

  • Role: Oversee all IT purchases, deployments, and systems within an organization.

• Analyst:

  • Role: Documents the current system, identifies problems, and suggests areas for improvement in project development.

• Database Administrator:

  • Role: Sets up, maintains, and monitors the organization's databases.

• Development Manager:

  • Role: Oversees programmers in creating the system specified in the design during project development.

• Network Manager:

  • Role: Installs, configures, and monitors an organization's network.

• Programmer:

  • Role: Writes computer programs based on a design document.

• Support Staff:

  • Role: Trains users and assists with problems as they occur.

Testing Stage

• Beta Testing:

  • Purpose: Testing of an IT system once all features have been added, focusing on bug identification.

  • This can be done only after alpha testing has been finished.

• Beta Tester:

  • Definition: A person who attempts to find bugs in software before its release to customers.

• Bug Tracking System:

  • Purpose: Used to track and manage bugs in a piece of software.

• User Acceptance Testing:

  • Purpose: Tests performed by a client before formally accepting an IT system from developers.

• Load Testing:

  • Purpose: Testing the system's capability under real-world processing conditions.

• Acceptance Testing:

  • Purpose: Testing performed by the client and users as part of the handover process.

Installation Stage

• Installation:

  • Definition: Installing a new IT system at the client's premises.

  • Also called delivery or deployment.

• User training:

  • Purpose: Ensuring users can work with the new IT system.

  • Must be carried out before a new system can be used under real-world conditions.

• Handover:

  • Definition: The point at which developers formally pass the system to the client.

• Changeover:

  • Definition: The process of moving from an old system to a new IT system.

  • Can be done only when training is complete.

  • There are three types of changeover: direct, parallel, and phased.

• Direct Changeover:

  • Definition: Immediate removal of an old system, completely replacing it with a new IT system.

• Parallel Changeover:

  • Definition: Running the old and new systems side by side.

  • Also called parallel running.

• Phased Changeover:

  • Definition: One part of an organization switches to a new IT system for testing, while others continue using the old system.

• Delivery:

  • Purpose: Installing a new IT system at the client's premises.

• Deployment:

  • Definition: Stage in the SDLC where the system is deployed at the client's site.

Maintenance Stage

• Maintenance:

  • Definition: Alterations made to a system after it has been formally handed over.

  • When changes are made, all stages of the SDLC are applied.

  • There are four types of maintenance: adaptive, perfective, corrective, and preventative.

  • Maintenance also includes giving support to the company to fix future problems.

• Adaptive Maintenance:

  • Purpose: Changes to software to make it work with a new software environment.

• Perfective Maintenance:

  • Purpose: Changes software to incorporate new user requirements or changed requirements.

• Corrective Maintenance:

  • Purpose: Fixes bugs in software.

• Preventative Maintenance:

  • Purpose: Changes software to avoid possible future problems.

• Regression Testing:

  • Purpose: Testing to ensure changes to an IT system did not break any previously working functionality.

• Support:

  • Definition: Staff who help users with problems encountered while using an IT system.

• Internal Support:

  • Definition: Support for an IT system provided within an organization.

• Incident Tracking System:

  • Purpose: Used to keep track of problems and difficulties encountered in an IT system.

  • Also called Incident Management System.

• Incident Escalation:

  • Definition: Moving a problem with an IT project to a higher level if it cannot be solved.

• Phase Out:

  • Definition: Gradually removing an old IT system from use.

  • This is done when an IT system reaches the end of its life.

Development Approach

• The way in which the SDLC stages are approached depends on the development model used.

  • There are two approaches:

• Waterfall Development:

  • Definition: Development method that focuses on completing each stage of the SDLC for the entire project before moving on to the next.

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• Agile Development:

  • Definition: Development method focusing on creating small, working parts of a project at regular intervals.

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Project Management Methodologies

• Project Management Methodologies:

  • Aim to describe the best approaches for managing the SDLC steps.

SSADM (Structured Systems Analysis and Design Method):

• Stage 0: Feasibility study. Examines whether an IT project is feasible and why.

  • Stage 1: Investigation of the current environment.

  • Stage 2: Business system options. Presentation of different options for solving the business problem.

  • Stage 3: Requirements specification. Detailed list of requirements.

  • Stage 4: Technical system options. Involves considering hardware, software, networks, and personnel required.

  • Stage 5: Logical design. Modelling and documenting all of the required data.

  • Stage 6: Physical design. Translating previous design work into actual hardware and software specifications.

• Procurement:

  • Definition: The act of acquiring necessary items (software, hardware, staff) to develop an IT system.

PMBoK (Project Management Body of Knowledge):

• The SDLC is divided into five stages (process groups).

  • The result of these groups is fed into the next group, producing a project charter.

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PRINCE2 (PRojects IN Controlled Environments) 2:

• The SDLC is broken into stages: Starting Up, Initiating, Delivering, and Final Delivery.

  • Each stage is broken into levels: Directing, Managing, and Delivering, which describe the type of work performed.

• Project Initiation Document:

  • Purpose: Document used in PRINCE2 to describe the key features of an IT project.

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