SDLC: Development Phase

Software Development

Unit 2 2010

Software Development consists of:

• Acquiring the Hardware

• Acquiring the Software

• Testing the System

SDLC: Implementation Phase

Implementation Phase

• Implementation consists of converting the old system to the new system, which involves converting hardware, software and any/all associated files.

• Hardware conversion could involve replacing or upgrading a computer or a number of computers, replacing wiring/cabling, updating security measures in buildings, etc.

• Software conversion – making sure that the application (spreadsheet, database, etc.) that worked on the old system, still works on the new system.

• File conversion – (data conversion) –converting the old files to the new ones without loss. This includes the conversion of paper-based files to electronic files.

There are 4 main conversion methods:

Direct Approach(also known as Cut Over)

Users change directly and immediately from the old system to the new

Advantages• There is a fast and efficient change over• Relatively cheap methodDisadvantages• Staff can be alienated with the new system• Can lead to loss of profits and productivity

if managed badly

Parallel Conversion (also known as

Parallel Systems)

All tasks are performed by both systems until the new system is perfected

Advantages• no loss of productivity of data• staff become confident with the system because

there is time to be trained properly• problems with new system are identified and

fixed before the old system is decommissioned

Disadvantages

• expensive to run two systems

• also time consuming to run two systems

• using two systems and be confusing

Phased In Conversion

Parts of the new system are introduced gradually

Advantages• Problems with the new system can be fixed

before being fully implemented• Staff that are part of the phased conversion can

be used to train other staff• No loss of data

Disadvantages

• Can be a slow process to implement the whole new system

• Mainly used in large organisations

• At times two systems (old and new) are operated at the same time

Pilot ConversionThe entire system is tried out, but only by some users.

Once the reliability of the new system has been proved, the system is implemented with the rest of the intended users.

Advantages• Reliability is established before full implementation • Users who participate in the pilot can be used to

train the other staff

Disadvantages

• All users of a particular group are taken off the old system to participate in the pilot

Other requirements to be considered when implementing a new or modified information system:

• Physical environment may need to be modified to accommodate the new system.

• Support services will be required for the new system eg. telephone help desk

• Consumables such as stationary, printer ink cartridges, disks and disk storage facilities will need to be purchased.

• Ergonomic requirements such as glare filters for computer screens and tilt screens, higher desks, etc will need to be attended to

• The implementation of a whole new system will affect the staff who use the system.

• It may mean a change in their job roles and job specifications, which in turn may lead to the hiring of new staff with appropriate skills and retraining current staff.

• The affect on staff needs to be carefully managed as part of the implementation of the new system.

Effects on Staff

Changes to Procedures

• When implementing a new system some procedures that were used in the old system might need to be changed in the new system. Staff need to be made familiar with these new procedures.

Error Procedure• To identify the action to be taken the program

or hardware malfunctions• To be a step-by-step guide to correct the

error• To give advice on completing tasks manually

until the error is completed

Virus Detection Procedure • To ensure against loss of data or functions

Startup Procedure

• To specify steps to be taken to start up the system at the beginning of the day or after a breakdown

Backup Procedure

• To ensure against physical damage or accidental loss of data

The next part of implementation is to train the users in how to use the new system. Training is done using a variety of tools/methods:

FORMAL TRAINING

• External: College and TAFE institutions offer introductory short courses for package software with an emphasis on business applications.

• In-house: This is undertaken within the organisation and uses its system. This training is conducted by someone within the organisation or by an outside expert. An advantage of this type of training is that users become familiar with the equipment and procedures of the new system.

INFORMAL TRAINING• Written materials: these come in the

form of manuals or tutorials that accompany the software and hardware components

• Computer-based training: most major software packages provide a computer-based tutorial which leads the user step-by-step through the major features of the package

• General training: some large organisations run seminars and conferences to promote new or upcoming products. Designed mainly for computing professionals.

• User groups: many groups have been established to share and exchange knowledge

• On-line services: These allow access to user-pays information service from a computer terminal through a modem

The methods of training listed above normally cover the following areas

• Knowledge of the basic operations of the system • Use of the procedures needed to operate the

system such as start up, shut down and backup • Use of appropriate security techniques• Knowledge of health and safety legislation for all

users• Use of manuals for the software and hardware• Evaluation of courses to determine future needs.

SDLC: Evaluation and Maintenance Phase

EvaluationThe final phase of the system design life cycle is used

to evaluate the new or modified information system.

This phase involves monitoring, evaluating and maintaining the system.

The system is evaluated to determine how effectively it meets the objectives outlined in the preliminary investigation.

• The objectives are assessed in three aspects; performance; reliability and management of change:

Performance Evaluation• The system manager/analyst is concerned with

evaluating the efficiency and productivity of the technology. These characteristics can be measured and compared to the estimates indicated in the analysis and design phases.

• Efficiency is measured in terms of the time, cost and effort to complete a set task eg. measure how long it takes to print 18 pages of text.

• Productivity is concerned with the efficiency of the overall process

Efficiency and productivity could be evaluated in the following ways:

• Observing the system’s capacity to handle peak periods of demand

• Surveying staff to determine tasks completed during a set period, such as one day or one hour

• Timing the completion of a task• Calculating the total cost of one working day including

wages, electricity and materials and then comparing the same calculations with the old system

Reliability

• Many problems with a system only appear after a system has been implemented. These can include faulty equipment, inadequate training any incorrect procedures. Procedures such as security, backup and validation can be assessed in the following ways:

– Random shutdown of the system to determine if processes can be carried out manually

– Removal of selected files to determine if backup procedures are reliable

– Using computer professionals to test security measures

Management of Change

• An essential part of evaluating a system is by assessing the effects on job specifications, work environment, etc. These changes can be monitored in the following ways:

– Surveying staff reactions to the new system– Testing staff knowledge of the procedures– Monitoring frequency and cause of sick days– Assessing adequacy of training

Maintenance• System maintenance adjusts and improves the

system by having system audits, user feedback and periodic evaluations and by making changes based on new conditions

• Maintenance includes not only keeping the machinery running, but also updating and upgrading the system to keep pace with new products, services, customers, government regulations and other requirements.

Costs and Benefits of Information System

• A function in the evaluation phase is to evaluate the overall costs and benefits of the new system

Economic Costs

• Cost of new equipment• Cost of employment of design team and computer

professionals• Possible loss of production during the implementation

of the new system• Disruption to staff and possible redundancy pay outs• Cost of training

Economic Benefits

• Increased efficiency and productivity • Improved quality control • Improved customer service

Social Costs

• Repetitive strain injury• De-skilling of staff• Loss of employment• Stress due to change• Stress due to new technology

Social Benefits

• Increase in skill and job satisfaction• Health and safety reforms• Higher level of flexibility eg. flexible working hours