System Life Cycle Flashcards
Change over methods
Phased conversion - a module at a time can be converted to the new system in phases until the whole system is transferred (1).
- -+Advantages: IT staff can deal with problems caused by a module before moving onto new modules (1)
- –Disadvantage: Is only suitable for systems consisting of separate modules (1)
Pilot conversion - this method is ideal for large organisations that have lots of locations or branches where the new system can be used by one branch and then transferred to other branches over time (1).
- -+Advantage: Implementation is on a much smaller and manageable scale (1)
- –Disadvantage: Takes longer to implement the system in all the branches (1)
Direct changeover- Stop using the old system one day and start using the new system the next day(1)
- -+Advantage: Requires fewer resources (people, money, equipment) and is simple, nothing goes wrong (1)
- –Disadvantage: Element of risk particular if the hardware and software are cutting edge (1) if the system fails then it an be disastrous to the business (1).
Parallel changeover- old ICT system is run alongside the new ICT system for a period of time until all the people involved with the new system are happy it is working correctly (1)
- -+Advantage: Used to minimise the risk of introducing a new ICT system (1). The old system is then abandoned and all the work is done entirely on the new system (1).
- –Disadvantages: Lots of unnecessary work (as the work is being done twice) and is therefore expensive in peoples time (1). It also adds to the amount of planning needed for the implementation (1)
Investigation Techniques
Interviews – a one to one conversation between managers, discussing the current strengths and weaknesses of the system.
- -+Advantage: In-depth answers.
- -+Advantage: Follow on questions.
- –Disadvantage: Needs skilled interviewers to get the correction information out of people.
- –Disadvantage: Time consuming.
Observation – sit and watch someone do their job. It’s over-seeing staff in operation of the system.
- -+Advantages: Detect issues which are difficult to explain.
- -+Advantage: Observe shortcuts.
- –Disadvantage: Time consuming.
- –Disadvantage: People act different when being observed.
Questionnaires – Pre-defined set of questions which are sent out to people.
- -+Advantage: Can be sent to a large number of people.
- -+Advantage: Easy to analys.
- –Disadvantage: Response rate low.
- –Disadvantage: Trust rate low.
Document Inspection– studying the paper based information produced by the company at the moment.
- -+Advantage: Allows one to see what information is currently held and the way is it communicated between different departments or customers and the company
- -+Advantage: Spotting trends.
- -+Advantage: You can refer back.
- –Disadvantage: Out of date (historical)
- –Disadvantage: Out of office (don’t disrupt operation of company)
Maintenance Techniques
Perfective maintenance (1)- improving the performance of the software (1). ---Examples: configuring the network management software to improve performance such as improving access times to data, speed at which reports ae produced etc. (1) software may need to be modified to improve the user interface upon feedback from users who are finding it more difficult to use than it needs to be (1). Developing on-line tutorials and more help screen to help new staff learn the software (1). The software provider provides upgrades which will improve the performance of the software (1)
Corrective maintenance (1)- bugs in the software which were not discovered during testing may need correcting —(1). Example: a piece of software may crash when being used with another piece of software (1). A piece of software may crash when used with a particular item of hardware (1). Software may present a security risk which needs correcting (1). Problems with reports not being printed out properly (1)
Adaptive maintenance (1)- software may need to be changed owing to the changing needs of the business or organisation ---(1). Example: software may need altering so that it is more flexible in supplying the manager with information which was not envisaged at the time of development (1). Changed to values such as the percentage of VAT or changes to income tax rates will result in changes to the software (1). The organisation expands so the software needs to be altered so it is able to cope with an increased number of users(1). Adapting the software to work with newly developed operating systems software or new hardware (1). A new virus threat/ hacker threat means the software will need to be adapted to protect against this (1)
Maintenance – Why People become dissatisfied
—The full range of user requirements has not been met, so the system does not live up to user expectations.
—Change in business needs means system cannot deal with new demands placed on it.
—Failure to supply users with the information they require
—User interface causes many user problems with increased help-desk use.
—Problems with the software or system crashing owing to a lack of rigorous testing.
—Network performance or speed of access to stored data becomes unacceptable as more users are added to the system
—Modifications to the system are needed regularly and the system needs replacement with a new one
—Too much time is spent updating to the new system
—The cost of user support is too high
—There are security breaches which were not envisaged when the system was first developed
—Speed- hard drive filling up – demands of software
—Fashion- hardware satisfaction
—Compatibility issues using newer versions of software
Feasibility Study: Definition
Consider the request for a new system from different perspectives (usually economic, operational and technological) to determine whether it is worth the organisation under taking the project.
Feasibility Study: Factors
User requirements
- –Analyse investigation.
- –Aims – Over all outline of project.
- –Objectives – Specific aspects the project must include.
Definitions of the scope of the present system
—Outline the current system, what it does and the current limitations.
Source of data
- –Identify where source of data is coming from (internal documents, external organisations, government etc).
- –Methods of data capture (data input sheets, barcode readers, online, etc)
Major data processing functions and processes
- –Data flow diagrams
- –High level contextual diagrams
- –Over view of the entire system.
- –Decision table.
Identification of problems with the current system
- –Technical problems (tasks not being properly completed, errors occurring, files not saving)
- –Usability issues (looking through many folders to find file, password access, frequently used files not accessible).
Cost benefit analysis
—Cost in terms of human resources, consulting fees, training requirements, hardware upgrading & license and fees.
Analysis of current hardware and software
- –Will anything need to be compatible
- –What will be compatible
- –Consider technical issues
Operational issues
- –Impact of day to day work
- –What training will be required
- –Will you need to re-structure
- –Security
Potential Improvements
- –Benefits of the system
- –Conclusion – is it worth it?
Design
—Creating the design specification for software
—Design of input methods. This will include the designs of forms (data capture/ on-screen/ switchboard) used to input data
—Design of processes – queries, macros, calculations
—Design of output- report/ specialist documents such as invoices, payslips etc.
—Design of data and file structures that will allow a usable system to be built. This will include the design of fields and table structure for a relational database.
—Design of information systems that will allow user to get relevant information out of the system, which will allow them to make appropriate decisions (DFD’s/ ERD’s)
—Design of networks and transmission issues such as topology, type of cable, protocols etc.
Personnel issues. Staff will need training and departments reorganising, skill level of the user.
—Security processes and procedures i.e. registering with the information commissioner, where data is stored, access levels, design of backup procedures, etc.
—Design of house style/ethos
Evaluation
Identifying any problems or shortcomings of the new system a few weeks after implementation
—Checking that the original user requirements have been fully met by the systems
—Assessment of how happy the clients are with the development of the new system
—Setting up a review cycle so that the system is checked periodically to make sure that it is still meeting requirements
—Methods of avoiding post implementation cost
—Gathering information for the evaluation report including quantitative test, error logging interviews, questionnaires
