IT systems in organizations (SDLC and phases of SDLC ( (Maintenance:…
IT systems in organizations
Waterfall method is a traditional method approach which flows from the analysis through each stage to the installation. It is highly structured and allows for long term planning.
The problem with the waterfall method is that it lacks adaptability. large IT projects may take such a long time to develop that by the time the development stage has been reached the requirements identified in the analysis stage may have changed.
The agile model seeks to address some of the waterfall model's weakness by allowing greater adaptability. The same SDLC stages are applied to only a small part of the problem at a time.
The problem with the agile model is that solutions can be piece meal and for very large projects the lack of an initial goal and design for the whole project can result in a less efficient design.
SSADM is a methodology that focuses primarily on the analysis and design stages of the SDLC. There are 7 stages.
PMBOK is not specific to software development projects. Its techniques can be used to manage virtually any project from building a house to designing an aircraft.
PMBOK divides the project life cycle into five stages called process groups.
Prince 2 is the standard project management methodology used by the UK government.
Prince 2 divides the life cycle into stages. Each stage is broken into levels which describe the type of work performed.
SDLC and phases of SDLC
Maintenance: updates and changes made to a system to fix bugs, improve performance, or add new features.
Installation: installing the software and any necessary hardware, usually at the client’s organization. This may involve removing the old system and transferring any required data from it to the new system.
Testing: ensuring that the system functions correctly
Development: the creation of the system
Design: the planning of a solution to meet the needs of the client
Analysis: An investigation of the current system, the needs of the client, and the possibility of creating a new system.
Off the shelf software and bespoke software
Off the shelf software is widely available for general purchase from software vendors.
Bespoke software is created specifically for a single organization. Usually the organization hires a software development company but it may also have its own software developers in the house. The developers analyse the organization's needs and design software specifically to meet them.
A legacy system is a computer system that is no loner available for purchase or is no longer supported by the manufacturer.
Changeover is the process of introducing a new system whilst retrieving an old system. There are three ways in which this can be done.
Direct changeover is when the old system is removed and the system is put into place immediately.
Phased changeover is when you gradually switch from the old system to a new system with some parts switching before others.
Parallel changeover involves introducing the new system at the same time as running the old system.
Emulation and virtual machines
One solution to using legacy systems in a modern environment is to employ a virtual machine which creates a virtual computer running inside a window.
Alpha testing is performed to verify that the software works according to the requirements specification and the design documentation.
Versions of the software are normally given to a relatively small group of users with the aim of detecting any remaining bugs and testing the software's usability under real world conditions.