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1.1 Systems in organizations (10 hours)
Some Example of different Types of Systems
1.1.1 Identify the context for which a new system is planned
Teacher Notes
Before a system is designed, it needs to be identified what the system should do. To do this is the job of the systems analyst. He looks at the existing system and tries to observe how it works. This can be done using surveys, interviewing users, observing them or by tracing how information is handled by looking at the documents produced by it.
For this, the systems analyst has to factor in a number of things: what existing infrastructure from the existing system can be used? What requirements on hardware and software will the new system have? Are there any ethical issues resulting, for example will the new system make people unnecessary, leading to loss of jobs?
Data Collection
1.1.2 Describe need for change management
Teacher Notes
Teacher Notes
Without a proper plan on how the new system will be implemented once it is designed the change from the old system to the new one will not be successful. Many factors will need to be regarded:
1.1.3 Outline compatibility issues resulting from situations including legacy systems or business mergers
Without a proper plan on how the new system will be implemented once it is designed the change from the old system to the new one will not be successful. Many factors will need to be regarded:
- 1Legacy System – In computing, a legacy system is a technology, computer system, or application program, that may or may not be supported or available for purchase any more.
- 2Merger – A combination of two things, especially companies, into one
1.1.4 Compare the implementation of systems using a client’s hardware with hosting systems remotely.
Software as a Service (SaaS): The client does not run its own computer system to handle operations, but lends servers from the software manufacturer that are managed and maintained by the software manufacturer. A great example is SAP.
Advantages
Disadvantages
1.1.5 Evaluate alternative installation processes.
Teacher Notes
1.1.6 Discuss problems that may arise as a part of data migration
Teacher Notes
File formats are another worry when concerning the issue of data migration and compatibility. Having the ability to read and write data in the same manner as before, following an improvement or change in a system, is almost certainly the fundamental aspect which is taken into consideration.
Incompatible file formats
Incompatible data structures
Changed units leading to misinterpretation (new system interprets temperature in °C instead of °F)
1.1.7 Suggest various types of testing.
Teacher Notes
esting is very important in developing a computerized system, as it tries to ensure that the system works as expected. A system that does not work as expected (it is buggy) greatly reduces productivity and end user satisfaction.
Testing is usually done in two stages: before the system is delivered and after it has been set up.
Testing in the first stage is often referred to as Alpha testing, while testing in the second stage is often referred to as Beta testing.
Alpha testing involves the engineers who develop the system testing it with data similar to real data while beta testing involves testing by real users with real data.
User focus
1.1.8 Describe the importance of user documentation.
Teacher Notes
User documentation is a crucial part of a system as it is the document that explains the working of the system to the user. A well-made user documentation guides the user through using the system and thus increases productivity. If the user documentation is simple, system implementation can happen faster because users require less training to learn how to use the new system.
Users are non-technical people, they only need to know how to use the system. Therefore, the user documentation does not involve detailed explanations of how the system works.
User documentation supports computer system users, including both hardware and software. Good user documentation can ensure that users are quickly able to adapt to a new system. Documentation is an important part of software engineering. Types of documentation include:
Different Types
1.1.9 Evaluate different methods of providing user documentation.
Teacher Notes
Help files: Files supplied together with the system. They can usually be called up with a button in the system.
Advantages
Disadvantages
Online support: Special web service hosted by the system’s developer to provide user documentation.
Printed manuals: manuals printed on paper and supplied together with the system.
1.1.10 Evaluate different methods of delivering user training.
Training staff in using a new system is very important as productivity greatly depend on how familiar users are with a system. Therefore good user training is an essential part of introducing a new system.
Self-instruction: users reading a manual or watching a tutorial, or randomly doing something in the system to figure out how it works. This type of training is only suitable for experienced computer users as they are more confident to start using an unfamiliar system alone to figure out how it works.
Formal classes: users sitting in a classroom listening to an instructor who shows and explains how to use the system. This type of training is useful to train large amounts of staff as it is effective and relatively cheap, but if the size of the classes is too big, there is little time to deal with individual problems and questions.
Remote/online/personal training: an instructor training a single user either by being in the same room or by some kind of remote connection (Skype, chat). This is the most effective way of training as training can be suited to user’s needs and abilities, but is very expensive compared to other types of training.
System Backup
1.1.10 Common Causes of Data Loss
1.1.12 Outline the consequences of data loss in a specified situation.
Data Loss in School
If a school loses its online information, it can lose schedules, grades, personal information about who works there and who studies there, and future plans for the school.
1.1.13 Describe a range of methods that can be used to prevent data loss
1.1.12 Outline the consequences of data loss in a specified situation.
Software Depolyment
1.1.13 Describe strategies for managing releases and updates
Students should be aware of a variety of ways in which updates and patches are made available and deployed. This includes automatic updates received on a regular basis online
1.1.13 Describe strategies for managing releases and updates
1.2 System design basics (10 hours)
Components of a computer system
1.2.1 Define the terms: hardware, software, peripheral, network, human resources.
1.2.2 Describe the roles that a computer can take in a networked world
1.2.3 Discuss the social and ethical issues associated with a networked world.
System design and analysis
1.2.4 Define the terms: hardware, software, peripheral, network, human resources.
1.2.5 Describe methods of obtaining requirements from stakeholders.
1.2.6 Describe appropriate techniques for gathering the information needed to arrive at a workable solution.
1.2.7 Construct suitable representations to illustrate system requirements.
1.2.8 Describe the purpose of prototypes to demonstrate the proposed system to the client.
1.2.9 Discuss the importance of iteration during the design process
1.2.10 Explain the possible consequences of failing to involve the end-user in thedesign process.
1.2.11 Discuss the social and ethical issues associated with the introduction of new IT systems.
Human interaction with the system
1.2.12 Define the term usability.
1.2.13 Identify a range of usability problems with commonly used digital devices.
1.2.14 Identify methods that can be used to improve the accessibility of systems.
1.2.16 Discuss the moral, ethical, social, economic and environmentalimplications of the nteraction
between humans and machines.
SDLC Lesson Overview
Systems Development Lifecycle |
Building a house |
Investigation/Feasibility study Investigate systems currently being used - benefits/limitations requirements for the new system
Create report on Purpose of the new system System scope/what it will cover Deficiencies in the current system User requirements Costs and benefits of the new system |
Investigate What kind of house is needed? How will the house be used (family, young couple, retired, young single)?
How big is the plot of land? Does the land have Gas. Water, electric? What rooms/levels are required? Likely cost to build the house Benefits of the house |
Analysis - Detailed User Requirements
Detailed list of Input requirements Output requirements Processing and calculations required |
Detailed requirement list
Rooms Size of rooms Requirements in each room Type of building
|
Design the Systems
Work out: Data Flow Diagrams Entity Relationship Diagrams Attributes Data Dictionary Program Specifications |
Design the House
Work out: House plan List of parts required Plan build of house, what needs to be done in what order |
Develop the system
Write the programs according to the design |
Build the house
Build the house according to the house plans and project plan |
Test the system
Functional test test each program
System test Test programs link together correctly (whole system test) |
Make sure everything works in the house
Test wiring and electrics Test plumbing Test heating Test appliances in the kitchen etc |
System Documentation
Produce: Technical Documentation User Documentation |
House Documentation
Land registry documents Contract on sale of house Searches Instructions on central heating/appliances |
Systems Implementation Train the users in how to use the system Hand over the system to the users |
New Owners move into the house |
Maintenance - Monitor & review Make sure system is running okay Report and fix any bugs in the system |
On Going Maintenance Report any problems back to the builder Builder fixes problems |
Lesson 1( 1.1.1 -.1.1.3 ) ( SDLC )
Learning Objectives
Google Doc explaining the different stages of SDLC - Open and Take copy clicking here
Lesson 1 Class Activity
Select a real life example from the list of software system types below that has been a disaster.
Provide a brief overview of the disaster and the reason why it was a disaster. You will report your findings in the next class.
Lesson 2 ( SDLC )
Learning Objectives
Review Questions
When an organization needs new software what are the main options available ?
Lesson 3 ( testing ) ( SDLC )
Learning Objectives
Review so far
- 1Legacy System – In computing, a legacy system is a technology, computer system, or application program, that may or may not be supported/available for purchase any more.
- 2Merger – A combination of two things, especially companies, into one
Activity 5-10 min Class discussion on advantage and disadvantageous of
1 off the shelf software and
2 Custom / Bespoke S/W
Task find a SW disaster and share with class 5 mins
Stage 1 Analysis and User Requirements
What is the output of this stage ?
What is the big weakness in the waterfall method to s/w development?
Waterfall - Sequential flow in one direction thus waterfall. In real life failures to correctly capture user requirements can be a disaster as the costs to change after the coding / development has started is huge
Incremental Models
First step create part of the system with limited functionality. Example in patients record system first step provide view only access to patient records.
Stage 2 Add Amend update
Open Source would be a good example of the incremental approach
Iterative Model
First step show interface to system options available reports etc ( do not add the actual functionality until end user approved). We are therefore clarifying the user requirements.
The user can request change with minimal additional time and cost being added to overall project budget
What is prototype ?
Similar to Incremental
Agile Approach
Implementation
We have discussed off the shelf S/W and Bespoke
We have looked at these stages in the waterfall methodology
1 )Systems Analysis and defining user requirements ( Methods of data gathering).
2 )Approaches to setting the system live.
Without a proper plan on how the new system will be implemented once it is designed the change from the old system to the new one will not be successful. Many factors will need to be regarded:
Lesson 4 Overview ( SDLC )
Learning Objectives
Lesson 5 ( User Focus Documentation and Training )
Learning Objectives
LInk to slide Show click here
Review Unit Test Past Papers
resources
Legacy System Definition
A legacy system is a computer system that is no longer available for purchase or is no longer supported by the manufacturer. A legacy system might be just a few years old, or it could be decades old. Some legacy systems may operate on (and even require), certain very old hardware which is no longer available. Others may only run on older operating systems and not be compatible with modern versions. Sometimes the manufacturer of a legacy system no longer exists, and in other cases the manufacturer has dropped support in favour of more recent products. This usually means updates and security fixes will not be available for the system, which can be a significant problem for organisations.