Six Sigma
- A culture built on quality
- Uses a top-down approach
- Project leader is called a Black Belt
- Project members are called Green Belts
- Master Black Belts have worked on many projects and are available as a resource to project teams
Philosophy of Six Sigma (7 steps)
- Define the Problem
- Observe the Problem
- Analyse the Causes
- Act on the Causes
- Study the Results
- Standardize the Changes
- Draw Conclusions
Responsibility for Total Quality Management
- Full organizational support of management must exist
* Early commitment to quality from the analyst and business users
Structured Walkthroughs
- One of the strongest quality management actions is to do structured walkthroughs routinely
- Use peer reviewers to monitor the system’s programming and overall development
- Point out problems
- Allow the programmer or analyst to make suitable changes
Who is Involved in Structured Walkthroughs?
- The person responsible for the part of the system being reviewed
- A walkthrough coordinator
- A programmer or analyst peer
- A peer who takes notes about suggestions
The Top-Down Approach
- Top-down design allows the systems analyst to ascertain overall organizational objectives and how they are best met in an overall system
- The system is divided into subsystems and their requirements
Advantages of the Top-Down Approach
- Avoiding the chaos of attempting to design a system all at once
- Enables separate systems analysis teams to work in parallel on different but necessary subsystems
- Prevents losing sight of what the system is supposed to do
Modular Development
• Breaking the programming into logical, manageable portions or modules • Works well with top-down design • Each individual module should be functionally cohesive, accomplishing only one function
Advantages of Modular Development
- Modules are easier to write and debug
- Modules are easier to maintain
- Modules are easier to grasp because they are self- contained subsystems
Guidelines for Modular Programming
- Keep each module to a manageable size
- Pay particular attention to the critical interfaces
- Minimize the number of modules the user must modify when making changes
- Maintain the hierarchical relationships set up in the top- down phases
Testing, Maintenance, and Auditing
- The testing process
- Maintenance practices
- Auditing
The Testing Process
- Program testing with test data
- Link testing with test data
- Full system testing with test data
- Full system testing with live data
Program Testing with Test Data
- Desk check programs
- Test with both valid and invalid data
- Check output for errors and make any needed corrections
Link Testing with Test Data
• Also referred to as string testing • Checks to see if programs that are interdependent actually work together as planned • Test for normal transactions • Test with invalid data
Full System Testing with Test Data
- Adequate documentation in procedure manuals
- Are procedure manuals clear enough?
- Do work flows actually “flow”?
- Is output correct and do users understand this output?
Full System Testing with Live Data
- Comparison of the new system’s output with what you know to be correctly processed output
- Only small amounts of live data are used
Maintenance Practices
- Reduce maintenance costs
- Improve the existing software
- Update software in response to the changing organization
- Ensure channels for feedback
Auditing
• Having an expert who is not involved in setting up or using the system examine information in order to ascertain its reliability
• There are internal and external auditors
• Internal auditors study the controls used in the
information system to make sure that they are adequate
• External auditors are used when the information system processes data that influences a company’s financial statements
Client-Server Technology
- The client-server model refers to a design model that can be thought of as applications running on a network
- The client is a networked computer that uses small programs to do front-end processing, including communicating with the user
Advantage of Client-Server Model
• Advantage—greater computer power and greater opportunity to customize applications
Disadvantage of Client-Server Model
more expensive and applications must be written as two separate software components each running on separate machines
Cloud Computing
• Organizations and individual users can use: – Web services
– Database services
– Application services over the Internet
• Done without having to invest in corporate or personal hardware, software, or software tools
• A large collection of corporate users jointly bear the
lowered cost
• Realize increases in peak-load capacity
• Companies also hope to improve their ability to perform disaster recovery
Cloud Computing Trade-Offs
• One major decision is whether to use an external cloud
provider (public cloud) or an internal one (private cloud)
• Sometimes the decision to use a public cloud has to do with how critical it is for the company to strategically control data
• A hybrid approach, in which more critical data linked to strategic aims and corporate intellectual property are held in a private cloud, and less critical data for the same organization makes use of a public cloud, may be a solution
Factors in Choosing a Cloud Provider
• If a client of the cloud services provider is hacked, how will it adversely affect other businesses the cloud provider is hosting?
• How can your client be sure data are completely deleted from cloud systems when these systems are eventually decommissioned?
• Are the data architectures being used by the cloud provider standard and transparent so if the client wants to switch providers it would be realistic to do so?
proprietary programming structures in use, making transferring data out of the question?
• How can your client be certain that no one at the cloud provider or their staff working for other clients has access to your organization’s data?
