Lesson 1.19

spiral method

A modern approach to building information systems uses a spiral method, where each phase is done in sequence, then that sequence is repeated one or more times, with each phase done more thoroughly each time.

Spiral method

An IS developer using the spiral method may use multiple iterations of the design cycle phases to build the same computer system

Project managers

Coordinate system development during all phases of the SDLC by setting goals and timelines for developers based on what users or clients need.

Project Manager

Sets deadlines and milestones in the development of a new smartphone app and ensures that the app is delivered to the client on time. A project manager sets goals and timelines during system development.

Technical support specialists

Work with users to solve problems related to system operation. Error reports from users often inform future bug fixes, improvements, and design changes during the testing and analysis phases.

product manager

Works with prospective clients and users to determine the next features to add in a mobile banking app. A product manager collects information about user requirements and uses this information to guide future system development.

Product managers

guide the development of new systems during the design and analysis phases by learning what types of product users or clients need and whether developers can meet these needs.

Quality assurance (QA) engineers

test and analyze systems during the implementation and testing phases to minimize the number of bugs before deployment.

User experience (UX) engineers

work with users and developers during the design phase to design systems that are intuitive and easy to use.

QA Engineer

Designs tests to make sure that an e-commerce website does not fail during a busy shopping season. A QA engineer is responsible for testing information systems to minimize the number of bugs or failures.

The waterfall method allows phases to be performed simultaneously. For example, implementation can begin while a system is being designed.

False Each phase in the waterfall method must be completed before moving on to the next phase.

Does the spiral method allow phases to be performed simultaneously? For example, implementation can begin while a system is being designed.

No In the spiral method, the phases are still executed sequentially. One phase can only begin after the previous phase has completed.

The testing

phase checks that the system functions properly and meets or exceeds the requirements.

Project managers coordinate the entire SDLC process and set goals and deadlines.

1. Although developers are involved in all processes of SDLC, many other types of professionals collaborate during SDLC. 2. Product managers collect information from clients about what problems a product needs to solve. 3. UX engineers design user friendly systems. QA engineers design tests that minimize bugs and failures. 4. Technical support specialists help users with errors and can contribute information toward future bug fixes and design. 5. Project managers coordinate the entire SDLC process and set goals and deadlines.

Systems development life cycle (SDLC) phases include analysis, design, implementation and testing, done using a waterfall or spiral process.

1. Analysis determines the goals and requirements for the system. Design determines the specifics of how to build the system. 2. Implementation builds the system according to the design. Testing checks that the system functions properly and meets or exceeds the requirements. 3. The waterfall method executes the SDLC phases sequentially. Each phase begins after the previous phase is completed and reviewed. 4. The spiral method is an example of iterative system development because all of the phases are repeated until the final system is complete.

In the computer system example above, how many computers were used in the implementation of the first iteration?

10 A smaller computer system with 10 computer was used in the first iteration to design, build, and test the system before building the full system. Testing of the system in that iteration informs the analysis and design for subsequent iterations.

Waterfall method

An IS developer has the following problem: Develop a computer system for a small charter school with 80 students that allows students to register for classes, send emails, and turn in classwork. Using the waterfall development method, the developer would follow the analysis, design, implementation, and testing phases, in that order.

In the computer system example above, if the computers have trouble connecting to the system from certain locations on campus during the testing phase, at what phase will the system design life cycle restart?

Analysis Each iterations starts at the analysis phase. After the first iteration, the analysis phase often determines the strengths and weaknesses of the previously built system.

How many SDLC iterations are used in the spiral method?

As many as needed The number of iterations depends on how many iterations the developer needs to produce a completed system. More complex systems may require more iterations.

Collaboration in system development

Building an information system often requires collaboration between developers and many other individuals across the SDLC phases.

Implementation

Building the system according to the design. In the implementation phase of constructing a toaster oven, a developer builds the system according to the design choices.

Testing

Checking that the system functions properly and meets or exceeds the requirements of the system. In the testing phase of constructing a toaster oven, a developer checks that the system functions by testing the oven's ability to perform the toast, bake, and broil operations, fit a small pizza, and not burn or melt the oven materials.

UX engineer

Designs the color scheme, icons, and layout of an educational website so that a disabled person is able to use the website easily. A UX engineer is responsible for designing information systems that are user friendly.

Analysis

Determining the goals and requirements for the system. In the analysis phase of constructing a toaster oven, a developer determines the goals and requirements: The toaster oven should be able to toast, bake up to 500° F, and broil. The oven should be able to hold a small pizza. The oven materials cannot burn or melt during operation.

Design

Determining the specifics of how to build the system. In the design phase of constructing a toaster oven, a developer determines the specifics of the oven including the size of the oven, the materials to build the oven with, the wattage of the oven, etc.

If a problem is found during the testing phase, the system development life cycle must restart, and all phases are repeated.

False Small bug fixes do not require repeating the entire system design life cycle. Ex: For a laptop that can't connect to the network, the fix might be to enable WiFi on the laptop, which does not require repeating the analysis, design, and implementation phases.

Technical support specialist

Helps a user troubleshoot errors during installation of a new operating system and discovers a bug in the process. Technical support specialists work closely with users to solve problems that occur when using or installing a system. Information reported by users is often valuable for future improvements.

system development life cycle or SDLC

In information systems, systems are built using a series of phases known as the system development life cycle or SDLC. SDLC can also refer to the software development life cycle, or the process by which programs and other software is developed. The SDLC phases include analysis, design, implementation, and testing.

An IS developer using the spiral method to develop the computer system for a small charter school may use two iterations to incrementally analyze, design, build, and test the system.

Iteration 1 - Preliminary Iteration Analysis: -Need computers for all 80 students -Need a central database for student information and assignments *Design: 10 desktop computers per classroom, connected using a LAN connection with a single router. *Implementation: Build the system for a single classroom with 10 desktop computers. *Testing: Connect desktops to the network and ensure each computer can communicate with central database. Iteration 2 - Final Iteration Analysis: Determine the strengths and weaknesses of the system built in the previous iteration. -Desktops and LAN connections were not mobile, which limited students ability to use the computer system. -Define new requirement that computers must have access to school network from anywhere on campus. *Design: Refine the system design by replace desktops with laptops and using a wireless network. *Implementation: Build the revised system consisting of 80 laptops for all students. *Testing: Connect laptops to the network and ensure all laptops can communicate with the central database. Move laptops around campus to ensure connection quality. The system development could consist of numerous iterations of the SDLC phases. Additional testing and analysis can involve student input about what is liked and disliked about the system, ease of submitting assignments, etc.

waterfall method

Method that only performs one iteration of the SDLC phases. The waterfall method executes the SDLC phases one time.

Spiral Method

Method that performs multiple iterations of the SDLC phases. The spiral method is iterative because the SDLC phases are performed multiple times until the system is complete.

waterfall method

Some developers build an information system via a waterfall method, where each phase is done in sequence, entirely completing one phase before moving to the next phase.

A company makes three prototypes for a new Bluetooth speaker.

Spiral The development of the Bluetooth speaker goes through three iterations, meaning the developers are using the spiral method to successively test, analyze, and improve the speaker design.

After initially giving a trial version of a new photography software to a few users, the company gets feedback that most of the users cannot figure out how to use the zoom function.

Spiral The spiral method allows the company to do additional analysis based on the users' feedback. The feedback can then influence the next iteration of the design.

The analysis phase comes before the design phase.

True A system is designed according to the requirements that stem from the analysis phase. Once the analysis is complete, the next phase is design.

After a single round of testing, a mobile application is deployed to users.

Waterfall A single round of testing before deployment indicates the waterfall method is used because the waterfall method executes each phase once.

A company is tasked with developing a new satellite to orbit the earth to monitor weather patterns and must have a complete budget for the design before building the satellite.

Waterfall In order to have a budget for the satellite design, the design must be complete, so a waterfall method is needed. Additionally, once deployed to space retrieving the satellite to redesigning is prohibitively expensive.

The analysis

phase determines the goals and requirements for a system.

The design

phase determines the specifics of how to build a system.

The implementation

phases builds the system according to the design.