BIA 253 – Chapter 10 – IS Development – Flashcards

Systems Development (aka systems analysis and design), is the process of creating and maintaining information systems.

because many projects are never finished. of those that are finished, some are 200 or 300 percent over budget. - the difficulty of determining requirements - changes in requirements - difficulties involving scheduling and budgeting - changing technology - diseconomies of scale

"adding more people to a late project makes the project later". Brooks' law is true not only because a larger staff requires increased coordination, but also because new people need training. the only people who can train the new employees are the existing team members, who are thus taken off productive tasks. the costs of training new people can overwhelm the benefit of their contribution.

1. Systems Definition 2. Requirements Analysis 3. Component Design 4. Implementation 5. Maintenance

is the traditional process used to develop information systems.

during this SDLC phase, developers use management's statement of the system needs in order to begin to define the new system (for PRIDE, this statement is based on experience with the prototype).

here developers identify the particular features and functions of the new system.

the outcome of the previous phase is a set of approved user requirements, which become the primary input used to design system components.

developers implement, test, and install the new system.

over time, users will find errors, mistakes, and problems. they will also develop new requirements. the description of fixes and new requirements is input into a system maintenance phase. The maintenance phase starts the process all over again, which is why the process is considered a cycle.

in response to the need for the new system, the organization will assign a few employees, possibly on a part-time basis, to define the new system, to assess its feasibility, and to plan the project. typically, it's someone from the IS department.

approximates total costs and compares it to system value. ex: for PRIDE, this is a difficult assessment. it depends on the scope of the project.

this is very difficult to determine because it's hard to estimate the time it will take to build the system.

refers to whether existing information technology is likely to be able to meet the needs of the new system.

it concerns whether the new system fits within the organization's customs, culture, charter, or legal requirements. ex: will doctors be willing to use PRIDE?

they specialize in understanding business needs, strategies, and goals in helping businesses implement systems to accomplish their competitive strategies.

are IT professionals who understand both business and technology.

the important point is for users to have active involvement and to take ownership of the project throughout the entire development process.

the primary purpose of the requirements analysis phase is to determine and document the specific features and functions of the new system. for most development projects, this phase requires interviewing dozens of users and documenting potentially hundreds of requirements. requirements definition is thus, expensive and difficult.

1. determine requirements 2. approve requirements 3. role of a prototype

each of the five components is designed in the next stage. typically, the team designs each component by developing alternatives, evaluating each of those alternatives against the requirements, and then selecting among those alternatives. accurate requirements are critical here, if they are incomplete or wrong, then they will be poor guides for evaluation.

1. Hardware Design 2. Software Design 3. Database Design 4. Procedure Design 5. Design of Job Descriptions

once the design is complete, the next phase in the SDLC is implementation. tasks in this phase are to build, test, and convert the users to the new system. developers construct each of the components independently. they obtain, install, and test hardware. they license and install off-the-shelf programs; they write adaptations and custom programs.

1. System Testing 2. System Conversion

consists of sequences of action that users will take when using the new system. test plans include not only the normal actions that users will take, but also incorrect actions. the test plan should cause every error message to be displayed.

is an important career. PQA personnel usually construct the test plan with the advice and assistance of users. PQA test engineers perform testing, and they also supervise user test activity.

is the process of allowing future systems users to try out the new system on their own.

is often used for this activity because it implies the process of converting business activity from the old system to the new.

- pilot - phased - parallel - plunge

the organization implements the entire system on a limited portion of the business. the advantage of pilot implementation is that if the system fails, the failure is contained within a limited boundary. this reduces exposure of the business and also protects the new system from developing a negative reputation throughout the organization.

the new system is installed in phases across the organization. once a given piece works, the organization then installs and tests another piece of another piece of the system, until the entire system has been installed.

the new system runs in parallel with the old one until the new system is tested and fully operational. it is the slowest and most expensive because the organization incurs the costs of running both systems. users must work double time, to run both systems.

(sometimes called direct installation) with it, the organization shuts off the old system and starts the new system. If the new system fails, the organization is in trouble: nothing can be done until either the new system is fixed or the old one is reinstalled.

Maintenance is a misnomer, the work done during this phase is either to fix the system so that it works correctly or to adapt it to changes in requirements. 1. there needs to be a means for tracking both failures and requests for enhancements to meet new requirements.

patch

service packs - service packs are applied in much the same way that they apply patches, except that service packs typically involve fixes to hundreds or thousands of problems.

- the SDLC Waterfall - Requirements Document Difficulty - Scheduling and Budgeting Difficulties

like a series of waterfalls, the process is supposed to operate in a sequence of nonrepetitive phases. ex: the team completes the requirements phase and goes over the waterfall into the design phase, and on through the process. most commonly, when design work begins and the team evaluates alternatives, they learn that some requirements statements are incomplete and missing. At that point, the team needs to do more back and forth between requirements and design so many times that the project seems to be out of control.

when too much time is spent documenting project requirements.