Lecture 3 - History of ISD and Current practice and problems

Question 1

What do information systems consist of?

Answer 1

Data, People, hardware, software and telecommunications

Question 2

IS and competetive forces - mention the five forces

Answer 2

Bargaining power of suppliers, bargaining power of buyers, threat of substitute products, potential threat of new entrants.

Question 3

What is the four essential difficulties in ISD?

Answer 3

Complexity, conformity (overensstemmelse), changeability, invisibility.
(Avison et Fitzgerald, 2006)

Question 4

Describe the pre-methodology era.

Answer 4

(1950+)
No explicit ISD-method existed.
Developers lacked communication skills.
(Avison et Fitzgerald, 2006)

Question 5

Describe the early methodolgy era.

Answer 5

1960+
Development of SDLC (software development life cycle)
Waterfall Model
No iterations and no looking back

Question 6

Describe the methodolgy era.

Answer 6

1970+
Evolution of SDLC led to Merise, SSADM, Yourdon Systems Method.

New approaches/methologies based on different paradigms: strategy, participation, prototyping (incremental), data analysis, etc.
(Avison et Fitzgerald, 2006)

Question 7

Describe the post-methodology era

Answer 7

2000+
Also called reflecting era.
Methodologies were used in a reflected way, and critique raised againts using methods: productivity, complexity, etc.
(Avison et Fitzgerald, 2006)

Question 8

Describe the contingency approach.

Answer 8

Is where a structure is presented but stages, phases, tools, techniques, and so on, are expected to be used or not (or used and adapted), depending on the situation => the choices are context dependent (project size, importantsness etc.)
(Avison et Fitzgerald, 2006)

Question 9

What are some of the main risks when following the Waterfall approach?

Answer 9

Fordi testfasen først ligger til sidst vil mange fejl og mangler først blive opdaget her, hvilket ofte ikke kan løse med mindre justeringer, men vil kræve en omlægning af både systemkrav design ovs., hvilket kan være meget tids- og omkostningskrævende for et projekt.
(Royce 1979)

Question 10

What are the five steps that Royce (1979) recommends when making system development to minimize the risks of failing? (Looks somehow like a modified waterfall model, that includes small iterations - see article for illustrations)

Answer 10

Step 1: Program design comes first
Step 2: Document the design
Step 3: Do it twice
Step 4: Plan, control, and monitor testing.
Step 5: Involve the customer (has to be committed to the process before the final delivery)
(Royce 1979)

Question 11

What is the main difference between the Waterfall Model and the Spiral Model?

Answer 11

The Spiral Model is more risk-driven of nature, where the Waterfall Model is more document-driven (Documents are used as a completion criteria for early requirements) (Document driven causes the stages to be in the wrong order.)
(Boehm 1987)

Question 12

What is the primary advantage of the Spiral Model?

Answer 12

The model has many options consisting of good features of existing software process models (Boehm 1987)

Question 13

What are the main difficulties of the Spiral Model?

Answer 13

The primary challenges involve matching to contract software, relying on risk-assessment expertise and the need for further elaboration of the spiral model steps. (Boehm 1987)

Question 14

Why are software process models important?

Answer 14

They provide guidance on the order (phases, increments, prototypes, validation tasks, etc.) in which a project should carry out its major tasks. (Boehm 1987)

Question 15

Give an example of the risk resolution in the different rounds? (Spiral Model)

Answer 15

a. Surveys
b. Analysis
c. Structured interviews with software developers and managers
d. Benchmarking
e. Analysis of a prototype
(Boehm, 1987)

Question 16

Why are software process models important?

Answer 16

Primarely because they provide guidance on the order in which a project should carry out its major tasks. (Boehm, 1987)