1. Investigating and Improving a COTS-based Software Development Process
Morisio, Seaman, Parra, Basili, Kraft, Condon
icse 2000
This paper develops a process model for cots-based software development by investigation among 15 COTS projects performed at FDD.

2. Outline Background Study design Results of the study
SEL and Strawman process
Study design
Strutured interview
Results of the study
Differences between COTS projects and traditional projects
Disadvatage of COTS projects
New proposed process model
Conclusion

3. Background
Software Engineering Laboratory (SEL), known for empirical study of software development practice, provides guides to NASA/GSFC projects.
SEL developed a process for COTS-based development for FDD – Strawman process
15 COTS projects are studied to evaluate and improve the process model
SEI provides guides to NASA more than 20 years. In 80s and 90s there is trends to reuse and cots-based developemnt in FDD, SEI decided to provide guildelines gor this process.
In 1995, initial strawman process defined according to experience from the outside. Then are reviewed by the software engineers in FDD and modified, the resulting strawman process is like this:
At the same time as this strawman process is devloped, several cots project are done at fdd. So SEI decided to perform a observational study for these projects, look at what are done in practice, is it same as the strawman process, and how improve the process.

4. Strawman process Phase Major Activities Products
Management Check-points
Requirements Analysis and COTS Identification
Requirements analysis
COTS survey and preliminary evaluation
Requirements
Strawman high-level architecture
Candidate COTS
System requirements review
Architecture definition and COTS Selection
COTS evaluation
Requirements modification to use existing COTS
Prototyping
Modified requirements
System architecture
Final COTS
System design review
System Integration and test
Use-case implementation
Independent testing
Delivered system
Uer demonstrations
Operational readiness review
Tchnology Update and System Maintenance
Evaluation of new products and technology
Enhanced system
User demonstrations

5. 3 Types of COTS-based Systems
Defined by Carney:
Turnkey systems: Build around a suite of commercial products such as Microsoft Office. Customization does not change the nature of the initial product.
Intermediate systems: Built around one COTS but integrate other (also developed in-house)
Other: Built on several COTS with same importance.

6. Study of the Actual Process
Structured interviews using the GQM approach
25 representatives from 15 projects in 2. and 3.category of Carney definition.
Two study teams:
Interviewer
Scribe
Analysis by constant comparison method

7. Differences between COTS projects and traditional projects
More effort on requirements, test and integration, less on design and coding.
3 types of differences:
New activities: COTS selection, COTS familiarization, vendor interaction
Reduced activities: coding, debugging, unit testing.
Modified activities: design, architecture issues (compatibility, configurability)
The result of the analysis found cots projects must follow a process that is quite different from traditional projects
In design, focus is on how to fit pieces tigether rather than the internal structure of the modules.

8. Disadvantage of COTS projects
Dependence on vendor: functionality available, the schedule for release, the reliability level, documentation…
Flexibility in requirements: COTS drives the requirements at least to some extent
A trade-off between disadvantage and the benefits of COTS
The study also found the ad and disad of cots project, ad ie everyone know, reduced time to market, cost, effort, but not all the project can use cots, because cots project must consider some issues,

9. New COTS Process Main phases are: Requirement Design Coding
Integration

10. New process model Vendor
Requirements
Design
Coding
Integration
COTS specific activities
Package
Identification
Evaluation/
Selection
Identify
Glueware and
Integration
Requirements
Write
Glueware
And
Interfaces
Integration
and Test
Target system
Installation
and Acceptance
Test
Requirements
Review
Design
Review
Requirements
Analysis
Non-COTS
Design
Non-COTS
Coding
The difference with strawman is mainly on requirements and design phase, so This paper only give more description to these two phases.
Customer

11. Requirement Make versus buy decision I Requirement definition
Consider trade-off between non-technical issues and disadvantages of COTS project
Requirement definition
COTS identification and selection
COTS familiarization: learn about COTS
Feasibility study
describe the product on a high level, an effort estimation, a risk assessment model. Both for COTS and non-COTS.
Make versus buy decision II
The result is the product variant that will be developed
Requirements Review
Requirements phase includes these activities, they are in a logical order, in practice, they may be performed concurrently or iterative.
I only get all the possible situations, not final desicion.
The goal of requirement definition is to guide identification og COTS. COTS are identified and evaluated by vendor documentation, reviews, previous experience. Reduce the number of candidates to two or three.
Feasibility study is the futher evaluation of COTS, it also evaluate non-cots solution. One such description shoud be given to each product variant with COTS and without COTS.

12. Design
Definition of architecture and integration issues at lower level of details
Decision on glueware
Design Review
Some high level design in requirement phase, in desiogn phase activities go more deeper, more detailed. All the effort should be concentrated on the product variant selected by requirements phase.
Define the integration of cots and new developed componets, shoud make decision on glueware.

13. New Roles COTS Team Interface with vendors At the organization level
A repository about COTS
Interface with vendors
At the project level
Build partnership with vendors

14. Conclusion
COTS-based processes differ considerably from traditional software development
New activities
Reduced activities
Modified activities
Disadvantage of COTS projects:
Dependence on vendors
Flxibility in requirements
The new process is defined
Requirements and design phases are most challenging