3. 1) Finding and fixing a software problem
after delivery costs 100 times more than
finding and fixing the problem in early design
phases.
- when one big Automobile companies
implements a recall for post delivery defect
the cost of repair can be many orders of
magnitude greater then the cost of fixing the
defect during the engineering or production
stage
4. 2) You can compress software development
schedules 25% of nominal, but no more.
Addition of people requires more management
overhead and training of people.
5. 3)For
every $1 you spend on development,
you will spend $2 on maintenance.
Successful products will have much higher ratios of
“maintenance to development”…..
Successful S/W product in commercial product domain such as
orical,microsoft application ,Unix operating system are very
long lived &can result in much higher ratios of maintenance
cost to development cost .
6. 4)Software development and maintenance
costs are primarily a function of the number
of source lines of code.
Generally true. Component-based
development may dilute this as might reuse -
but not in common use in the past.
7. 5)Variations among people account for the
biggest differences in software productivity.
Always try to hire good people. But we cannot always to that.
Balance is critical. Don‟t want all team members trying to
self-actualize and become heroes. Build the „team concept.‟
While there is no “I” in „team”, there is an implicit “we.”
8. 6)The overall ratio of software to hardware
costs is still growing. In 1955 it was 15:85; in
1985, 85:15.
The fact that S/W represent 85% of the cost
of most system is not so much a statement
about S/W productivity as it is about the
level of functionality being allocated to S/W
in system solution .
9. 7) Only about 15% of software development
effort is devoted to programming.
Many activities beside the coding are
necessary for the s/w project success like
testing ,planning ,project control ,change
management are equally important
consideration that consume roughly 85% of
resource
10. 8)S/W system & products cost 3 time as much per
SLOC as individual S/W programs .S/W- system
products (system of systems ) cost 9 time as much
A real fact: the more software you build, the more
expensive it is per source line
11. 9) Walkthroughs catch 60% of the errors.
Usually good for catching stylistic things; sometimes errors, but usually
do not represent the deep analysis necessary to catch significant
shortcomings.
Major problems, such as performance…are not caught.
12. 10)80% of the contribution comes from 20%
of contributors.