14-05-2012, 04:50 PM
Software
16492_Lecture1.pdf (Size: 73.67 KB / Downloads: 27)
: If you have to write a 10,000 line program in C
to solve a problem, how long will it take?
• Answers: generally range from 2-4 months
• Let us analyze the productivity
– Productivity = output/input resources
– In SW output is considered as LOC
– Input resources is effort - person months; overhead cost
modeled in rate for person month
– Though not perfect, some productivity measure is
needed, as project has to keep it high
Software
Student
• Developer is the user
– bugs are tolerable
– UI not important
– No documentation
Industrial Strength
• Others are the users
– bugs not tolerated
– UI v. imp. issue
– Documents needed for
the user as well as for
the organization and the
project
Industrial strength software
Student programs for a problem & industrial
strength software are two different things
• Key difference is in quality (including usability,
reliability, portability, etc.)
– High quality requires heavy testing, which consumes 30-
50% of total development effort
– Requires development be broken in stages such that
bugs can be detected in each
– Good UI, backup, fault-tolerance, following of stds etc
increase the size for the same functionality
Maintenance
Once software delivered, it enters maintenance
phase
• Why is maintenance needed for software when it
does not wear with age?
– Residual errors requiring corrective maintenance
– Upgrades and environment changes – adaptive
maintenance
• Over software life, maintenance can cost more than
the development cost of software