3. SOFTWARE DEVELOPMENT STEPS
System Design
ANALYST
DESIGNER
PROGRAMMER
Program Design
Program Implementation
TESTER
Unit Testing
Integration Testing
System Testing
TRAINER
System Delivery
Maintenance
Figure1.11 The roles of the development team
DEVELOPER ROLES
Requirements Analysis
and Definition
4. Object technology
Desktop computing
Problems with waterfall
CHANGES IN
SOFTWARE
ENGINEERING
Time to market
Networking
Shifts in economics
User interfaces
Figure1.12 The key factors that have changed software development
16. VARIETY OF SOFTWARE PRODUCTS
Real time
Embedded systems
Data processing
pensions
Information systems
libraries
Sensors
System software
compilers
Communications
telephones
Offices
conferences
Scientific
forecasting
Graphical
: air traffic control
: digital camera, GPS
: telephone billing,
: web sites, digital
: weather data
: operating systems,
: routers, mobile
: word processing, video
: simulations, weather
: film making, design
18. WHAT IS SOFTWARE ENGINEERING?
Software engineering is an
engineering discipline that is
concerned with all aspects of software
production.
19. WHAT IS SOFTWARE ENGINEERING?
Software engineers should adopt a
systematic and organised approach
to their work and use appropriate tools and
techniques depending on the problem to
be solved, the development constraints and the
resources available.
21. SOFTWARE ENGINEERING VS COMPUTER
SCIENCE?
Computer Science
Software Engineering
Computer science is
concerned with theory and
fundamentals;
Computer science theories
are still insufficient to act as
a complete underpinning for
software engineering (unlike
e.g. physics and electrical
engineering).
Software engineering is
concerned with the
practicalities of developing
and delivering useful
software.
22. SOFTWARE ENGINEERING VS SYSTEM
ENGINEERING?
System engineering
Concerned with all aspects
of computer-based systems
development including
hardware, software and
process engineering.
System engineers are
involved in system
specification, architectural
design, integration and
deployment.
Software engineering
concerned with developing
the software infrastructure,
control, applications and
databases in the system.
23. WHAT IS A SOFTWARE PROCESS?
A set of activities whose goal is the
development or evolution of
software.
30. SOFTWARE COSTS
Software costs often dominate computer system costs. The
costs of software on a PC are often greater than the hardware
cost.
Software costs more to maintain than it does to develop. For
systems with a long life, maintenance costs may be several times
development costs.
Software engineering is concerned with cost-effective software
development.
31. WHAT ARE THE COSTS OF SOFTWARE
ENGINEERING?
Roughly 60% of costs are development costs, 40% are testing
costs. For custom software, evolution costs often exceed
development costs.
Costs vary depending on the type of system being developed
and the requirements of system attributes such as performance
and system reliability.
Distribution of costs depends on the development model that
is used.
32. WHAT IS CASE (COMPUTERAIDED SOFTWARE ENGINEERING)
Software systems that are intended to provide automated
support for software process activities.
CASE systems are often used for method support.
Upper-CASE
Tools to support the early process activities of requirements and
design;
Lower-CASE
Tools to support later activities such as programming, debugging and
testing.
34. WHAT ARE THE ATTRIBUTES OF GOOD
SOFTWARE?
The software should deliver the required
functionality and performance to the user and should
be maintainable, dependable and acceptable.
Maintainability
◦
Dependability
◦
Software must be trustworthy;
Efficiency
◦
Software must evolve to meet changing needs;
Software should not make wasteful use of system
resources;
Acceptability
◦
Software must accepted by the users for which it was
designed. This means it must be understandable, usable
and compatible with other systems.
35. WHAT ARE THE KEY
CHALLENGES FACING SOFTWARE
ENGINEERING?
Heterogeneity, delivery and trust.
Heterogeneity
◦
Delivery
◦
Developing techniques for building software that can cope with
heterogeneous platforms and execution environments;
Developing techniques that lead to faster delivery of software;
Trust
◦
Developing techniques that demonstrate that software can be trusted
by its users.
36. KEY POINTS
Software
engineering is an engineering discipline that
is concerned with all aspects of software production.
Software products consist of developed programs and
associated documentation. Essential product attributes
are maintainability, dependability, efficiency and
usability.
37. CONTINUE..
•
•
The software process consists of activities that are involved in
developing software products. Basic activities are software
specification, development, validation and evolution.
Methods are organised ways of producing software. They
include suggestions for the process to be followed, the
notations to be used, rules governing the system descriptions
which are produced and design guidelines.
