Rekayasa Perangkat Lunak

Kuliah 2

Outline of this presentation

• Attributes of Good Software• Why Software Engineering ?• What is Software Product ?• Software Myths

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Attributes of Good Software

• Maintainability

• Dependability

• Efficiency

• Usability

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Attributes of Good Software

• Maintainability •more than 50% of software cost is due to

maintenance• Easy to maintain– Good Documentation– Good Design

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Attributes of Good Software

• Dependability • Reliability, – Do the Right Process

• Security,– Good Thread Protection

• Safety– No Surprise– On-line & Off-line Help

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Attributes of Good Software

• Efficiency • Memory,– Small Memory Usage

• CPU time– Efficient cycle time

• Storage– Minimum Amount of Storage

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Attributes of Good Software

• Usability • User Interface– Familiar Look– Nice & Complete– Incorporate Message Alert

• Documentation– User Guide» Thorough & Complete

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Why Software Engineering ?

• Analogy with bridge building:

–Over a stream • easy, one person job

–Over River Severn … ? • (the techniques do not scale)

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Why Software Engineering ?

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...to get away from ad hoc and unpredictable software development towards a systematic, understood one…

What is Software Product ?

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a general market

Software products may be developed for :

or may be developed for a particular customer

What is Software Product ?

• Software products may be– Generic (for general market)

developed to be sold to a range of different customers e.g. Excel or

Word or Visual Basic etc

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What is Software Product ?

• Software products may be– Bespoke / Custom (for particular customer)

developed for a single customer according to their specification.e.g. ………..

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• New software can be created by –Developing new programs,

or–Reusing existing software

or–Configuring generic software systems

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• New software can be created by –Developing new programs, • Starting from scratch• one full development cycle

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• New software can be created by –Reusing existing software• Not starting from scratch• Using own working software •Modifying & Adapting with the New

Requirement

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• New software can be created by –Configuring generic software systems• Not starting from scratch• Using on the shelve software• Tailoring with the requirement

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Software Myths

• Wrong Assumption From

– Management• Cost - Schedule - Quality

– Customer• Use

– Developer• Build

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• Management Myths• Myth– Standard and procedures are already exist for

producing software• Fact– Standards are rarely used– Developers rarely know about them– Standards are often out-of date and incomplete

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• Management Myths (cont.)• Myth– State-of-the-art tool are the solution

• Fact–A fool with a tool is still a fool

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• Management Myths (cont.)• Myth– If we get behind schedule, we can always add more

peoples and thus catch up

• Fact– Software development is not a mechanistic process

like manufacturing. – Adding people to a late software project makes it later. – What about Training - Integration - Social Aspect

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• Developer Myth• Myth– The only deliverable is the working program(s).

• Fact– A working program is only one part of a software

configuration that includes requirements and specification documents, testing information and other developmental and maintenance information.

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• Developer Myth (cont.)• Myth–Once the program is written and it works,

then the job is done. • Fact–Between 50 and 70 percent of all effort

expended on a program will be expended after it is delivered to the customer.

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• Developer Myth (cont.)• Myth–Until the program is running, there is no

way to assess its quality. • Fact–One of the most effective software quality

assurance mechanisms is the formal technical review and this can be applied from the inception of the project.

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• Customer Myth • Myth–A general statement of objectives is

sufficient to begin writing programs - we can fill in details later.

• Fact– Thorough communication between

customer and developer needed25

• Customer Myth (cont.)• Myth –Changes can be easily accommodated

because software is flexible • Fact–Changes happen as a fact of life– late changes are expensive

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