Rekayasa Perangkat Lunak (Software Engineering)
Andi Sunyoto, M.Kom Email:
[email protected] [email protected] Web: andi.amikom.ac.id
Why Software Engineering ?
FAQs about software engineering What is software? What is software engineering? What is the difference between software engineering and computer science? What is the difference between software engineering and system engineering? What is a software process? What is a software process model?
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FAQs about software engineering What are the costs of software engineering? What are software engineering methods? What is CASE (Computer-Aided Software Engineering) What are the attributes of good software? What are the key challenges facing software engineering?
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What is software? Computer programs and associated documentation such as requirements, design models and user manuals. Software products may be developed for a particular customer or may be developed for a general market. Software products may be Generic - developed to be sold to a range of different customers e.g. PC software such as Excel or Word. Bespoke (custom) - developed for a single customer according to their specification.
New software can be created by developing new programs, configuring generic software systems or reusing existing software 5
What is software engineering? Software engineering is an engineering discipline that is concerned with all aspects of software production. 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.
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What is the difference between software engineering and system engineering? System engineering is concerned with all aspects of computer-based systems development including hardware, software and process engineering. Software engineering is part of this process concerned with developing the software infrastructure, control, applications and databases in the system. System engineers are involved in system specification, architectural design, integration and deployment. 7
What is a software process? A set of activities whose goal is the development or evolution of software. Generic activities in all software processes are: Specification - what the system should do and its development constraints Development - production of the software system Validation - checking that the software is what the customer wants Evolution - changing the software in response to changing demands.
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What is a software process model? A simplified representation of a software process, presented from a specific perspective. Examples of process perspectives are Workflow perspective - sequence of activities; Data-flow perspective - information flow; Role/action perspective - who does what.
Generic process models Waterfall; Iterative development; Component-based software engineering. 9
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. 10
Activity cost distribution Waterfall model 0
25
Specification
50
Design
100
75
Development
Integ ration and testing
Iterative development 0
25
Specification
75
Iterative development
Component-based software eng 0
25
Specification
50
Sy stem testing
ineering 50
75
Development
10
Sy stem development
1 00
Integ ration and testing
Development and evolution costs for long-lifetime sy st 0
1 00
ems
200
30
400
Sy stem evolution
11
Product development costs
0
Specification
25
Development
50
75
100
Sy stem testing
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What is CASE (Computer-Aided 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.
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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 Software must evolve to meet changing needs;
Dependability Software must be trustworthy;
Efficiency 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.
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What are the key challenges facing software engineering? Heterogeneity, delivery and trust. Heterogeneity Developing techniques for building software that can cope with heterogeneous platforms and execution environments;
Delivery Developing techniques that lead to faster delivery of software;
Trust Developing techniques that demonstrate that software can be trusted by its users. 15
Software category: system software: computer software designed to operate the computer hardware and to provide and maintain a platform for running application software. The computer BIOS and device firmware. The operating system (prominent examples being Microsoft Windows, Mac OS X and Linux) Utility software, which helps to analyze, configure, optimize and maintain the computer.
application software: is a computer software designed to help the user to perform singular or multiple related specific tasks. Examples include enterprise software, accounting software, office suites, graphics software, and media players.
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Software category: engineering/scientific software: is a computational software program used in scientific, engineering, and mathematical fields and other areas of technical computing.
embedded software: is computer software which plays an integral role in the electronics it is supplied with. Embedded software is 'built in' to the electronics in cars, telephones, audio equipment, robots, appliances, toys, security systems, pacemakers, televisions and digital watches, for example. This software can become very sophisticated in applications like airplanes, missiles, process control systems, and so on.
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Software category: product-line software: tools and techniques for creating a collection of similar software systems from a shared set of software assets using a common means of production. For example, automotive manufacturers can create unique variations of one car model using a single pool of carefully designed parts and a factory specifically designed to configure and assemble those parts.
WebApps (Web applications): is an application that is accessed over a network such as the Internet or an intranet. The term may also mean a computer software application that is hosted in a browser-controlled environment (e.g. a Java applet)[citation needed] or coded in a browser-supported language (such as JavaScript, combined with a browser-rendered markup language like HTML) and reliant on a common web browser to render the application executable. 18
Software category: AI software: is the intelligence of machines and the branch of computer science that aims to create it. Sistem seperti ini umumnya dianggap komputer. Kecerdasan diciptakan dan dimasukkan ke dalam suatu mesin (komputer) agar dapat melakukan pekerjaan seperti yang dapat dilakukan manusia. Beberapa macam bidang yang menggunakan kecerdasan buatan antara lain sistem pakar, permainan komputer (games), logika fuzzy, jaringan syaraf tiruan dan robotika.
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Software Evolution First Era: Batch orientasi Distribusi terbatas Perangkat lunak Customasi
Second Era: Multiuser Real-time Database Software product
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Third Era: Sistem terdistribusi Embedded intelligent Low hardware cost
Fourth Era: High Performance Desktop System OOP Technology Expert Sistem Neural Network Paralel Computation Computer Network 21
Problem without SE ?
Tidak sesuai kebutuhan Over Budget Terlambat Error Sulit dikembangkan
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Mitos Manajemen Mitos: Saya sudah mempunyai perangkat H/w dan S/w terbaru.
Kenyataan: Tidak sekedar H/w tinggi. Ternyata untuk mencapai produktivitas tinggi diperlukan CASE (Computeraided software engineering)
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Mitos Manajemen Mitos: Jika menambah jumlah programmer dapat mengejar ketinggalan.
Kenyataan: Menambah jumlah programmer ketika proses berjalan akan semakin ketinggalan, karena dapat memperlambat pekerjaan.
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Mitos Pelanggan Mitos: Pernyataan umum obyektif sudah dapat untuk menuliskan program. Detail belakangan.
Kenyataan: Definisi awal yg buruk merupakan awal kegagalan membangun S/w. Deskripsi detail informasi, fungsi, unjuk kerja, interface, desain contraint, validasi merupakan hal yang paling mendasar.
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Mitos Pelanggan Mitos Kebutuhan proyek yang terus berubah dapat diakomodasi, karena S/w bersifat fleksibel.
Kenyataan: Perubahan dapat menyebabkan “pergolakan” dan membutuhkan sumber daya yang besar. Perubahan software biayanya jauh lebih besar dibanding perubahan di awal.
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Mitos Praktisi Mitos: Teknik Perancangan dan Analisa hanya memperlama selesainya program.
Kenyataan: Program yang dirancang dengan teliti, detail, seksama, selesai lebih cepat dengan tingkat efektifitas lebih tinggi.
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Mitos Praktisi Mitos: Kualitas program hanya dinilai ketika sudah dapat berjalan.
Kenyataan: Tinjauan perangkat sebelumnya merupakan cara efektif untuk memfilter kualitas perangkat lunak.
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Mitos Praktisi Mitos: Ketika program selesai dan jalan, maka proyek dianggap sukses.
Kenyataan: Program berjalan adalah bagian dari konfigurasi perangkat lunak yang menyangkut program, dokumen dan data. Dokumentasi merupakan fondasi untuk pengembangan yang berhasil, dan memberikan tuntunan untuk pemeliharaan.
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