CHAPTER 20- INTRODUCTION TO SYSTEMS DEVELOPMENT AND SYSTEMS ANALYSIS 1. Five Phases of the Systems Development Life Cycle (SDLC)
Systems analysis- tahap ketika seluruh informasi yang dibutuhkan untuk membeli, mengembangkan atau memodifikasi sistem dikumpulkan. Karena terbatasnya sumber daya yang dimiliki, permintaan pengembangan harus disaring dan diprioritaskan. Jika tujuannya adalah untuk membuat sistem lebih baik, maka: o (initial investigation) sifat dan ruang lingkup proyek yang diajukan harus diidentifikasi o (systems survey) lakukan survey terhadap sistem yang ada saat ini untuk mengidentifikasi o o
o
yang dibutuhkan untuk memilih atau mengembangkan sistem yang baru (deliver system requirement) Siapkan laporan system analysis dan laporkan kepada information system
steering committee Conceptual design – menentukan bagaimana memenuhi keinginan users. o (design alternatives) pilih antara membeli software, develop-in-house, outsource o (design specifications) sistem seperti apa yang ingin dibuat dan bagaimana pengendalian atas o
keunggulan dan kelemahan sistem (feasibility study) tentukan apakah proyek tersebut feasible (information needs and system requirements) jika proyek feasible, identifikasi dan dokumentasikan seluruh informasi
sistem tersebut (conceptual design requirements) permintaan desain secara konseptual dilaporkan pada information system
steering committee Physical design o mengartikan permintaan desain konseptual lebih spesifik seperti detail sandi dan uji program komputer, pembuatan dokumen input dan output, pembuatan file dan databases, pembuatan prosedur dan pengendalian o
atas sistem yang baru. (developed system) Hasil physical design kemudian dilaporkan kepada information system
steering committee Implementation and conversion – penggabungan seluruh sistem dan aktivitas pembangunan sistem
o o o o o o
perencanaan dibuat dan dilaksanakan (planning), hardware dan software diinstal dan diuji pegawai direkrut, detraining atau direlokasi prosedur diuji dan dimodifikasi standar dan pengendalian telah terbentuk dan dokumen sudah siap organisasi menggunakan sistem baru, membuat beberapa penyesuaian,
o
dan melakukan evaluasid an koreksi atas implementasi sistem baru. membuat laporan operational system dan melaporkannya kepada
information system steering committee operations and maintenance – sistem bar uterus direview dan dimodifikasi. Jika terjadi modifikasi besar-besaran atau perubahan sistem dalam tahap ini, maka proses akan kembali ke tahap pertama
2. People involved in systems development and the role they played
Management - menekan pentingnya keterlibatan
users dalam proses
pembuatan sistem, mendukung dan mendorong proyek pengembangan sistem, menyelaraskan sostem dengan tujuan perusahaan, menetapkan tujuan pembangunan sistem, memilih dan melakukan penilaian atas kinerja dari pimpinan system department, menetapkan kebijakan atas proyek yang terpilih, dan berpartisipasi dalam kepuntusan penting terkait sistem tersebut. User management menentukan informasi yang dibutuhkan, mendampingi analis dengan pertimbangan cost dan benefit, menempatkan staf dalam proyek pengembangan tersebut, dan mengalokasikan dana untuk proyek
terkait. Accountants and other users o sebagai pengguna : menentukan informasi yang dibutuhkan o sebagai anggota tim proyek atau anggota steering committee o
membantu pengembangan sistem jika diminta, akuntan dapat membantu membuat, menguji dan mengaudit
kontrol yang memastikan keakuratan dan kelengkapan pemrosesan data information system steering committee – membuat perencanaan dan mengawasi memastikan
:
information keterlibatan,
system arahan
function, dan
membuat
kontrol
dari
kebijakan
AIS,
top-management
memfasilitasi koordinasi dan integrasi aktivitas dalam sistem. Project development team – mengarahkan pengembangan, merencanakan proyek, mengawasi untuk memastikan ketepatan waktu dan efektifitas biaya penyelesaian, memastikan pertimbangan yang tepat dalam pemilihan
personel, mengkomunikasikan status proyek ke top management dan steering committee dan memfasilitasi penerimaan pengguna atas sistem
baru. System analyst and programmers o system analysts: mempelajari sistem yang ada, mendesain sistem baru, mempersiapkan detail yang dibutuhkan programmer, menjembatani gap antara manusia dan teknologi dengan sering berinteraksi dengan pegawai terkait pengembangan sistem, dan memastikan bahwa sistem yang baru o
dapat memenuhi kebutuhan users. computer programmer: membuat program berdasarkan detail yang diberikan sistem analyst dan memodifikasi atau menjaga program yang
masih ada. External players – pelanggan, vendor, auditor eksternal, dan pemerintah.
3. The importance of system developments planning and planning techniques Kenapa harus ada planning?
memudahkan untuk menyelaraskan tujuan pembuatan atau pembangunan
sistem dengan tujuan perusahaan secara keseluruhan sistem lebih efisisen, subsistem saling terhubung, dan terdapat dasar untuk
memilih aplikasi baru dalam pengembangan sistem perusahaan update dengan perubahan terbaru dalam IT sistem menjadi less costly dan lebih mudah digunakan manajemen siap untuk sumber daya yang dibutuhkan dan pegawai siap atas perubahan yang terjadi.
Bentuk planning:
Project development plan – disiapkan oleh tim proyek; berisikan analisis cost/benefit, permintaan developmental dan operasional (orang, dana, hardware,
software),
dan
jadwal
aktivitas
untuk
membangun
dan
mengoperasikan sistem yang baru. Master plan – dibuat oleh steering committee, menspesifikasikan apa saja yang
terdapat
dalam
sistem,
cara
pengembangan,
siapa
yang
mengembangkan, bagaimana mendapatkan sumber daya yang dibutuhkan, dan tujuan AIS tersebut. Teknik Perencanaan:
Program Evaluation and Review Techniques (PERT) seluruh aktivitas dan hubungan antara aktivitas sebulum dan sesudahnya harus diidentifikasi untuk menggambarka PERT diagram yang menunjukan mana aktivitas yang memerlukan pengeluaran sumber daya dan waktu yang paling banyak, penyelesaian dan awal mula suatu proyek. Setelah waktu penyelesaian
ditentukan,
tentukan
pula
critical
path
(proses
yang
memerlukan waktu pengerjaan paling lama). Gantt charts diagram batang yang terdiri dari aktivitas di bagian kiri dan satuan waktu pada bagian atas. Diagram batang digambarkan sepanjang waktu pengerjaan (starting-ending). berdasarkan
Diagram
tingkat
batang
diiisi
penyelesaiannya.
sepanjang
pengerjaan
Keuntungannya
:
proyek
diagram
ini
memperlihatkan keseluruhan progress aktivitas. Kelemahannya : diagram ini tidak dapat menunjukan hubungan antar aktivitas 4. Various types of feasibility analysis and calculate economic feasibility Kenapa
harus
nalisis
feasibility?
untuk
menentukan
menghentikan
proyek,
melanjutkan proyek tanpa syarat apapun atau melanjutkan proyek jika suatu masalah telah terselesaikan. Makin lama proyek berjalan makin sulit untuk dibatalkan, sehingga keputusan ini harus ditetapkan sedini mungkin. Jenis feasibility analysis:
economic feasibility – berapa waktu, uang dan sumber daya yang dibutuhkan untuk implementasi sitem (bandingkan biaya dengan payback period, NPV
dan IRR) technical
dikembangkan
dan
diimplementasikan dengan teknologi yang ada saat ini legal feasibility – apakah sistem telah mengikuti aturan yang berlaku scheduling feasibility – apakah sistem dapat dikembangkan
dan
diimplementasikan dalam waktu yang telah ditetapkan operational feasibility – apakah organisasi memiliki akses terhadap orang
feasibility
–
apakah
sistem
dapat
yang mendesain, mengimplementasikan dan mengoperasikan sistem ini? apakah sistem ini akan digunakan? 5. Why systems changes behavioral reactions, form of resistance and how to minimize the problem
Mengapa terjadi?
Fear-
kehilangan status, kegagalan, teknologi, dan ketidakpastian top management support- ketika kurang dukungan top mmanagemenmt ats
muncul
mdar
ketidak
tahuan,
ketakutan
kehilangan
pekerjaan,
perubahan yang dilakukan, mereka akan memopertanyakan mengapa
mereka harus menyetujui perubahan tersebut experience with prior change – ketika mereka pernah memiliki pengalam
buruk pada perubahan sebelumnya communication-pegawai tidak mau mendukung perubahan kecuali ada
penjelasan mengapa perubahan tersebut terjadi disruptive nature of change – permintaan informasi dan interview membuat mereka
menggangu
dan
menambah
beban
bagi
pegwai
sehingga
menimbulkan kesan negatif manner in which chang is occurred – alasn perubahan yang diterma top
management bisa jadi tidak dpt diterima oleh lower level biases and emotions – jika sisi emosional terpengaruh personal characteristic and background – semakin muda dan semakin berpendidikan lebih mudah menerima perubahan
Bentuk penolakan:
aggression perilaku yang merusak, melumpuhkan dan melemahkan sistem, seperti meningkatnya kesalahan atau sabotase. projection menyalahkan sistem jika suatu hal berjalan tidak sesuai. avoidance mengacuhkan sistem yang baru dengan harapan sistem tersebut tidak akan digunakan lagi.
Bagaimanan mencegah hal tersebut terjadi? dapatkan dukungan manajer, penuhi kebutuhan users, libatkan users dalam proses pembuatan, menekankan keuntungan sistem baru, bersikap loggis, megadakan training, evaluasi kinerja sistem baru, selalu membuka komunikasi dengan users, menguji sistem, dan humanize sistem. CHAPTER 21 – AIS DEVELOPMENT STRATEGIES
Purchasing software canned software-djual pada pengguna yang memiliki kesamaan kebutuhan, turnkey software-software yang dijual sepaket dengan hardware nya. ASP merupakan pnyedia jasa penyewaan software mellaui internet. Tahap :
pemilihan vendor-bisa mellaui konferensi, internet, majalah, buku telepon, dll. acquiring hardware-software – untuk pembelian yang banyak dan complex maka gunakan RFP agar: menghemat waktu )tanpa harus interview berulang), menyederhanakan proses pembuatan keputusan (semua respons berdasarkan format dan info yang sama), mengurangi eror (tidak perlu overlook), dan mengurangi kemungkinan ketidakcocokan (masing2 pihak sudah memiliki ekspektasi tertentu). Kekurangannya : vendor tidak dapat menyarankan alternatif lain, masalah teknis yang menjadi urusan vendor sulit
dianalisa dan mnambah biaya yang dikenakan. evaluating proposal and select system – proposal yang menyediakan informasi yang kurang, tidak memenui permintaan dasar dan ambigu akan ditolak. Jika lolos dalam paper screening, proposal dicocokan dengan sistem requirement. vendor kemudian diminta untuk mendemonstrasikan sisrem tersebut. Membandingkan vendor dengan menggunakan point scoringdimana tiap-tiap kriteria diberikan berat brebeda berdasarkan tingkat kepentingannya.
Setelah
itu
membandingkan
biaya
yang
dibutuhkan
(purchasing cost + requirement cost).. Development in house End user developed software end user computing – pengembangan, penggunaan dan pengendalian sistem dilakukan oleh users Keuntungan:
user creation, control and implementation-user mengendalika proses
pengembangan system that meet user needs
timeliness- menghemat waktu freeing up of system resources – sumberdaya dapat digunakan untuk
pengembangan sistem lain versatility and ease of use – mudah dipahami, dapat dimodifikasi, dan dpat digunakan diamana saja
Kelemahan :
logic and development error- user yang mengembangkan sistem tidak memiliki pengetahuan IS yang baik, sehingga seringkali mereka banyak
melakukan eror atau tidak menyadari adanya eror tersebut inadequately tested application – jarang dilakukan tes yang menyeluruh
karene tidak mengetahui kegunaan tes tersebut inefficien systems poorly controlled and documented system: system incompatibilities wasted resources – ada duplikasi sistem increased cost- update
Cara mengatasi kelemahan : help desk (menyelesaikan masalah, evaluasi hardware software baru, melakukan training, menyediakan bantuan teknis dan pendampingan dalam pembuatan aplikasi OUTSOURCING Merupakan kegiatan merekrut perusahaan luar untuk menangani seluruh aktivitas pemrosesan data organisasi. Keuntungan:
a business solution –agar perusahaan lebih fokus pada bisnis utamanya asset utilization – menjual aset pada outsourcer access to greater expertise and better technology – diserahkan pada ahlinya lower cost – mengurangi biaya labor, instalasi, dll less development time – perusahaan outsourcer yang baik dapat
mengerjakan pengembangan lebih cepat elimination of peaks and valley usage – mengurangi penggunanaan untuk
mengurangi operational cost facilitation of downsizing – merampingkan struktur
Kelemahan :
inflexibility – kontrak berkisar 10 tahun, jika ada ketidak[uasan dari pelnggan
sangat sulit proses untuk pembatalan kontrak tersebut loss of control –terutama kontrol atas system dan data reduce competitive advantage – karena tidak mengetahui proses locked in system – pengeluaran cukup besar, sehingga harus tetap
menggunakan sistem yang dibangun unfulfilled goals – banyak tujuan yang tidak terpenuhi poor service – outsourcer kurang responsive terdapat perubahan yang terjadi increased risk – ope, fin, tech, strategy , personnel, legal dan regulatory risk
BUSINESS PROCESS MANAGEMENT Business process reengineering (BPR) is the analysis and redesign of business processes
and
information
systems
to
achieve
significant
performance
improvements. Karena dinilai kurang efektif maka proses ini dikembangkan menjadi BPM dengan pengembangan yang m=berkelanjutan untuk mengoptimalkan proses bisnis dalam organisasi. Prinsip penting di bawah BPM :
Proses bisnis dapat menciptakan competitive advantage Proses bisnis harus dikoordinasikan dan dikomunikasikan dengan baik. business proses harus dapat beradaptasi mennyesuaikan perubahan yang
terjadi bisnis proses harus selaras dengan tujuan dan kebutuhan perusahaan
empat komponen utama BPM :
proses untuk membuat dan menjalankan aplikasi, termasuk peraturan dalam
bisnis analisa bisnis untuk mengidentifikasi isu, tren dan kesempatan integrasi seluruh aktivitas menyetorkan dan mengamankan dokumen dan file penting lainnya
PROTOTYPING Four steps are involved in developing a prototype: 1. STEP ONE: Identify basic requirements The first step is to identify basic requirements by meeting with users to agree on the size and scope of the system and decide what it should include and exclude. Developer and users also determine decision-making and transaction processing
outputs and inputs and data needed to produce those outputs. The emphasis is on what outputs should be produced rather than how. The developer must ensure user expectations are realistic and their basic information requirements are met. The designer uses the information requirements to develop cost, time, and feasibility estimates for alternative AIS solutions 2. STEP TWO: Develop an initial prototype The second step involves developing an initial prototype that meets the agreed-on requirements. The emphasis is on speed and low cost rather than efficiency of operation. The goal is to implement the prototype within a short time period. Because of time constraints, some aspects are sacrificed. For example, at this point, there is ignorance of non-essential functions, system controls, exception handling, validation of input data, processing speed, and efficiency considerations. Users must see and use tentative versions of data entry display screens, menus, input prompts, and source documents. They must also respond to prompts, query the system, judge response times, and issue commands. When the prototype is finished, the developer returns to the users and demonstrates the system. Users are instructed to experiment and comment on what they do and do not like. 3. STEP THREE: Repeated iterations The third step involves repeated iterations of users identifying changes, developers making the changes, and the system being turned back to users for next round. This step continues until users are satisfied—usually 4 to 6 iterations. 4. STEP FOUR: Use the system The final step involves using the system approved by the users. An approved prototype is typically used in one of two ways. Half of the prototypes are turned into fully functional systems referred to as operational prototypes. To make them operational, the developer must add needed controls, improve operational efficiency, provide backup and recovery, and integrate the prototype with the systems with which it interfaces. Changes may be necessary to allow the program to accept real input, access real data files, process data, make necessary computations and calculations, and produce real output. When it’s not practical to
modify the prototype to make a fully functional system, non-operational or throwaway prototypes can be used in several ways. They may be discarded, and the systems requirements identified in the process of building them can be used to develop a new system. If so, the SDLC is followed to develop the system, and the prototype is a model. Alternately, they may be used as the initial prototype for an expanded system designed to meet needs of many users. As a final alternative, if users and developers decide the system is unsalvageable, the prototype can be discarded completely. There are some advantages of prototyping : 1. Better definition of user needs -- Because of intensive end-user involvement 2. Higher user involvement and satisfaction 3. Faster development time -- It may take days or weeks to get a prototype up vs. a year or more for a traditional system 4. Fewer errors -- Errors are detected early because the users experiment with each version. It’s also easy to identify and terminate an infeasible AIS early 5. More opportunity for changes 6. Less costly -- Some for 10–20% of the cost of traditional systems Despite its advantage, prototype also has several disadvantages : 1. Significant user time 2. Less efficient use of system resources -- Shortcuts in developing the system may result in poor performance and reliability and high maintenance and support costs 3. Incomplete system development 4. Inadequately tested and documented systems
5. Negative behavioral reactions -- If the prototype is discarded, users may be upset about using it and losing it. Users may also be dissatisfied if all their suggestions are not incorporated or if they have to go through too many iterations 6. Never-ending development -- If not managed properly, the development could get stuck in a terminal loop CASE TOOLS Computer-aided software (or systems) engineering (CASE) tools are an integrated package of computer-based tools that automate important aspects of the software development process. It is used to plan, analyze, design, program, and maintain an information system. It is also used to enhance efforts of managers, users, and programmers in understanding information needs. There are several advantages of CASE technology : 1. Increased
productivity
--
Can
generate
bug-free
code
from
system
specifications and automate repetitive tasks 2. Improved program quality -- Can simplify enforcement of structured development standards, which improves quality of development and reduces threat of serious design errors; can check internal accuracy of design and detect inconsistencies 3. Cost savings -- Cost savings of up to 80–90% are possible 4. Improved control procedures -- Encourages development early in the design process of system controls, security measures, system auditability, and error handling procedures 5. Simplified
documentation
--
Automatically
documents
as
the
system
development progresses Despite its advantage, CASE technology also has several disadvantages : 1. Incompatibility -- Some tools don’t interact effectively with some systems
2. Cost -- Some packages > $360,000 3. Unmet expectations -- Only 37% of CIOs believe they achieved expected benefits CHAPTER 22 – SYSTEM DESIGN, IMPLEMENTATION AND OPERATION Conceptual Systems Design In the conceptual systems design phase, a general framework is created for implementing user requirements and solving the problems identified in the analysis phase. The three main steps are : 1. Evaluate design alternatives The steering committee evaluates the alternatives. Following are some design considerations and alternatives:
How should the communications channel be configured? -- Point-to-point, Multi-drop, or Line-sharing
What type of communications channel should be used? -- Phone lines, Coaxial cable, Fiber optics, Microwave, or Satellite
What type of communications network should be used? – Centralized, Decentralized, Distributed, or Local area
What type of storage media should be used for data? – Tape, Disk, Diskette, Hard drive, CD, or Paper
What type of data storage structure should be used? – Files or Database
How should files be organized and accessed? – Random, Sequential, orIndexed-sequential access
What media should be used to input data? – Keying, OCR, MICR, POS, EDI, or Voice
What format will the input take? -- Source documents, Turnaround documents, Source data automation, or Screen
How will the system be operated? -- In-house or Outsourcing How frequently will outputs be produced? – Instantly, Hourly, Daily, Weekly, or Monthly
What media will be used for output? – Paper, Screen, Voice, Diskette, CD, or Microfilm
How will output be scheduled? -- On demand or at predetermined times
What format will the output take? – Narrative, Table, Graph, Electronic file or communication
What form will printed output take? -- Pre-printed forms, Turnaround documents, or System-generated forms
What processing mode will be used? – Manual, Batch, orReal time
What
type
of
processor
will
be
utilized?
--
Personal
computer,
Minicomputer, or Mainframe
How will software be acquired? – Canned, Custom, or Modified
How will transactions be processed? -- By batch or Online
How frequently will updates occur? – Instantly, Hourly, Daily, Weekly, or Monthly
2. Prepare design specifications Once a design has been selected, the project team develops the conceptual design specifications for the following elements:
Output -- Because output is what goes to the user and the system must be designed to meet user needs, the output specifications are prepared first
Data storage -- How will data be stored to produce the desired outputs?
Input -- What types of data must be entered to produce the desired outputs?
Processing procedures and operations -- How will data be processed and in what sequence to produce the desired outputs?
3. Prepare the conceptual systems design report. A conceptual systems design report is prepared at the end of the conceptual design phase to guide physical system design activities, communicate how management and user information needs will be met, and help the steering committee assess system feasibility. Physical System Design 1. Output Design The objective of output design is to determine the nature, format, content, and timing of printed reports, documents, and screen displays. Important design considerations include :
Use of the output -- Who will use it and why?, when is it needed?, and what decisions will it facilitate?
Output medium – Paper, Screen, Voice response, Diskette, Microfilm, and Other
Output format -- Should select the format that clearly conveys the most information. It could be table, narrative, or graphic.
Pre-printed -- Should paper output be on preprinted form and/or turnaround document?
Location -- Where is the output to be sent?
Access -- Who should be able to access hard-copy and screen output?
Detail -- Lengthy output should be preceded by an executive summary and a table of contents. Headings and legends organize data and highlight important items. Detailed info goes in an appendix.
Timeliness -- How often should the output be produced?
Outputs usually fit into one of the following four categories:
Scheduled reports -- have pre-specified content and format, are prepared on a regular basis, for examples: weekly sales analysis and monthly financial statements
Special-purpose analysis reports -- no pre-specified content and format, typically prepared in response to a management request, for example: analysis of impact of a government mandate on profitability
Triggered exception reports -- have pre-specified content and format, prepared only in response to abnormal conditions, i.e., the “trigger”, for example: cost overruns
Demand reports -- have pre-specified content and format and prepared only on request.
2. File and database design Important file and database design considerations include:
Storage medium -- Hard drive, Disk, Diskette, CD, Tape, or Paper
Processing mode – Manual, batch or real time
Maintenance -- What procedures are needed to effectively maintain the data?
Size -- How many records and how big are they? and how fast are they expected to grow?
Activity level -- What portion of records are added or deleted each year? and what portion needs to be updated?
3. Input design There are two principal types of data input,
forms and computer screens.
Considerations in input design include:
Input medium – Keyboard, OCR, MICR, POS terminal, EDI, and Voice input
Input source – Computer, Customer, and Remote location
Input format -- Source or turnaround document, screen, and source data automation
Input type -- What is the nature of the data?
Volume -- How much data are to be entered?
Personnel -- What functions and expertise do the data entry operators have? and is additional training necessary?
Frequency -- How often is data to be entered?
Cost -- How can costs be minimized without adversely affecting efficiency and accuracy?
Error detection and correction -- What errors are possible? and how can they be detected and corrected?
4. Form design Following are important principles for designing new forms and evaluating existing ones: •
General considerations -- Preprint as much data as possible; use appropriate weight and grade of paper; use bold type, double-thick lines, and shading to highlight different parts of the form; use a standard size and one that is consistent with requirements for filing, binding, or mailing; if mailed to external parties, position the address for placement in a window envelope;
have copies of the form printed in different colors to facilitate accurate distribution; and include clear instructions for completing the form. Introductory section of form -- Place the form name at the top in
•
bold type; have the forms pre-numbered consecutively; and if distributed to external parties, have company name and address pre-printed on the form. Main body of form -- Group together logically related information
•
(e.g., info about the customer, info about the product); provide sufficient room to record each item; order the data items consistent with the sequence in which the data is likely to be gathered; use codes and check-offs in places where standardized explanations are likely. Conclusion section of form -- Provide space for recording final
•
disposition of the form, approval signatures, dates of approval and final disposition, and a dollar or numeric total ; clearly indicate the distribution of each form. Computer screens are most effective when the following principles are used:
Organize the screen for quick, accurate, and complete entry of the data -Minimize input by retrieving as much as possible from the system. Example: If the customer number is entered, retrieve his name/address data from the system.
Enter data in the same order it appears on the document
Complete the screen from left to right and top to bottom, grouping logically related data together
Design the screen so users can jump from one data entry location to another or use a single key to go directly to screen locations
Make it easy to correct mistakes -- Use clear and explicit error messages that are consistent on all screens and provide a help feature for online assistance
Avoid clutter by restricting the amount of data on one screen -- Limit the number of menu options on a single screen
5. Program design The following slides discuss the eight steps for developing software and where these steps take place in the SDLC.
STEP ONE: Determine user needs -- Occurs during the systems analysis stage of the SDLC.
STEP TWO: Develop and document a plan -- Occurs during the conceptual design phase and the beginning of physical design.
STEP THREE: Write the program code -- Design in increasing levels of detail, known as hierarchical program design. It begun during systems design and completed during systems implementation.
STEP FOUR: Test the program code -- Debugging is discovering and eliminating program errors. Desk checking happens after a program is coded and involves a visual and mental review to discover programming errors. Programs are tested for logic errors using test data that simulates both valid transactions and all possible error conditions. Large programs are often tested in three stages, such as individual program modules, the linkages between the module and the control module, and the interfaces between the program being tested and other application programs. Errors need to be found as soon as possible in the development process. Errors discovered late cost 80–1000% more to fix than those found early.
STEP FIVE: Document the program -- Documentation explains how programs work and helps correct and resolve errors. It includes flowcharts, record layouts, E-R diagrams, REA data models, narrative descriptions of the system, etc., organized in a manual.
STEP SIX: Train program users -- Often uses the program documentation.
STEP SEVEN: Install the system -- All components are brought together, and the company begins to use the system.
STEP EIGHT: Use and modify the system -- Program maintenance is a response to any factors that require program revision. It includes requests for new or revised reports; changes in input, file content, or values such as tax rates; error detection and correction; and conversion to new hardware.
6. Procedure design Individuals who interact with a newly-designed AIS need procedures to cover input preparation, transaction processing, error detection and correction, controls, reconciliation of balances, database access, output preparation and distribution, and computer operator instructions. Procedures may take the form of system manuals, user instruction classes, training materials, and online help screen. The procedures may be written by development teams; users; or teams representing both groups. 7. Controls design Improperly
controlled
input,
processing,
and
database
functions
produce
information of questionable value. Controls must be built into an AIS to ensure its effectiveness, efficiency, and accuracy. These controls should minimize errors and detect and correct errors when they do occur. Accountants play a vital role in this area. Important control concerns that must be addressed include:
Validity -- Are all interactions valid?
Authorization -- Are input, processing, storage, and output activities authorized by the appropriate managers?
Accuracy -- Is input verified to ensure accuracy? and what controls ensure that data is not lost when passing between processing activities?
Security -- Is the system protected against unauthorized physical and logical access to prevent improper use, alteration, destruction, or disclosure of information and software and theft of system resources?
Numerical control -- Are documents pre-numbered to prevent errors or intentional misuse and to detect when documents are missing or stolen?
Availability -- Is the system available as set forth in agreements? and can users enter, update, and retrieve data during those times?
Maintainability -- Can the system be modified without affecting system availability, security, and integrity?; Are only authorized, tested, and documented changes made to the system and data?; Are resources available to manage, schedule, document, and communicate changes to management and authorized users?
Integrity
--
Is
processing
authorized?;
Is
it
free
complete, from
accurate,
unauthorized
or
timely,
and
inadvertent
manipulations?
Audit trail -- Can data be traced from source to output and vice versa?
8. Physical system design report At the end of the physical design phase, a physical systems design report is prepared, summarizing what was accomplished. This report serves as the basis for management’s decision whether to proceed to implementation. Systems Implementation and Conversion Systems implementation is the process of installing hardware and software and getting the AIS up and running. Phases include 1. Developing a plan An implementation plan consists of implementation tasks, expected completion dates, cost estimates and specification of the person(s) responsible for each task. The plan specifies when the project should be complete and operational. The implementation team should identify risk factors that decrease the likelihood of successful implementation, and the plan should contain a strategy for coping with
each of the risks. AIS changes may require adjustments to the company’s organizational structure, including creation of new departments; elimination or downsizing of existing departments; and changes even in the data processing department. 2. Preparing the site : Installing and testing hardware and software A large computer may require changes such as new electrical outlets; data communications facilities; raised floors; humidity controls; special lighting; airconditioning; security measures, such as fire protection and emergency power supply; space for equipment, storage, and offices. Site preparation is a lengthy process and should begin well ahead of the installation date. 3. Selecting and training personnel Employees can be hired from outside or transferred internally. Hiring from within is usually more effective and less costly, because the employees already understand the business. Transferring displaced employees can enhance loyalty and morale. Companies take training shortcuts because effective training is time-consuming and expensive and those who understand the system are maintaining and upgrading it. When training is insufficient, the company will not achieve the expected return on investment. The hidden cost is that users will turn to their coworkers who have mastered the system for help. It results in less productive coworkers and increased costs. Effective training includes hardware and software skills and orientation to new policies and operations. The training should be scheduled just before systems testing and conversion. Types of training include technical training from vendors, self-study manuals, computer-aided instruction, videotape presentations, roleplaying, case studies, and experimenting with the AIS under the guidance of experienced users. 4. Completing documentation Three types of documentation must be prepared for new systems:
Development documentation -- Describes the AIS and includes a system description;
copies of output, input, file, and database
layouts; program flowcharts; test results; and user acceptance forms.
Operations documentation – Includes operating schedules; files and databases accessed; and equipment, security, and file retention requirements
User documentation -- Teaches users how to operate the AIS. and includes a procedures manual and training materials. 5. Testing the system
Inadequate system testing has contributed to the failure of systems. Three common forms of testing include:
Walk-throughs -- Step-by-step reviews of procedures or program logic : Attended by the development team and users early in system design; focus is on organization input, files, outputs, and data
flows;
subsequent
walk-throughs
are
attended
by
programmers; and address logical and structural aspects of program code.
Processing test transactions -- Determines whether the program operates as designed; requires both valid and erroneous data; the correct response for each test should be specified in advance.
Acceptance tests -- Uses copies of real transactions and files rather than hypothetical ones; users develop acceptance criteria; and then make final decision whether to accept.
Conversion is the process of changing from the old AIS to the new. Many elements must be converted, including hardware, software, data files, and procedures. The process is complete when the new AIS has become a routine, ongoing part of the system. Four conversion approaches are used to change from an old to a new system: 1. Direct conversion
Immediately terminates the old AIS when the new one is introduced. Appropriate when the old AIS has no value; or the new AIS is so different that comparisons between the two are meaningless. Main advantage to direct conversion is inexpensive, but the main disadvantage is it provides no backup AIS. There is a high risk of failure unless the new system has been very carefully developed and tested. 2. Parallel conversion Operates the old and new systems simultaneously for a period of time. You can process transactions with both systems, compare output, reconcile differences, and make corrections to the new AIS. Main advantage to parallel conversion is it protects the company from errors but the main disadvantage is it is costly and stressful for employees to process all transactions twice. Because companies often experience problems during conversion, parallel processing has gained widespread popularity. 3. Phase-in conversion Gradually replaces elements of the old AIS with the new one. The new system is often phased in a module at a time. The main advantage is data processing resources can be acquired over time, but the disadvantages are costs of creating temporary interfaces between old and new AIS and time required to make the complete conversion. 4. Pilot conversion Implements a system in just one part of the organization, e.g., a branch office or a single store. When problems with the system are resolved, the new system could be implemented at the remaining locations. The advantages of this conversion is it localizes conversion problems and allows training in a live environment. But the disadvantages are long conversion time and need for interfaces between old and new systems. Data conversion can be time-consuming, tedious, and expense. The difficulty and magnitude is easy to underestimate. Data files may need to be modified in three ways, there are files may be moved to a different storage medium (e.g., tape to
disk), data content may be changed (e.g., fields added or deleted), and a file or database format may be changed. Steps in the data conversion process: 1. Decide which data files need to be converted. 2. Check files for completeness and data inaccuracies, and remove any inconsistencies. 3. Do the actual data conversion.
