as reais razões do porque eu devo ser Ágil - agile tour são paulo
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Introdução à metodotoligias ágeis,TRANSCRIPT
As reais razões do porque eu devo ser Ágil
São Paulo, 19 de novembro de 2011.
Ruby on Rails
Coaching Consultoria
Planejamento
somos referência
9º projeto mais popular
250.000 views/mês
à venda na
Evolução
a tecnologia está evoluindo
e a maneira que fazemos software também...
Fonte: Standish Group, CHAOS Report
16%!
27%!26%!
28%!
34%!
29%!
35%!
32%!
37%!
1994! 1996! 1998! 2000! 2002! 2004! 2006! 2008! 2011!
Evolução da Taxa de Sucessoem Projetos de Software
mas ainda há
63%para avançar
O que causou esta melhora nos últimos 15 anos?
13
1970 1980 1990 2000 2010
70’s
15
Managing the development of large software systemsDr. Winston W. Royce (11 pages)
16
I SYSTE M
I ANALYSIS
PROGRAM DESIGN
I c o o , . o
TESTING
I OPERATIONS
Figure 2. Implementation steps to develop a large computer program for delivery to a customer.
I SYSTE M
I ANALYSIS
PROGRAM DESIGN
I c o o , . o
TESTING
I OPERATIONS
Figure 2. Implementation steps to develop a large computer program for delivery to a customer.
I believe in this concept, but the implementation described above is risky and invites failure. The problem is illustrated in Figure 4. The testing phase which occurs at the end of the development cycle is the first event for which timing, storage, input /output transfers, etc., are experienced as distinguished from analyzed. These phenomena are not precisely analyzable. They are not the solutions to the standard partial differential equations of mathematical physics for instance. Yet if these phenomena fail to satisfy the various external constraints, then invariably a major redesign is required. A simple octal patch or redo of some isolated code wil l not f ix these kinds of diff iculties. The required design changes are l ikely to be so disruptive that the software requirements upon which the design is based and which provides the rationale for everything are violated. Either the requirements must be modif ied, or a substantial change in the design is required. In effect the development process has returned to the origin and one can expect up to a lO0-percent overrun in schedule and/or costs.
One might note that there has been a skipping-over of the analysis and code phases. One cannot, of course, produce software wi thout these steps, but generally these phases are managed wi th relative ease and have l i tt le impact on requirements, design, and testing. In my experience there are whole departments consumed with the analysis of orbi t mechanics, spacecraft att i tude determination, mathematical opt imizat ion of payload activity and so forth, but when these departments have completed their di f f icul t and complex work, the resultant program steps involvea few lines of serial arithmetic code. If in the execution of their d i f f icul t and complex work the analysts have made a mistake, the correction is invariably implemented by a minor change in the code with no disruptive feedback into the other development bases.
However, I believe the illustrated approach to be fundamental ly sound. The remainder of this discussion presents five addit ional features that must be added to this basic approach to eliminate most of the development risks.
329
Engenharia de Software
heavy weight processes
80’s
Custo de mudança
21
Fase do projeto
Cus
to d
e M
udan
ça
a tentativa em 80’s...
23
1980’s
=Controlar Processos Reduzir Custos
TI orientada a Cu$to$
90’s
enfim, reforços...
forte adoção
ProgramaçãoOrientada a Objetos
surgem os primeiroslight weight processeslight
Scrum
CrystalClear
eXtremeProgramming
Adaptive Software Development
Feature DrivenDevelopment
Dynamic Systems Development Method
1995~1996
o resultado...
Custo de mudança
32
“Waterfall” (1970)
Novas abordagens 1990’s
Cus
to d
a M
udan
ça
Tempo
a conclusão...
34
1990’s
=Cicloscurtos
Entregas Constantes de Valor
TI orientada a Geração de Valor
2000’s
O Manifesto Ágil
Individuals and interactions over processes and tools
Fonte: http://agilemanifesto.org
Manifesto for Agile Software Development
We are uncovering better ways of developing software by doing it and helping others do it. Through this work we have come to value:
That is, while there is value in the items onthe right, we value the items on the left more.
Working software over comprehensive documentation
Customer collaboration over contract negotiation
Responding to change over following a plan
2010’s
duas realidadesem projetos...
realidade #1
equipesna realidade #1
equipe de especialistas
passagem de bastão = empurrar o problema
realidade #1
execução do projetona realidade #1
I SYSTE M
I ANALYSIS
PROGRAM DESIGN
I c o o , . o
TESTING
I OPERATIONS
Figure 2. Implementation steps to develop a large computer program for delivery to a customer.
I believe in this concept, but the implementation described above is risky and invites failure. The problem is illustrated in Figure 4. The testing phase which occurs at the end of the development cycle is the first event for which timing, storage, input /output transfers, etc., are experienced as distinguished from analyzed. These phenomena are not precisely analyzable. They are not the solutions to the standard partial differential equations of mathematical physics for instance. Yet if these phenomena fail to satisfy the various external constraints, then invariably a major redesign is required. A simple octal patch or redo of some isolated code wil l not f ix these kinds of diff iculties. The required design changes are l ikely to be so disruptive that the software requirements upon which the design is based and which provides the rationale for everything are violated. Either the requirements must be modif ied, or a substantial change in the design is required. In effect the development process has returned to the origin and one can expect up to a lO0-percent overrun in schedule and/or costs.
One might note that there has been a skipping-over of the analysis and code phases. One cannot, of course, produce software wi thout these steps, but generally these phases are managed wi th relative ease and have l i tt le impact on requirements, design, and testing. In my experience there are whole departments consumed with the analysis of orbi t mechanics, spacecraft att i tude determination, mathematical opt imizat ion of payload activity and so forth, but when these departments have completed their di f f icul t and complex work, the resultant program steps involvea few lines of serial arithmetic code. If in the execution of their d i f f icul t and complex work the analysts have made a mistake, the correction is invariably implemented by a minor change in the code with no disruptive feedback into the other development bases.
However, I believe the illustrated approach to be fundamental ly sound. The remainder of this discussion presents five addit ional features that must be added to this basic approach to eliminate most of the development risks.
329
requisitos mudam
não condiz com os requisitos
sempre atrasa
não há tempo
espero que funcione
realidade #1
realidade #1
ProblemasProblemas
Problemas
Problemas
Problemas
Problemas
Problemas
Problemas
Problemas
Problemas
Problemas
Problemas
Problemas
ProblemasProblemas
Problemas
Projeto
é tarde de mais!:(
lidando com mudançasna realidade #1
• processo lento e desgastante
• change requests
• adendo de contratos
• consome muito tempo e dinheiro
realidade #1
Custo de mudançaC
usto
da
Mud
ança
Tempo
realidade #1
entregasna realidade #1
Requisitos Design Coding IntegraçãoTestes Deploy
25%
% prontorealidade #1
0%
Projeto
Uso
2 meses de projeto
Entrega de Valor
Tempo
Valo
r E
ntre
gue
realidade #1
realidade #2
equipesna realidade #2
realidade #2
Times multi-disciplinaresformados por Generalistas Especialistas
execução do projetona realidade #2
realidade #2
I SYSTE M
I ANALYSIS
PROGRAM DESIGN
I c o o , . o
TESTING
I OPERATIONS
Figure 2. Implementation steps to develop a large computer program for delivery to a customer.
I believe in this concept, but the implementation described above is risky and invites failure. The problem is illustrated in Figure 4. The testing phase which occurs at the end of the development cycle is the first event for which timing, storage, input /output transfers, etc., are experienced as distinguished from analyzed. These phenomena are not precisely analyzable. They are not the solutions to the standard partial differential equations of mathematical physics for instance. Yet if these phenomena fail to satisfy the various external constraints, then invariably a major redesign is required. A simple octal patch or redo of some isolated code wil l not f ix these kinds of diff iculties. The required design changes are l ikely to be so disruptive that the software requirements upon which the design is based and which provides the rationale for everything are violated. Either the requirements must be modif ied, or a substantial change in the design is required. In effect the development process has returned to the origin and one can expect up to a lO0-percent overrun in schedule and/or costs.
One might note that there has been a skipping-over of the analysis and code phases. One cannot, of course, produce software wi thout these steps, but generally these phases are managed wi th relative ease and have l i tt le impact on requirements, design, and testing. In my experience there are whole departments consumed with the analysis of orbi t mechanics, spacecraft att i tude determination, mathematical opt imizat ion of payload activity and so forth, but when these departments have completed their di f f icul t and complex work, the resultant program steps involvea few lines of serial arithmetic code. If in the execution of their d i f f icul t and complex work the analysts have made a mistake, the correction is invariably implemented by a minor change in the code with no disruptive feedback into the other development bases.
However, I believe the illustrated approach to be fundamental ly sound. The remainder of this discussion presents five addit ional features that must be added to this basic approach to eliminate most of the development risks.
329
I SYSTE M
I ANALYSIS
PROGRAM DESIGN
I c o o , . o
TESTING
I OPERATIONS
Figure 2. Implementation steps to develop a large computer program for delivery to a customer.
I believe in this concept, but the implementation described above is risky and invites failure. The problem is illustrated in Figure 4. The testing phase which occurs at the end of the development cycle is the first event for which timing, storage, input /output transfers, etc., are experienced as distinguished from analyzed. These phenomena are not precisely analyzable. They are not the solutions to the standard partial differential equations of mathematical physics for instance. Yet if these phenomena fail to satisfy the various external constraints, then invariably a major redesign is required. A simple octal patch or redo of some isolated code wil l not f ix these kinds of diff iculties. The required design changes are l ikely to be so disruptive that the software requirements upon which the design is based and which provides the rationale for everything are violated. Either the requirements must be modif ied, or a substantial change in the design is required. In effect the development process has returned to the origin and one can expect up to a lO0-percent overrun in schedule and/or costs.
One might note that there has been a skipping-over of the analysis and code phases. One cannot, of course, produce software wi thout these steps, but generally these phases are managed wi th relative ease and have l i tt le impact on requirements, design, and testing. In my experience there are whole departments consumed with the analysis of orbi t mechanics, spacecraft att i tude determination, mathematical opt imizat ion of payload activity and so forth, but when these departments have completed their di f f icul t and complex work, the resultant program steps involvea few lines of serial arithmetic code. If in the execution of their d i f f icul t and complex work the analysts have made a mistake, the correction is invariably implemented by a minor change in the code with no disruptive feedback into the other development bases.
However, I believe the illustrated approach to be fundamental ly sound. The remainder of this discussion presents five addit ional features that must be added to this basic approach to eliminate most of the development risks.
329
I SYSTE M
I ANALYSIS
PROGRAM DESIGN
I c o o , . o
TESTING
I OPERATIONS
Figure 2. Implementation steps to develop a large computer program for delivery to a customer.
I believe in this concept, but the implementation described above is risky and invites failure. The problem is illustrated in Figure 4. The testing phase which occurs at the end of the development cycle is the first event for which timing, storage, input /output transfers, etc., are experienced as distinguished from analyzed. These phenomena are not precisely analyzable. They are not the solutions to the standard partial differential equations of mathematical physics for instance. Yet if these phenomena fail to satisfy the various external constraints, then invariably a major redesign is required. A simple octal patch or redo of some isolated code wil l not f ix these kinds of diff iculties. The required design changes are l ikely to be so disruptive that the software requirements upon which the design is based and which provides the rationale for everything are violated. Either the requirements must be modif ied, or a substantial change in the design is required. In effect the development process has returned to the origin and one can expect up to a lO0-percent overrun in schedule and/or costs.
One might note that there has been a skipping-over of the analysis and code phases. One cannot, of course, produce software wi thout these steps, but generally these phases are managed wi th relative ease and have l i tt le impact on requirements, design, and testing. In my experience there are whole departments consumed with the analysis of orbi t mechanics, spacecraft att i tude determination, mathematical opt imizat ion of payload activity and so forth, but when these departments have completed their di f f icul t and complex work, the resultant program steps involvea few lines of serial arithmetic code. If in the execution of their d i f f icul t and complex work the analysts have made a mistake, the correction is invariably implemented by a minor change in the code with no disruptive feedback into the other development bases.
However, I believe the illustrated approach to be fundamental ly sound. The remainder of this discussion presents five addit ional features that must be added to this basic approach to eliminate most of the development risks.
329
I SYSTE M
I ANALYSIS
PROGRAM DESIGN
I c o o , . o
TESTING
I OPERATIONS
Figure 2. Implementation steps to develop a large computer program for delivery to a customer.
I believe in this concept, but the implementation described above is risky and invites failure. The problem is illustrated in Figure 4. The testing phase which occurs at the end of the development cycle is the first event for which timing, storage, input /output transfers, etc., are experienced as distinguished from analyzed. These phenomena are not precisely analyzable. They are not the solutions to the standard partial differential equations of mathematical physics for instance. Yet if these phenomena fail to satisfy the various external constraints, then invariably a major redesign is required. A simple octal patch or redo of some isolated code wil l not f ix these kinds of diff iculties. The required design changes are l ikely to be so disruptive that the software requirements upon which the design is based and which provides the rationale for everything are violated. Either the requirements must be modif ied, or a substantial change in the design is required. In effect the development process has returned to the origin and one can expect up to a lO0-percent overrun in schedule and/or costs.
One might note that there has been a skipping-over of the analysis and code phases. One cannot, of course, produce software wi thout these steps, but generally these phases are managed wi th relative ease and have l i tt le impact on requirements, design, and testing. In my experience there are whole departments consumed with the analysis of orbi t mechanics, spacecraft att i tude determination, mathematical opt imizat ion of payload activity and so forth, but when these departments have completed their di f f icul t and complex work, the resultant program steps involvea few lines of serial arithmetic code. If in the execution of their d i f f icul t and complex work the analysts have made a mistake, the correction is invariably implemented by a minor change in the code with no disruptive feedback into the other development bases.
However, I believe the illustrated approach to be fundamental ly sound. The remainder of this discussion presents five addit ional features that must be added to this basic approach to eliminate most of the development risks.
329
I SYSTE M
I ANALYSIS
PROGRAM DESIGN
I c o o , . o
TESTING
I OPERATIONS
Figure 2. Implementation steps to develop a large computer program for delivery to a customer.
I believe in this concept, but the implementation described above is risky and invites failure. The problem is illustrated in Figure 4. The testing phase which occurs at the end of the development cycle is the first event for which timing, storage, input /output transfers, etc., are experienced as distinguished from analyzed. These phenomena are not precisely analyzable. They are not the solutions to the standard partial differential equations of mathematical physics for instance. Yet if these phenomena fail to satisfy the various external constraints, then invariably a major redesign is required. A simple octal patch or redo of some isolated code wil l not f ix these kinds of diff iculties. The required design changes are l ikely to be so disruptive that the software requirements upon which the design is based and which provides the rationale for everything are violated. Either the requirements must be modif ied, or a substantial change in the design is required. In effect the development process has returned to the origin and one can expect up to a lO0-percent overrun in schedule and/or costs.
One might note that there has been a skipping-over of the analysis and code phases. One cannot, of course, produce software wi thout these steps, but generally these phases are managed wi th relative ease and have l i tt le impact on requirements, design, and testing. In my experience there are whole departments consumed with the analysis of orbi t mechanics, spacecraft att i tude determination, mathematical opt imizat ion of payload activity and so forth, but when these departments have completed their di f f icul t and complex work, the resultant program steps involvea few lines of serial arithmetic code. If in the execution of their d i f f icul t and complex work the analysts have made a mistake, the correction is invariably implemented by a minor change in the code with no disruptive feedback into the other development bases.
However, I believe the illustrated approach to be fundamental ly sound. The remainder of this discussion presents five addit ional features that must be added to this basic approach to eliminate most of the development risks.
329
I SYSTE M
I ANALYSIS
PROGRAM DESIGN
I c o o , . o
TESTING
I OPERATIONS
Figure 2. Implementation steps to develop a large computer program for delivery to a customer.
I believe in this concept, but the implementation described above is risky and invites failure. The problem is illustrated in Figure 4. The testing phase which occurs at the end of the development cycle is the first event for which timing, storage, input /output transfers, etc., are experienced as distinguished from analyzed. These phenomena are not precisely analyzable. They are not the solutions to the standard partial differential equations of mathematical physics for instance. Yet if these phenomena fail to satisfy the various external constraints, then invariably a major redesign is required. A simple octal patch or redo of some isolated code wil l not f ix these kinds of diff iculties. The required design changes are l ikely to be so disruptive that the software requirements upon which the design is based and which provides the rationale for everything are violated. Either the requirements must be modif ied, or a substantial change in the design is required. In effect the development process has returned to the origin and one can expect up to a lO0-percent overrun in schedule and/or costs.
One might note that there has been a skipping-over of the analysis and code phases. One cannot, of course, produce software wi thout these steps, but generally these phases are managed wi th relative ease and have l i tt le impact on requirements, design, and testing. In my experience there are whole departments consumed with the analysis of orbi t mechanics, spacecraft att i tude determination, mathematical opt imizat ion of payload activity and so forth, but when these departments have completed their di f f icul t and complex work, the resultant program steps involvea few lines of serial arithmetic code. If in the execution of their d i f f icul t and complex work the analysts have made a mistake, the correction is invariably implemented by a minor change in the code with no disruptive feedback into the other development bases.
However, I believe the illustrated approach to be fundamental ly sound. The remainder of this discussion presents five addit ional features that must be added to this basic approach to eliminate most of the development risks.
329
I SYSTE M
I ANALYSIS
PROGRAM DESIGN
I c o o , . o
TESTING
I OPERATIONS
Figure 2. Implementation steps to develop a large computer program for delivery to a customer.
I believe in this concept, but the implementation described above is risky and invites failure. The problem is illustrated in Figure 4. The testing phase which occurs at the end of the development cycle is the first event for which timing, storage, input /output transfers, etc., are experienced as distinguished from analyzed. These phenomena are not precisely analyzable. They are not the solutions to the standard partial differential equations of mathematical physics for instance. Yet if these phenomena fail to satisfy the various external constraints, then invariably a major redesign is required. A simple octal patch or redo of some isolated code wil l not f ix these kinds of diff iculties. The required design changes are l ikely to be so disruptive that the software requirements upon which the design is based and which provides the rationale for everything are violated. Either the requirements must be modif ied, or a substantial change in the design is required. In effect the development process has returned to the origin and one can expect up to a lO0-percent overrun in schedule and/or costs.
One might note that there has been a skipping-over of the analysis and code phases. One cannot, of course, produce software wi thout these steps, but generally these phases are managed wi th relative ease and have l i tt le impact on requirements, design, and testing. In my experience there are whole departments consumed with the analysis of orbi t mechanics, spacecraft att i tude determination, mathematical opt imizat ion of payload activity and so forth, but when these departments have completed their di f f icul t and complex work, the resultant program steps involvea few lines of serial arithmetic code. If in the execution of their d i f f icul t and complex work the analysts have made a mistake, the correction is invariably implemented by a minor change in the code with no disruptive feedback into the other development bases.
However, I believe the illustrated approach to be fundamental ly sound. The remainder of this discussion presents five addit ional features that must be added to this basic approach to eliminate most of the development risks.
329
Sprint 1I SYSTE M
I ANALYSIS
PROGRAM DESIGN
I c o o , . o
TESTING
I OPERATIONS
Figure 2. Implementation steps to develop a large computer program for delivery to a customer.
I believe in this concept, but the implementation described above is risky and invites failure. The problem is illustrated in Figure 4. The testing phase which occurs at the end of the development cycle is the first event for which timing, storage, input /output transfers, etc., are experienced as distinguished from analyzed. These phenomena are not precisely analyzable. They are not the solutions to the standard partial differential equations of mathematical physics for instance. Yet if these phenomena fail to satisfy the various external constraints, then invariably a major redesign is required. A simple octal patch or redo of some isolated code wil l not f ix these kinds of diff iculties. The required design changes are l ikely to be so disruptive that the software requirements upon which the design is based and which provides the rationale for everything are violated. Either the requirements must be modif ied, or a substantial change in the design is required. In effect the development process has returned to the origin and one can expect up to a lO0-percent overrun in schedule and/or costs.
One might note that there has been a skipping-over of the analysis and code phases. One cannot, of course, produce software wi thout these steps, but generally these phases are managed wi th relative ease and have l i tt le impact on requirements, design, and testing. In my experience there are whole departments consumed with the analysis of orbi t mechanics, spacecraft att i tude determination, mathematical opt imizat ion of payload activity and so forth, but when these departments have completed their di f f icul t and complex work, the resultant program steps involvea few lines of serial arithmetic code. If in the execution of their d i f f icul t and complex work the analysts have made a mistake, the correction is invariably implemented by a minor change in the code with no disruptive feedback into the other development bases.
However, I believe the illustrated approach to be fundamental ly sound. The remainder of this discussion presents five addit ional features that must be added to this basic approach to eliminate most of the development risks.
329
I SYSTE M
I ANALYSIS
PROGRAM DESIGN
I c o o , . o
TESTING
I OPERATIONS
Figure 2. Implementation steps to develop a large computer program for delivery to a customer.
I believe in this concept, but the implementation described above is risky and invites failure. The problem is illustrated in Figure 4. The testing phase which occurs at the end of the development cycle is the first event for which timing, storage, input /output transfers, etc., are experienced as distinguished from analyzed. These phenomena are not precisely analyzable. They are not the solutions to the standard partial differential equations of mathematical physics for instance. Yet if these phenomena fail to satisfy the various external constraints, then invariably a major redesign is required. A simple octal patch or redo of some isolated code wil l not f ix these kinds of diff iculties. The required design changes are l ikely to be so disruptive that the software requirements upon which the design is based and which provides the rationale for everything are violated. Either the requirements must be modif ied, or a substantial change in the design is required. In effect the development process has returned to the origin and one can expect up to a lO0-percent overrun in schedule and/or costs.
One might note that there has been a skipping-over of the analysis and code phases. One cannot, of course, produce software wi thout these steps, but generally these phases are managed wi th relative ease and have l i tt le impact on requirements, design, and testing. In my experience there are whole departments consumed with the analysis of orbi t mechanics, spacecraft att i tude determination, mathematical opt imizat ion of payload activity and so forth, but when these departments have completed their di f f icul t and complex work, the resultant program steps involvea few lines of serial arithmetic code. If in the execution of their d i f f icul t and complex work the analysts have made a mistake, the correction is invariably implemented by a minor change in the code with no disruptive feedback into the other development bases.
However, I believe the illustrated approach to be fundamental ly sound. The remainder of this discussion presents five addit ional features that must be added to this basic approach to eliminate most of the development risks.
329
I SYSTE M
I ANALYSIS
PROGRAM DESIGN
I c o o , . o
TESTING
I OPERATIONS
Figure 2. Implementation steps to develop a large computer program for delivery to a customer.
I believe in this concept, but the implementation described above is risky and invites failure. The problem is illustrated in Figure 4. The testing phase which occurs at the end of the development cycle is the first event for which timing, storage, input /output transfers, etc., are experienced as distinguished from analyzed. These phenomena are not precisely analyzable. They are not the solutions to the standard partial differential equations of mathematical physics for instance. Yet if these phenomena fail to satisfy the various external constraints, then invariably a major redesign is required. A simple octal patch or redo of some isolated code wil l not f ix these kinds of diff iculties. The required design changes are l ikely to be so disruptive that the software requirements upon which the design is based and which provides the rationale for everything are violated. Either the requirements must be modif ied, or a substantial change in the design is required. In effect the development process has returned to the origin and one can expect up to a lO0-percent overrun in schedule and/or costs.
One might note that there has been a skipping-over of the analysis and code phases. One cannot, of course, produce software wi thout these steps, but generally these phases are managed wi th relative ease and have l i tt le impact on requirements, design, and testing. In my experience there are whole departments consumed with the analysis of orbi t mechanics, spacecraft att i tude determination, mathematical opt imizat ion of payload activity and so forth, but when these departments have completed their di f f icul t and complex work, the resultant program steps involvea few lines of serial arithmetic code. If in the execution of their d i f f icul t and complex work the analysts have made a mistake, the correction is invariably implemented by a minor change in the code with no disruptive feedback into the other development bases.
However, I believe the illustrated approach to be fundamental ly sound. The remainder of this discussion presents five addit ional features that must be added to this basic approach to eliminate most of the development risks.
329
I SYSTE M
I ANALYSIS
PROGRAM DESIGN
I c o o , . o
TESTING
I OPERATIONS
Figure 2. Implementation steps to develop a large computer program for delivery to a customer.
I believe in this concept, but the implementation described above is risky and invites failure. The problem is illustrated in Figure 4. The testing phase which occurs at the end of the development cycle is the first event for which timing, storage, input /output transfers, etc., are experienced as distinguished from analyzed. These phenomena are not precisely analyzable. They are not the solutions to the standard partial differential equations of mathematical physics for instance. Yet if these phenomena fail to satisfy the various external constraints, then invariably a major redesign is required. A simple octal patch or redo of some isolated code wil l not f ix these kinds of diff iculties. The required design changes are l ikely to be so disruptive that the software requirements upon which the design is based and which provides the rationale for everything are violated. Either the requirements must be modif ied, or a substantial change in the design is required. In effect the development process has returned to the origin and one can expect up to a lO0-percent overrun in schedule and/or costs.
One might note that there has been a skipping-over of the analysis and code phases. One cannot, of course, produce software wi thout these steps, but generally these phases are managed wi th relative ease and have l i tt le impact on requirements, design, and testing. In my experience there are whole departments consumed with the analysis of orbi t mechanics, spacecraft att i tude determination, mathematical opt imizat ion of payload activity and so forth, but when these departments have completed their di f f icul t and complex work, the resultant program steps involvea few lines of serial arithmetic code. If in the execution of their d i f f icul t and complex work the analysts have made a mistake, the correction is invariably implemented by a minor change in the code with no disruptive feedback into the other development bases.
However, I believe the illustrated approach to be fundamental ly sound. The remainder of this discussion presents five addit ional features that must be added to this basic approach to eliminate most of the development risks.
329
I SYSTE M
I ANALYSIS
PROGRAM DESIGN
I c o o , . o
TESTING
I OPERATIONS
Figure 2. Implementation steps to develop a large computer program for delivery to a customer.
I believe in this concept, but the implementation described above is risky and invites failure. The problem is illustrated in Figure 4. The testing phase which occurs at the end of the development cycle is the first event for which timing, storage, input /output transfers, etc., are experienced as distinguished from analyzed. These phenomena are not precisely analyzable. They are not the solutions to the standard partial differential equations of mathematical physics for instance. Yet if these phenomena fail to satisfy the various external constraints, then invariably a major redesign is required. A simple octal patch or redo of some isolated code wil l not f ix these kinds of diff iculties. The required design changes are l ikely to be so disruptive that the software requirements upon which the design is based and which provides the rationale for everything are violated. Either the requirements must be modif ied, or a substantial change in the design is required. In effect the development process has returned to the origin and one can expect up to a lO0-percent overrun in schedule and/or costs.
One might note that there has been a skipping-over of the analysis and code phases. One cannot, of course, produce software wi thout these steps, but generally these phases are managed wi th relative ease and have l i tt le impact on requirements, design, and testing. In my experience there are whole departments consumed with the analysis of orbi t mechanics, spacecraft att i tude determination, mathematical opt imizat ion of payload activity and so forth, but when these departments have completed their di f f icul t and complex work, the resultant program steps involvea few lines of serial arithmetic code. If in the execution of their d i f f icul t and complex work the analysts have made a mistake, the correction is invariably implemented by a minor change in the code with no disruptive feedback into the other development bases.
However, I believe the illustrated approach to be fundamental ly sound. The remainder of this discussion presents five addit ional features that must be added to this basic approach to eliminate most of the development risks.
329
I SYSTE M
I ANALYSIS
PROGRAM DESIGN
I c o o , . o
TESTING
I OPERATIONS
Figure 2. Implementation steps to develop a large computer program for delivery to a customer.
I believe in this concept, but the implementation described above is risky and invites failure. The problem is illustrated in Figure 4. The testing phase which occurs at the end of the development cycle is the first event for which timing, storage, input /output transfers, etc., are experienced as distinguished from analyzed. These phenomena are not precisely analyzable. They are not the solutions to the standard partial differential equations of mathematical physics for instance. Yet if these phenomena fail to satisfy the various external constraints, then invariably a major redesign is required. A simple octal patch or redo of some isolated code wil l not f ix these kinds of diff iculties. The required design changes are l ikely to be so disruptive that the software requirements upon which the design is based and which provides the rationale for everything are violated. Either the requirements must be modif ied, or a substantial change in the design is required. In effect the development process has returned to the origin and one can expect up to a lO0-percent overrun in schedule and/or costs.
One might note that there has been a skipping-over of the analysis and code phases. One cannot, of course, produce software wi thout these steps, but generally these phases are managed wi th relative ease and have l i tt le impact on requirements, design, and testing. In my experience there are whole departments consumed with the analysis of orbi t mechanics, spacecraft att i tude determination, mathematical opt imizat ion of payload activity and so forth, but when these departments have completed their di f f icul t and complex work, the resultant program steps involvea few lines of serial arithmetic code. If in the execution of their d i f f icul t and complex work the analysts have made a mistake, the correction is invariably implemented by a minor change in the code with no disruptive feedback into the other development bases.
However, I believe the illustrated approach to be fundamental ly sound. The remainder of this discussion presents five addit ional features that must be added to this basic approach to eliminate most of the development risks.
329
I SYSTE M
I ANALYSIS
PROGRAM DESIGN
I c o o , . o
TESTING
I OPERATIONS
Figure 2. Implementation steps to develop a large computer program for delivery to a customer.
I believe in this concept, but the implementation described above is risky and invites failure. The problem is illustrated in Figure 4. The testing phase which occurs at the end of the development cycle is the first event for which timing, storage, input /output transfers, etc., are experienced as distinguished from analyzed. These phenomena are not precisely analyzable. They are not the solutions to the standard partial differential equations of mathematical physics for instance. Yet if these phenomena fail to satisfy the various external constraints, then invariably a major redesign is required. A simple octal patch or redo of some isolated code wil l not f ix these kinds of diff iculties. The required design changes are l ikely to be so disruptive that the software requirements upon which the design is based and which provides the rationale for everything are violated. Either the requirements must be modif ied, or a substantial change in the design is required. In effect the development process has returned to the origin and one can expect up to a lO0-percent overrun in schedule and/or costs.
One might note that there has been a skipping-over of the analysis and code phases. One cannot, of course, produce software wi thout these steps, but generally these phases are managed wi th relative ease and have l i tt le impact on requirements, design, and testing. In my experience there are whole departments consumed with the analysis of orbi t mechanics, spacecraft att i tude determination, mathematical opt imizat ion of payload activity and so forth, but when these departments have completed their di f f icul t and complex work, the resultant program steps involvea few lines of serial arithmetic code. If in the execution of their d i f f icul t and complex work the analysts have made a mistake, the correction is invariably implemented by a minor change in the code with no disruptive feedback into the other development bases.
However, I believe the illustrated approach to be fundamental ly sound. The remainder of this discussion presents five addit ional features that must be added to this basic approach to eliminate most of the development risks.
329
Sprint 2I SYSTE M
I ANALYSIS
PROGRAM DESIGN
I c o o , . o
TESTING
I OPERATIONS
Figure 2. Implementation steps to develop a large computer program for delivery to a customer.
I believe in this concept, but the implementation described above is risky and invites failure. The problem is illustrated in Figure 4. The testing phase which occurs at the end of the development cycle is the first event for which timing, storage, input /output transfers, etc., are experienced as distinguished from analyzed. These phenomena are not precisely analyzable. They are not the solutions to the standard partial differential equations of mathematical physics for instance. Yet if these phenomena fail to satisfy the various external constraints, then invariably a major redesign is required. A simple octal patch or redo of some isolated code wil l not f ix these kinds of diff iculties. The required design changes are l ikely to be so disruptive that the software requirements upon which the design is based and which provides the rationale for everything are violated. Either the requirements must be modif ied, or a substantial change in the design is required. In effect the development process has returned to the origin and one can expect up to a lO0-percent overrun in schedule and/or costs.
One might note that there has been a skipping-over of the analysis and code phases. One cannot, of course, produce software wi thout these steps, but generally these phases are managed wi th relative ease and have l i tt le impact on requirements, design, and testing. In my experience there are whole departments consumed with the analysis of orbi t mechanics, spacecraft att i tude determination, mathematical opt imizat ion of payload activity and so forth, but when these departments have completed their di f f icul t and complex work, the resultant program steps involvea few lines of serial arithmetic code. If in the execution of their d i f f icul t and complex work the analysts have made a mistake, the correction is invariably implemented by a minor change in the code with no disruptive feedback into the other development bases.
However, I believe the illustrated approach to be fundamental ly sound. The remainder of this discussion presents five addit ional features that must be added to this basic approach to eliminate most of the development risks.
329
I SYSTE M
I ANALYSIS
PROGRAM DESIGN
I c o o , . o
TESTING
I OPERATIONS
Figure 2. Implementation steps to develop a large computer program for delivery to a customer.
I believe in this concept, but the implementation described above is risky and invites failure. The problem is illustrated in Figure 4. The testing phase which occurs at the end of the development cycle is the first event for which timing, storage, input /output transfers, etc., are experienced as distinguished from analyzed. These phenomena are not precisely analyzable. They are not the solutions to the standard partial differential equations of mathematical physics for instance. Yet if these phenomena fail to satisfy the various external constraints, then invariably a major redesign is required. A simple octal patch or redo of some isolated code wil l not f ix these kinds of diff iculties. The required design changes are l ikely to be so disruptive that the software requirements upon which the design is based and which provides the rationale for everything are violated. Either the requirements must be modif ied, or a substantial change in the design is required. In effect the development process has returned to the origin and one can expect up to a lO0-percent overrun in schedule and/or costs.
One might note that there has been a skipping-over of the analysis and code phases. One cannot, of course, produce software wi thout these steps, but generally these phases are managed wi th relative ease and have l i tt le impact on requirements, design, and testing. In my experience there are whole departments consumed with the analysis of orbi t mechanics, spacecraft att i tude determination, mathematical opt imizat ion of payload activity and so forth, but when these departments have completed their di f f icul t and complex work, the resultant program steps involvea few lines of serial arithmetic code. If in the execution of their d i f f icul t and complex work the analysts have made a mistake, the correction is invariably implemented by a minor change in the code with no disruptive feedback into the other development bases.
However, I believe the illustrated approach to be fundamental ly sound. The remainder of this discussion presents five addit ional features that must be added to this basic approach to eliminate most of the development risks.
329
I SYSTE M
I ANALYSIS
PROGRAM DESIGN
I c o o , . o
TESTING
I OPERATIONS
Figure 2. Implementation steps to develop a large computer program for delivery to a customer.
I believe in this concept, but the implementation described above is risky and invites failure. The problem is illustrated in Figure 4. The testing phase which occurs at the end of the development cycle is the first event for which timing, storage, input /output transfers, etc., are experienced as distinguished from analyzed. These phenomena are not precisely analyzable. They are not the solutions to the standard partial differential equations of mathematical physics for instance. Yet if these phenomena fail to satisfy the various external constraints, then invariably a major redesign is required. A simple octal patch or redo of some isolated code wil l not f ix these kinds of diff iculties. The required design changes are l ikely to be so disruptive that the software requirements upon which the design is based and which provides the rationale for everything are violated. Either the requirements must be modif ied, or a substantial change in the design is required. In effect the development process has returned to the origin and one can expect up to a lO0-percent overrun in schedule and/or costs.
One might note that there has been a skipping-over of the analysis and code phases. One cannot, of course, produce software wi thout these steps, but generally these phases are managed wi th relative ease and have l i tt le impact on requirements, design, and testing. In my experience there are whole departments consumed with the analysis of orbi t mechanics, spacecraft att i tude determination, mathematical opt imizat ion of payload activity and so forth, but when these departments have completed their di f f icul t and complex work, the resultant program steps involvea few lines of serial arithmetic code. If in the execution of their d i f f icul t and complex work the analysts have made a mistake, the correction is invariably implemented by a minor change in the code with no disruptive feedback into the other development bases.
However, I believe the illustrated approach to be fundamental ly sound. The remainder of this discussion presents five addit ional features that must be added to this basic approach to eliminate most of the development risks.
329
I SYSTE M
I ANALYSIS
PROGRAM DESIGN
I c o o , . o
TESTING
I OPERATIONS
Figure 2. Implementation steps to develop a large computer program for delivery to a customer.
I believe in this concept, but the implementation described above is risky and invites failure. The problem is illustrated in Figure 4. The testing phase which occurs at the end of the development cycle is the first event for which timing, storage, input /output transfers, etc., are experienced as distinguished from analyzed. These phenomena are not precisely analyzable. They are not the solutions to the standard partial differential equations of mathematical physics for instance. Yet if these phenomena fail to satisfy the various external constraints, then invariably a major redesign is required. A simple octal patch or redo of some isolated code wil l not f ix these kinds of diff iculties. The required design changes are l ikely to be so disruptive that the software requirements upon which the design is based and which provides the rationale for everything are violated. Either the requirements must be modif ied, or a substantial change in the design is required. In effect the development process has returned to the origin and one can expect up to a lO0-percent overrun in schedule and/or costs.
One might note that there has been a skipping-over of the analysis and code phases. One cannot, of course, produce software wi thout these steps, but generally these phases are managed wi th relative ease and have l i tt le impact on requirements, design, and testing. In my experience there are whole departments consumed with the analysis of orbi t mechanics, spacecraft att i tude determination, mathematical opt imizat ion of payload activity and so forth, but when these departments have completed their di f f icul t and complex work, the resultant program steps involvea few lines of serial arithmetic code. If in the execution of their d i f f icul t and complex work the analysts have made a mistake, the correction is invariably implemented by a minor change in the code with no disruptive feedback into the other development bases.
However, I believe the illustrated approach to be fundamental ly sound. The remainder of this discussion presents five addit ional features that must be added to this basic approach to eliminate most of the development risks.
329
I SYSTE M
I ANALYSIS
PROGRAM DESIGN
I c o o , . o
TESTING
I OPERATIONS
Figure 2. Implementation steps to develop a large computer program for delivery to a customer.
I believe in this concept, but the implementation described above is risky and invites failure. The problem is illustrated in Figure 4. The testing phase which occurs at the end of the development cycle is the first event for which timing, storage, input /output transfers, etc., are experienced as distinguished from analyzed. These phenomena are not precisely analyzable. They are not the solutions to the standard partial differential equations of mathematical physics for instance. Yet if these phenomena fail to satisfy the various external constraints, then invariably a major redesign is required. A simple octal patch or redo of some isolated code wil l not f ix these kinds of diff iculties. The required design changes are l ikely to be so disruptive that the software requirements upon which the design is based and which provides the rationale for everything are violated. Either the requirements must be modif ied, or a substantial change in the design is required. In effect the development process has returned to the origin and one can expect up to a lO0-percent overrun in schedule and/or costs.
One might note that there has been a skipping-over of the analysis and code phases. One cannot, of course, produce software wi thout these steps, but generally these phases are managed wi th relative ease and have l i tt le impact on requirements, design, and testing. In my experience there are whole departments consumed with the analysis of orbi t mechanics, spacecraft att i tude determination, mathematical opt imizat ion of payload activity and so forth, but when these departments have completed their di f f icul t and complex work, the resultant program steps involvea few lines of serial arithmetic code. If in the execution of their d i f f icul t and complex work the analysts have made a mistake, the correction is invariably implemented by a minor change in the code with no disruptive feedback into the other development bases.
However, I believe the illustrated approach to be fundamental ly sound. The remainder of this discussion presents five addit ional features that must be added to this basic approach to eliminate most of the development risks.
329
I SYSTE M
I ANALYSIS
PROGRAM DESIGN
I c o o , . o
TESTING
I OPERATIONS
Figure 2. Implementation steps to develop a large computer program for delivery to a customer.
I believe in this concept, but the implementation described above is risky and invites failure. The problem is illustrated in Figure 4. The testing phase which occurs at the end of the development cycle is the first event for which timing, storage, input /output transfers, etc., are experienced as distinguished from analyzed. These phenomena are not precisely analyzable. They are not the solutions to the standard partial differential equations of mathematical physics for instance. Yet if these phenomena fail to satisfy the various external constraints, then invariably a major redesign is required. A simple octal patch or redo of some isolated code wil l not f ix these kinds of diff iculties. The required design changes are l ikely to be so disruptive that the software requirements upon which the design is based and which provides the rationale for everything are violated. Either the requirements must be modif ied, or a substantial change in the design is required. In effect the development process has returned to the origin and one can expect up to a lO0-percent overrun in schedule and/or costs.
One might note that there has been a skipping-over of the analysis and code phases. One cannot, of course, produce software wi thout these steps, but generally these phases are managed wi th relative ease and have l i tt le impact on requirements, design, and testing. In my experience there are whole departments consumed with the analysis of orbi t mechanics, spacecraft att i tude determination, mathematical opt imizat ion of payload activity and so forth, but when these departments have completed their di f f icul t and complex work, the resultant program steps involvea few lines of serial arithmetic code. If in the execution of their d i f f icul t and complex work the analysts have made a mistake, the correction is invariably implemented by a minor change in the code with no disruptive feedback into the other development bases.
However, I believe the illustrated approach to be fundamental ly sound. The remainder of this discussion presents five addit ional features that must be added to this basic approach to eliminate most of the development risks.
329
I SYSTE M
I ANALYSIS
PROGRAM DESIGN
I c o o , . o
TESTING
I OPERATIONS
Figure 2. Implementation steps to develop a large computer program for delivery to a customer.
I believe in this concept, but the implementation described above is risky and invites failure. The problem is illustrated in Figure 4. The testing phase which occurs at the end of the development cycle is the first event for which timing, storage, input /output transfers, etc., are experienced as distinguished from analyzed. These phenomena are not precisely analyzable. They are not the solutions to the standard partial differential equations of mathematical physics for instance. Yet if these phenomena fail to satisfy the various external constraints, then invariably a major redesign is required. A simple octal patch or redo of some isolated code wil l not f ix these kinds of diff iculties. The required design changes are l ikely to be so disruptive that the software requirements upon which the design is based and which provides the rationale for everything are violated. Either the requirements must be modif ied, or a substantial change in the design is required. In effect the development process has returned to the origin and one can expect up to a lO0-percent overrun in schedule and/or costs.
One might note that there has been a skipping-over of the analysis and code phases. One cannot, of course, produce software wi thout these steps, but generally these phases are managed wi th relative ease and have l i tt le impact on requirements, design, and testing. In my experience there are whole departments consumed with the analysis of orbi t mechanics, spacecraft att i tude determination, mathematical opt imizat ion of payload activity and so forth, but when these departments have completed their di f f icul t and complex work, the resultant program steps involvea few lines of serial arithmetic code. If in the execution of their d i f f icul t and complex work the analysts have made a mistake, the correction is invariably implemented by a minor change in the code with no disruptive feedback into the other development bases.
However, I believe the illustrated approach to be fundamental ly sound. The remainder of this discussion presents five addit ional features that must be added to this basic approach to eliminate most of the development risks.
329
Sprint ...I SYSTE M
I ANALYSIS
PROGRAM DESIGN
I c o o , . o
TESTING
I OPERATIONS
Figure 2. Implementation steps to develop a large computer program for delivery to a customer.
I believe in this concept, but the implementation described above is risky and invites failure. The problem is illustrated in Figure 4. The testing phase which occurs at the end of the development cycle is the first event for which timing, storage, input /output transfers, etc., are experienced as distinguished from analyzed. These phenomena are not precisely analyzable. They are not the solutions to the standard partial differential equations of mathematical physics for instance. Yet if these phenomena fail to satisfy the various external constraints, then invariably a major redesign is required. A simple octal patch or redo of some isolated code wil l not f ix these kinds of diff iculties. The required design changes are l ikely to be so disruptive that the software requirements upon which the design is based and which provides the rationale for everything are violated. Either the requirements must be modif ied, or a substantial change in the design is required. In effect the development process has returned to the origin and one can expect up to a lO0-percent overrun in schedule and/or costs.
One might note that there has been a skipping-over of the analysis and code phases. One cannot, of course, produce software wi thout these steps, but generally these phases are managed wi th relative ease and have l i tt le impact on requirements, design, and testing. In my experience there are whole departments consumed with the analysis of orbi t mechanics, spacecraft att i tude determination, mathematical opt imizat ion of payload activity and so forth, but when these departments have completed their di f f icul t and complex work, the resultant program steps involvea few lines of serial arithmetic code. If in the execution of their d i f f icul t and complex work the analysts have made a mistake, the correction is invariably implemented by a minor change in the code with no disruptive feedback into the other development bases.
However, I believe the illustrated approach to be fundamental ly sound. The remainder of this discussion presents five addit ional features that must be added to this basic approach to eliminate most of the development risks.
329
I SYSTE M
I ANALYSIS
PROGRAM DESIGN
I c o o , . o
TESTING
I OPERATIONS
Figure 2. Implementation steps to develop a large computer program for delivery to a customer.
I believe in this concept, but the implementation described above is risky and invites failure. The problem is illustrated in Figure 4. The testing phase which occurs at the end of the development cycle is the first event for which timing, storage, input /output transfers, etc., are experienced as distinguished from analyzed. These phenomena are not precisely analyzable. They are not the solutions to the standard partial differential equations of mathematical physics for instance. Yet if these phenomena fail to satisfy the various external constraints, then invariably a major redesign is required. A simple octal patch or redo of some isolated code wil l not f ix these kinds of diff iculties. The required design changes are l ikely to be so disruptive that the software requirements upon which the design is based and which provides the rationale for everything are violated. Either the requirements must be modif ied, or a substantial change in the design is required. In effect the development process has returned to the origin and one can expect up to a lO0-percent overrun in schedule and/or costs.
One might note that there has been a skipping-over of the analysis and code phases. One cannot, of course, produce software wi thout these steps, but generally these phases are managed wi th relative ease and have l i tt le impact on requirements, design, and testing. In my experience there are whole departments consumed with the analysis of orbi t mechanics, spacecraft att i tude determination, mathematical opt imizat ion of payload activity and so forth, but when these departments have completed their di f f icul t and complex work, the resultant program steps involvea few lines of serial arithmetic code. If in the execution of their d i f f icul t and complex work the analysts have made a mistake, the correction is invariably implemented by a minor change in the code with no disruptive feedback into the other development bases.
However, I believe the illustrated approach to be fundamental ly sound. The remainder of this discussion presents five addit ional features that must be added to this basic approach to eliminate most of the development risks.
329
I SYSTE M
I ANALYSIS
PROGRAM DESIGN
I c o o , . o
TESTING
I OPERATIONS
Figure 2. Implementation steps to develop a large computer program for delivery to a customer.
I believe in this concept, but the implementation described above is risky and invites failure. The problem is illustrated in Figure 4. The testing phase which occurs at the end of the development cycle is the first event for which timing, storage, input /output transfers, etc., are experienced as distinguished from analyzed. These phenomena are not precisely analyzable. They are not the solutions to the standard partial differential equations of mathematical physics for instance. Yet if these phenomena fail to satisfy the various external constraints, then invariably a major redesign is required. A simple octal patch or redo of some isolated code wil l not f ix these kinds of diff iculties. The required design changes are l ikely to be so disruptive that the software requirements upon which the design is based and which provides the rationale for everything are violated. Either the requirements must be modif ied, or a substantial change in the design is required. In effect the development process has returned to the origin and one can expect up to a lO0-percent overrun in schedule and/or costs.
One might note that there has been a skipping-over of the analysis and code phases. One cannot, of course, produce software wi thout these steps, but generally these phases are managed wi th relative ease and have l i tt le impact on requirements, design, and testing. In my experience there are whole departments consumed with the analysis of orbi t mechanics, spacecraft att i tude determination, mathematical opt imizat ion of payload activity and so forth, but when these departments have completed their di f f icul t and complex work, the resultant program steps involvea few lines of serial arithmetic code. If in the execution of their d i f f icul t and complex work the analysts have made a mistake, the correction is invariably implemented by a minor change in the code with no disruptive feedback into the other development bases.
However, I believe the illustrated approach to be fundamental ly sound. The remainder of this discussion presents five addit ional features that must be added to this basic approach to eliminate most of the development risks.
329
I SYSTE M
I ANALYSIS
PROGRAM DESIGN
I c o o , . o
TESTING
I OPERATIONS
Figure 2. Implementation steps to develop a large computer program for delivery to a customer.
I believe in this concept, but the implementation described above is risky and invites failure. The problem is illustrated in Figure 4. The testing phase which occurs at the end of the development cycle is the first event for which timing, storage, input /output transfers, etc., are experienced as distinguished from analyzed. These phenomena are not precisely analyzable. They are not the solutions to the standard partial differential equations of mathematical physics for instance. Yet if these phenomena fail to satisfy the various external constraints, then invariably a major redesign is required. A simple octal patch or redo of some isolated code wil l not f ix these kinds of diff iculties. The required design changes are l ikely to be so disruptive that the software requirements upon which the design is based and which provides the rationale for everything are violated. Either the requirements must be modif ied, or a substantial change in the design is required. In effect the development process has returned to the origin and one can expect up to a lO0-percent overrun in schedule and/or costs.
One might note that there has been a skipping-over of the analysis and code phases. One cannot, of course, produce software wi thout these steps, but generally these phases are managed wi th relative ease and have l i tt le impact on requirements, design, and testing. In my experience there are whole departments consumed with the analysis of orbi t mechanics, spacecraft att i tude determination, mathematical opt imizat ion of payload activity and so forth, but when these departments have completed their di f f icul t and complex work, the resultant program steps involvea few lines of serial arithmetic code. If in the execution of their d i f f icul t and complex work the analysts have made a mistake, the correction is invariably implemented by a minor change in the code with no disruptive feedback into the other development bases.
However, I believe the illustrated approach to be fundamental ly sound. The remainder of this discussion presents five addit ional features that must be added to this basic approach to eliminate most of the development risks.
329
I SYSTE M
I ANALYSIS
PROGRAM DESIGN
I c o o , . o
TESTING
I OPERATIONS
Figure 2. Implementation steps to develop a large computer program for delivery to a customer.
I believe in this concept, but the implementation described above is risky and invites failure. The problem is illustrated in Figure 4. The testing phase which occurs at the end of the development cycle is the first event for which timing, storage, input /output transfers, etc., are experienced as distinguished from analyzed. These phenomena are not precisely analyzable. They are not the solutions to the standard partial differential equations of mathematical physics for instance. Yet if these phenomena fail to satisfy the various external constraints, then invariably a major redesign is required. A simple octal patch or redo of some isolated code wil l not f ix these kinds of diff iculties. The required design changes are l ikely to be so disruptive that the software requirements upon which the design is based and which provides the rationale for everything are violated. Either the requirements must be modif ied, or a substantial change in the design is required. In effect the development process has returned to the origin and one can expect up to a lO0-percent overrun in schedule and/or costs.
One might note that there has been a skipping-over of the analysis and code phases. One cannot, of course, produce software wi thout these steps, but generally these phases are managed wi th relative ease and have l i tt le impact on requirements, design, and testing. In my experience there are whole departments consumed with the analysis of orbi t mechanics, spacecraft att i tude determination, mathematical opt imizat ion of payload activity and so forth, but when these departments have completed their di f f icul t and complex work, the resultant program steps involvea few lines of serial arithmetic code. If in the execution of their d i f f icul t and complex work the analysts have made a mistake, the correction is invariably implemented by a minor change in the code with no disruptive feedback into the other development bases.
However, I believe the illustrated approach to be fundamental ly sound. The remainder of this discussion presents five addit ional features that must be added to this basic approach to eliminate most of the development risks.
329
I SYSTE M
I ANALYSIS
PROGRAM DESIGN
I c o o , . o
TESTING
I OPERATIONS
Figure 2. Implementation steps to develop a large computer program for delivery to a customer.
I believe in this concept, but the implementation described above is risky and invites failure. The problem is illustrated in Figure 4. The testing phase which occurs at the end of the development cycle is the first event for which timing, storage, input /output transfers, etc., are experienced as distinguished from analyzed. These phenomena are not precisely analyzable. They are not the solutions to the standard partial differential equations of mathematical physics for instance. Yet if these phenomena fail to satisfy the various external constraints, then invariably a major redesign is required. A simple octal patch or redo of some isolated code wil l not f ix these kinds of diff iculties. The required design changes are l ikely to be so disruptive that the software requirements upon which the design is based and which provides the rationale for everything are violated. Either the requirements must be modif ied, or a substantial change in the design is required. In effect the development process has returned to the origin and one can expect up to a lO0-percent overrun in schedule and/or costs.
One might note that there has been a skipping-over of the analysis and code phases. One cannot, of course, produce software wi thout these steps, but generally these phases are managed wi th relative ease and have l i tt le impact on requirements, design, and testing. In my experience there are whole departments consumed with the analysis of orbi t mechanics, spacecraft att i tude determination, mathematical opt imizat ion of payload activity and so forth, but when these departments have completed their di f f icul t and complex work, the resultant program steps involvea few lines of serial arithmetic code. If in the execution of their d i f f icul t and complex work the analysts have made a mistake, the correction is invariably implemented by a minor change in the code with no disruptive feedback into the other development bases.
However, I believe the illustrated approach to be fundamental ly sound. The remainder of this discussion presents five addit ional features that must be added to this basic approach to eliminate most of the development risks.
329
I SYSTE M
I ANALYSIS
PROGRAM DESIGN
I c o o , . o
TESTING
I OPERATIONS
Figure 2. Implementation steps to develop a large computer program for delivery to a customer.
I believe in this concept, but the implementation described above is risky and invites failure. The problem is illustrated in Figure 4. The testing phase which occurs at the end of the development cycle is the first event for which timing, storage, input /output transfers, etc., are experienced as distinguished from analyzed. These phenomena are not precisely analyzable. They are not the solutions to the standard partial differential equations of mathematical physics for instance. Yet if these phenomena fail to satisfy the various external constraints, then invariably a major redesign is required. A simple octal patch or redo of some isolated code wil l not f ix these kinds of diff iculties. The required design changes are l ikely to be so disruptive that the software requirements upon which the design is based and which provides the rationale for everything are violated. Either the requirements must be modif ied, or a substantial change in the design is required. In effect the development process has returned to the origin and one can expect up to a lO0-percent overrun in schedule and/or costs.
One might note that there has been a skipping-over of the analysis and code phases. One cannot, of course, produce software wi thout these steps, but generally these phases are managed wi th relative ease and have l i tt le impact on requirements, design, and testing. In my experience there are whole departments consumed with the analysis of orbi t mechanics, spacecraft att i tude determination, mathematical opt imizat ion of payload activity and so forth, but when these departments have completed their di f f icul t and complex work, the resultant program steps involvea few lines of serial arithmetic code. If in the execution of their d i f f icul t and complex work the analysts have made a mistake, the correction is invariably implemented by a minor change in the code with no disruptive feedback into the other development bases.
However, I believe the illustrated approach to be fundamental ly sound. The remainder of this discussion presents five addit ional features that must be added to this basic approach to eliminate most of the development risks.
329
Sprint n
realidade #2
ProblemasProblemas
Problemas
Problemas
Problemas
Problemas
Problemas
ProblemasProblemas
Problemas
Problemas
Problemas
Problemas
Problemas Problemas
Problemas
Projeto
=D
lidando com mudançasna realidade #1
• é rápido e indolor
• re-priorizar o backlog (lista de features)
• reunião de sprint planning
• resolve-se tudo em apenas uma reunião
realidade #1
Custo de mudançaC
usto
da
Mud
ança
Tempo
realidade #2
realidade #2 (metodologias ágeis)
realidade #1
entregasna realidade #2
25%
% prontorealidade #2
Projeto
Uso
2 meses de projeto
~25%
Entrega de Valor
Tempo
Valo
r E
ntre
gue
realidade #2
realidade #2 (metodologias ágeis)
realidade #1
faz sentido?
Fonte: Standish Group, CHAOS Report
16%!
27%!26%!
28%!
34%!
29%!
35%!
32%!
37%!
1994! 1996! 1998! 2000! 2002! 2004! 2006! 2008! 2011!
Evolução da Taxa de Sucessoem Projetos de Software
Metodologias Ágeis
Qual é melhor?
Lean Scrum XPvs. vs.
Lean - origens
• resposta da Toyota para sua crise, 1950
• precisava de “cash” no caixa (reduzir o inventário)
• reduzir custos
• melhorar qualidade
Lean
• Pull vs. Push Systems
• Kanban
• Pensamento Sistêmico
• Fluxo Equilibrado
• Células de Trabalho
• Melhoria Contínua
Scrum!"#$%&'()*+,"(
-&"%.(/01',"(
23%45,(
!"#$%&'()*&+,#-( ./"01'()*&+,#-(
.01&"#102*34#($#(567( 809'*(/*"*(
:7,;#"0*9(
<7,7*97(!,*1101-( ./"01'(!,*1101-( =*0,>(?9@( =76#( <7'"#9/7&5A*(
.#BC*"7(D%1&0#1*,(
Scrum
XP
• Test Driven Development
• Integração Contínua
• Entendimento Comum
• Pair-programming
• Ritmo sustentável
Qual é melhor?
Lean Scrum XPvs. vs.
É melhor!
Lean Scrum XP+ +
Lean + Scrum + XP
Tradicional Agileplanejar para antecipar “todos” os problemas
detectar problemase remover impedimentos
decisões são tomadaso quanto antes
decisões são adidaso máximo possível
passagem de bastãoentre especialistas
equipe unificadae multi-disciplinar
the big release(feedback tarde)
entregas contínuas(feedback contínuo)
perde-se tempo comnegociação com o cliente
gera-se valor comcolaboração com o cliente
obedecer o processo para controlar custos
ajustar o processo para otimizar a entregar de valor
seguir um plano responder à mudanças
vs.
Quem usa Agile?
http://www.slideshare.net/sgreene/scrum-gathering-2008-stockholm-salesforcecom-presentation
2000 2001 2002 2003 2004 2005 2006 2007
Features Delivered per Team
Days between Major Releases
Transformation Results
+94 Increase in feature requests delivered -
2007 v. 2006
%
+38 Increase in feature requests delivered per
developer - 2007 v. 2006
%
Agile has delivered total visibility, total transparency and unbelievable productivity! a complete win! ”
Steve Fisher Sr. Vice President, Platform Product
Management Salesforce.com
“
568% more value
delivered in the first year
of being agile.
fonte: Greene and Fry 2008.
