Software Engineering Process I Process Definition

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Software Engineering Process IProcess Definition

• INFO 636
• Glenn Booker

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Defining Processes

• Weve mostly assumed that processes for
  developing software have been provided (such as
  the scripts)
• Now focus a little more on the creation of
  processes, or the refinement of existing
  processes to meet new circumstances

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Process versus Procedure

• Terminology note a process is assumed to be a
  larger set of activities, and hence more complex
  than a procedure
• A procedure is defined to the detailed
  step-by-step instructions level
• A process is defined in terms of the major
  activities needed, some process steps may be
  defined in procedures

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Process Familiarity

• To be able to define a process, you either need
  to be familiar with its activities, or have
  someone readily available who is
• Processes not only define what is needed to meet
  the goal of the process, but also to meet larger
  management objectives (plan, track, measure, etc.)

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Process Objectives

• Processes, in keeping with process maturity
  goals, should be
• Defined in writing somewhere
• Repeatable able to be performed consistently
  over and over
• Measurable so we can assess key aspects of the
  process and improve on them

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Process Elements

• Processes need
• A script or description of the major steps
  involved in performing the process
• Forms, where appropriate, to help ensure
  consistent data gathering
• Standards to help guide common decisions (like
  the defect and review standards)
• Ability to improve (like the PIP form)

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Process Formats

• Many ways have been developed to document
  processes
• Here is one I used frequently
• Processes need to be as simple as possible
  people wont read complex documents if they can
  avoid them
• The technique cited here is information mapping,
  by Horn

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Information Mapping

• Information mapping follows some basic principles
• Chunking group actions into manageable chunks
  of activity
• Relevance only cite relevant activities, and
  put similar things together
• Labeling Label each chunk name it

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Information Mapping

• Consistency make sure to use consistent
  terminology, names for each chunk, organizational
  references, and formatting
• Graphics use graphics where possible to help
  show what you mean
• Detail use an appropriate level of detail for
  your audience
• Hierarchy group chunks by topic, and label each
  topic

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Process Definition

• (This is a departure from the text)
• Process definition typically starts with
  assessing the inputs needed to start the process,
  and determining the outputs the process should
  produce
• Then work out the steps needed to get from the
  inputs to the outputs
• Are there processing options to consider?

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Process Definition

• Look for the trigger, or event that tells when
  the process should start
• Look for products from the process
• What stuff should someone see or use to perform
  this process?
• Look for connections to other processes
• What comes before or after this process?

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Process Definition

• Look for things to measure
• Any process can measure how often its performed,
  how long it takes to perform
• Is there a size, quantity, or quality of the
  stuff produced by the process?
• Look for review and approval steps in the
  process
• Who verifies the process outputs?

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Process Definition

• Ask who performs each step of the process the
  answers may be insightful
• For complex process steps, you can cite detailed
  procedures (scripts) for performing steps within
  the process
• Look for the policy or organization mission that
  authorizes the process to occur

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Personal Process

• The previous four slides can be used for any
  kind of process definition
• Here, Humphrey uses a process improvement-based
  process to define personal processes
• Determine your needs and their priorities
• Define process goals, objectives, and quality
  criteria

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Personal Process

• Assess your current process maturity
• Assess your desired or target process
• Establish a strategy to get from current to
  desired process
• Define your initial processes
• Validate (test) your initial process
• Keep improving your process

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Process Phases

• When ready to define your process, the steps
  outlined earlier are typically used
• Define purpose of the process
• Define who performs the process
• Establish entry criteria
• Define the process tasks
• Define exit criteria when are you done?
• What is the next phase?

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Process Definition Concerns

• A key to establishing a good set of processes is
  to use the right level of detail consistently
• Too much detail wastes time
• Too little detail allows the correct process to
  become forgotten
• Often start simply and add details where needed

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Process Evolution

• Processes should be allowed to evolve over time
• Expect that you will tweak them periodically to
  make them work better, refine measurements, etc.
• The initial process should pretty well match
  what you were originally doing
• The target process is the final objective

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Process Development Process

• You can even define a process for developing
  processes
• Often helpful for a process improvement team
  (SEPG) to follow such a process
• Like any other process, measure the time spent on
  developing and refining processes, and your
  productivity in creating them (e.g. pages/hour)

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Process Development Process

• For a large organization starting from scratch
  (no processes), you can use an estimation form
  like on page 465
• Like the infamous C39/N39, it uses proxies to
  estimate the time needed
• Based on historic data, you can keep refining the
  proxies

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Using the PSP

• Since this is a personal process, you ultimately
  get to choose how to use it
• While rare to find anyone who uses the full
  process (unless part of the organizational
  culture to do so), you can pick and choose which
  parts of this youll take with you

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Personal Commitment

• Like any other change to the way you behave,
  applying the PSP requires commitment to stick
  with it
• Obviously it doesnt help much to use it for two
  months and then quit

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How PSP Helps

• Specific ways the PSP can help include
• Help you make better plans of your activities
• Help you stick to your plan under pressure
• Give you a sound basis for your estimates

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Sharing the PSP

• (This set of slides sounds like proselytizing,
  doesnt it?)
• Its easiest to use the PSP if youre in an
  organization which supports commitment to it
• Doing the PSP solo can be done, but it requires
  lots of discipline (see title of text!)

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Cost of the PSP

• The costs of using the PSP include
• The time to use it
• The cost of maintaining discipline
• Potential risk to your ego when you see whats
  really happening in your work
• Most software engineers think themselves above
  average its sobering if youre not

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Competence

• William Hayes of TI defined four stages of
  competence in doing something, which the PSP
  follows
• Stage 1 is unconscious incompetence, when you
  dont know youre doing poorly
• Stage 2 is conscious incompetence, when you do
  know youre doing poorly

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Competence

• Stage 3 is conscious competence, when you are
  aware of doing reasonably well
• Stage 4 is unconscious competence, when youre
  doing well, and no longer have to think about it
• Thats where we want to be when we no longer
  have to focus on doing well

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PSP Benefits

• Dont forget there are benefits to using the PSP
• Insight into how you work
• Tons of ideas for improving your work
• Having a structure for improving yourself
  professionally
• Achieving control over your work

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PSP Benefits

• Sense of accomplishment from planning and doing
  something
• Improves your ability to contribute to a team
  (because you know yourself well)
• Confidence in a job well done

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PSP Coaching

• Coaching or mentoring is ill-developed in
  software engineering, but the PSP could form the
  foundation for it
• Helping push each other to excellence is a good
  thing

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The Future

• By following a good process, we can
• Understand our strengths and weaknesses,
• Learn from our history, and
• Form a strong foundation from which to try new
  things