11) What are 5 common problems in the software development process?
a) poor requirements – if requirements are unclear, incomplete, too general, or not testable, there will be problems.
b) unrealistic schedule – if too much work is crammed in too little time, problems are inevitable.
c) inadequate testing – no one will know whether or not the program is any good until the customer complains or systems crash.
d) featuritis – requests to pile on new features after development is underway; extremely common.
e) miscommunication – if developers don’t know what’s needed or customer’s have erroneous expectations, problems are guaranteed.
12) What are 5 common solutions to software development problems?
solid requirements – clear, complete, detailed, cohesive, attainable, testable requirements that are agreed to by all players. Use prototypes to help nail down requirements.
realistic schedules – allow adequate time for planning, design, testing, bug fixing, re-testing, changes, and documentation; personnel should be able to complete the project without burning out.
Adequate testing – starts testing early on, re-test after fixes or changes, plan for adequate time for testing and bug fixing.
stick to initial requirements as much as possible – be prepared to defend against changes and additions once development has begun, and be prepared to explain consequences. If changes are necessary, they should be adequately reflected in related schedule changes. If possible, use rapid prototyping during the design phase so that customer can see what to expect. This will provide them a higher comfort level with their requirement decisions and minimize changes later on.
Communication – requires walkthroughs and inspections when appropriate; make extensive use of group
Communication tools – e-mail, GroupWare, networked bug-tracking tools and change management tools Intranet capabilities, etc.; insure that documentation is available and up-to-date – preferably electronic, not paper; promote teamwork and cooperation; use protoypes early on so that customers’ expectations are clarified.
13) What is software ‘quality’?
Quality software is reasonably bug-free, delivered on time and within budget, meets requirements and/or expectations, and is maintainable. However, quality is obviously a subjective term. It will depend on who the ‘customer’ is and their overall influence in the scheme of things. A wide-angle view of the ‘customers’ of a software development project might include
end-users, customer acceptance testers, customer contract officers, customer management, the development organization’s management/accountants/testers/salespeople, future software maintenance engineers, stockholders, magazine columnists, etc.Each type of ‘customer’ will have their own slant on ‘quality’ – the accounting department might define quality in terms of profits while an end-user might define quality as user-friendly and bug-free.
14) What is ‘good code’?
‘Good code’ is code that works, is bug free, and is readable and maintainable. Some organizations have coding ‘standards’ that all developers are supposed to adhere to, but everyone has different ideas about what’s best, or what is too many or too few rules. There are also various theories and metrics, such as McCabe Complexity metrics. It should be kept
in mind that excessive use of standards and rules can stifle productivity and creativity. ‘Peer reviews’, ‘buddy checks’ code analysis tools, etc. can be used to check for problems and enforce standards. For C and C++ coding, here are some typical ideas to consider in setting rules/standards; these may or may not apply to a particular situation:
minimize or eliminate use of global variables.
use descriptive function and method names – use both upper and lower case, avoid abbreviations, use as many characters as necessary to be adequately descriptive (use of more than 20 characters is not out of line); be consistent in naming conventions.
use descriptive variable names – use both upper and lower case, avoid abbreviations, use as many characters as necessary to be adequately descriptive (use of more than 20 characters is not out of line); be consistent in naming conventions.
function and method sizes should be minimized; less than 100 lines of code is good, less than 50 lines is preferable.
function descriptions should be clearly spelled out in comments preceding a function’s code.
organize code for readability.
use whitespace generously – vertically and horizontally
each line of code should contain 70 characters max.
one code statement per line.
coding style should be consistent throught a program (eg, use of brackets, indentations, naming conventions, etc.)
in adding comments, err on the side of too many rather than too few comments; a common rule of thumb is that there should be at least as many lines of comments (including header blocks) as lines of code.
no matter how small, an application should include documentaion of the overall program function and flow (even a few paragraphs is better than nothing); or if possible a separate flow chart and detailed program documentation.
make extensive use of error handling procedures and status and error logging.
for C++, to minimize complexity and increase maintainability, avoid too many levels of inheritance in class heirarchies
(relative to the size and complexity of the application). Minimize use of multiple inheritance, and minimize use of operator
overloading (note that the Java programming language eliminates multiple inheritance and operator overloading.)
for C++, keep class methods small, less than 50 lines of code per method is preferable.
for C++, make liberal use of exception handlers
15) What is ‘good design’?
‘Design’ could refer to many things, but often refers to ‘functional design’ or ‘internal design’. Good internal design is indicated by software code whose overall structure is clear, understandable, easily modifiable, and maintainable; is robust with sufficient error-handling and status logging capability; and works correctly when implemented. Good functional design is indicated by an application whose functionality can be traced back to customer and end-user requirements. (See further discussion of functional and internal design in ‘What’s the big deal about requirements?’ in FAQ #2.) For programs that have a user interface, it’s often a good idea to assume that the end user will have little computer knowledge and may not read a user manual or even the on-line help; some common rules-of-thumb include: the program should act in a way that least surprises the user it should always be evident to the user what can be done next and how to exit the program shouldn’t let the users do something stupid without warning them.
16) What is SEI? CMM? ISO? IEEE? ANSI? Will it help?
SEI = ‘Software Engineering Institute’ at Carnegie-Mellon University; initiated by the U.S. Defense Department to help improve software development processes.
CMM = ‘Capability Maturity Model’, developed by the SEI. It’s a model of 5 levels of organizational ‘maturity’ that determine effectiveness in delivering quality software. It is geared to large organizations such as large U.S.
Defense Department contractors. However, many of the QA processes involved are appropriate to any organization, and if reasonably applied can be helpful. Organizations can receive CMM ratings by undergoing assessments by qualified auditors.
Level 1 – characterized by chaos, periodic panics, and heroic
efforts required by individuals to successfully
complete projects. Few if any processes in place;
successes may not be repeatable.
Level 2 – software project tracking, requirements management,
realistic planning, and configuration management
processes are in place; successful practices can
Level 3 – standard software development and maintenance processes
are integrated throughout an organization; a Software
Engineering Process Group is is in place to oversee
software processes, and training programs are used to
ensure understanding and compliance.
Level 4 – metrics are used to track productivity, processes,
and products. Project performance is predictable,
and quality is consistently high.
Level 5 – the focus is on continouous process improvement. The
impact of new processes and technologies can be
predicted and effectively implemented when required.
(Perspective on CMM ratings: During 1992-1996 533 organizations
were assessed. Of those, 62% were rated at Level 1, 23% at 2,
13% at 3, 2% at 4, and 0.4% at 5. The median size of
organizations was 100 software engineering/maintenance personnel;
31% of organizations were U.S. federal contractors. For those
rated at Level 1, the most problematical key process area was
in Software Quality Assurance.)
ISO = ‘International Organization for Standards’ – The ISO 9001, 9002, and 9003 standards concern quality systems that are assessed by outside auditors, and they apply to many kinds of production and manufacturing organizations, not just software. The most comprehensive is 9001, and this is the one most often used by software development organizations. It covers documentation, design, development, production, testing, installation, servicing, and other
processes. ISO 9000-3 (not the same as 9003) is a guideline for applying ISO 9001 to software development organizations. The U.S. version of the ISO 9000 series standards is exactly the same as the international version, and is called the ANSI/ASQ Q9000 series. The U.S. version can be purchased directly from the ASQ (American Society for Quality) or the ANSI organizations. To be ISO 9001 certified, a third-party auditor assesses an organization, and
Certification is typically good for about 3 years, after which a complete reassessment is required. Note that ISO 9000 certification does not necessarily indicate quality products – it indicates only those documented processes are followed.
(Publication of revised ISO standards are expected in late 2000; see http://www.iso.ch/ for latest info.)
IEEE = ‘Institute of Electrical and Electronics Engineers’ – among other things, creates standards such as ‘IEEE Standard for Software Test Documentation’ (IEEE/ANSI Standard 829), ‘IEEE Standard of Software Unit Testing (IEEE/ANSI Standard 1008), ‘IEEE Standard for Software Quality Assurance Plans’ (IEEE/ANSI Standard 730), and others.
ANSI = ‘American National Standards Institute’, the primary industrial standards body in the U.S.; publishes some software-related standards in conjunction with the IEEE and ASQ (American Society for Quality). Other software development process assessment methods besides CMM and ISO 9000 include SPICE, Trillium, TickIT. and Bootstrap.
17) What is the ‘software life cycle’?
The life cycle begins when an application is first conceived and ends when it is no longer in use. It includes aspects such as initial concept, requirements analysis, functional design, internal design, documentation planning, test planning, coding, document preparation, integration, testing, maintenance, updates, retesting, phase-out, and other aspects.