Software <3 Flashcards
What is the analysis stage of software development?
The stage where an initial description of the problem to be solved is examined and turned into a precise description of exactly what the software will be able to do.
What must the Systems Analyst be able to do?
Communicate effectively with the client in order to discover exactly what problem is that they want to solve
Communicate with the development team in order to accurately describe what needs to be produced.
Why is the analysis stage of software development important?
The initial problem description has to be clearly stated and the software specification agreed upon
Or subsequent stages will suffer from delays and difficulties due to the need to re-analyse the task and rewrite the software specification.
The Systems Analyst will create a software specification at the end of the Analysis stage of software development. What is a software specification?
The software specification describes what the software to be created must be able to do.
What is the design stage of software development?
When the software specification created by the systems analyst is turned into a design which can be used by the team of programmers to write the code.
The more time spent on this stage, the less time will be needed to be spent on the next one.
What is Top Down Design?
Any software problem can be broken down into smaller more easily managed problems.
These problems can subsequently be further broken down into a set of simple steps.
Advantages of Modular Design?
- Modules can be tested independently.
- A well written module may be able to be re-used in another application.
- Modules can mirror the structure of the data being processed by the application.
What is Stepwise refinement?
The process of designing the logic of each module.
This involves breaking the module down into successively smaller steps, eventually resulting in a set of pseudocode instructions which can be converted into the chosen programming language.
What is the the implementation stage?
(If the design has been written in enough detail)
The implementation stage should just be a matter of using the design to create the source code for the application.
Testing a piece of software has several purposes.What should it check?
- The software meets the specification
- It is robust
- It is reliable
What does testing do?
Testing can only demonstrate the presence of errors, it cannot demonstrate their absence.
What 2 things should testing be?
Systematic, which means testing in a logical order
Comprehensive which means testing every possible scenario.
What is the documentation stage?
When the guides to using and installing the software are produced.
what should the user guide for the software should include?
A comprehensive guide to the menu options, and how each one functions.
what is the evaluation stage?
Where the software is critically examined by both the client and the developer.
What do we evaluate for?
- Robustness
- Maintainability
- Efficiency
- Usability
What are the three types of software maintenance?
- Corrective
- Adaptive
- Perfective
What is corrective maintenance
Fixing errors that were not detected during testing but which occur during actual use of the program.
The developer will be responsible for any costs incurred by this type of maintenance.
What is adaptive maintenance?
Fixing issues caused by when the program’s environment changes.
The cost is usually borne by the client but there may be negotiation depending upon how predictable the change in circumstances was.
What is perfective maintenance?
When the client requests changes or improvements to the program which were not in the original software specification.
The cost of perfective maintenance is likely to be borne by the client.
What is agile software development?
Breaks a project down into a series of short development goals, often called sprints
What does agile software development focus on?
It focuses on small scale developments, and with teams of people who have a flexible approach to changes in requirements.
What are the benefits of the Agile method?
- The client is involved throughout the process, giving constant feedback on prototypes of the software during development.
- Collaboration within teams of developers throughout the process.
- Reduced development time.
- Increased responsiveness to changing circumstances.
- More reduced costs due to the efficiency of using small groups of developers.
What are the STRENGTHS of Iterative Methodology (traditional)?
- Rigid planning structure
- Good for large teams
- Helps to plan and track large software projects
- Clear agreement on outcomes at start of project
What are the STRENGTHS of Agile Methodology?
- Copes well with little cumulative changes as the project progresses.
- Good for small-scale projects like most Apps
- Ongoing involvement of client allows changes to be agreed quickly
- Changes cause less delay or can be tackled in the next version.
What are the WEAKNESSES of Iterative Methodology (traditional)?
- Very rigid approach does not deal well with mid-project changes
- Can over-complicate simple projects
- Unidentified issues at the analysis stage can be time-consuming and costly to fix
- Little involvement of client after analysis.
What are the WEAKNESSES of Agile Methodology?
]-Works best with small teams
- Needs close version control and tracking of changes
- Can be difficult to determine the full scope of the project in the early stages
- Usually no legally binding agreement at the start
As part of the software specification, what are the four areas are analysed and agreed upon?
- The overall purpose
- The scope
- Boundaries
- Functional requirements.
What is the purpose of a program?
General statement about what the program is required to do. It should clarify the main point(s) of the program between the developers and clients
What does the scope clarify?
What the project must cover, often written as a list of deliverables.
What does the boundaries clarify?
What the project will not cover.
What should a software specification do?
It describes what a program must do
What is top down analysis?
This allows the developers to break this complex problem description into a series of smaller sub-problem descriptions.
What does data flow show?
The movements of items of data into and out of each part of the program.
What is an integer?
A negative or positive number including zero with no decimal point
What is a real number?
A negative or positive number including zero with a decimal point
What is a boolean?
A value which can be either true or false
What is an array?
A structured data type storing values of the same type
What do simple data types include?
- INTEGER
- REAL
- CHARACTER
- BOOLEAN
What do structured data types include:
- ARRAY
- STRING
- RECORD
How are integers stored?
Using two’s complement notation
How are real numbers stored?
Using floating point notation which uses an exponent and a mantissa
How are characters stored?
As Extended ASCII codes (8 bit / 256 character set) or if more than 256 are needed then they are stored using Unicode
How are booleans stored?
Using 1 bit - as on or off
What is a record?
Contain variables of different types
Allows us to keep related items of data about a person or thing together, which is more logical than tying things together in multiple parallel arrays.
What is an algorithm?
A detailed sequence of steps which, when followed, will accomplish a task
What is an index?
A position in an array
What is a standard algorithm?
Certain algorithms that appear in program after program
What is input validation?
Making sure that the data input by the user is acceptable
What is the linear search algorithm?
Used to find an item in a list
What does counting occurrences do?
Sets a total to zero at the beginning and increments it as items are found to match the search item
How do you find the maximum/minimum
Sets an initial value to the first item in the array then compares it to the remaining items
What is a computational construct?
Features of a high level language which have been designed to make this task easier.
A computational construct is a system of data representation and control structures used to solve problems using a computer through a programming language.
What are the three control structures?
Sequence, selection and iteration
What is variable declaration?
When a variable is created in a program
What is a local variable?
One which only exists within the sub-program where it is being used.
What is a global variable?
Has a wider scope - it exists and can be altered throughout the entire program.
This means that if its value is changed inside a sub-program, that value will remain changed and will affect its value wherever in the program it is used, possibly unintentionally
What is modulus division?
A type of division where two integer numbers are divided and the remainder is returned.
What does asc(char) do?
returns the ASCII code of a character
What does char(char) do?
returns the character from an ASCII code
What are sub-programs?
Named blocks of code which can be run from within another part of the program.
For instance, an input validation sub-program may be called several times asking for different inputs.
This makes your program easier to understand and makes writing code more efficient
What is a method?
An object oriented language is a function that is defined inside a class.
What are CSV files?
Comma-Separated Value files are a standard file format for exchanging organised data between programs such as databases and spreadsheets.
As implied by the name, they are simply text files with each data item (similar to a field in a database) separated by a comma value, and each row (record) separated by a line break.
What is a computational construct?
A combination of control structures which can be used to make solving programming problems easier
What is internal commentary?
Short statements embedded in the source code describing how that part of the program functions in order to aid code readability
What is systematic testing
Where tests are done in a way which is planned, and which can be documented as a result.
The testing results are documented, in a clear list matching test data with results, so that time is not wasted repeating work done already, and the developers know exactly what has and hasn’t been tested.
What is comprehensive testing?
When every aspect and functional requirement of the software is tested.
What is beta testing?
When you test it in the environment which it has been designed for
Why is Beta testing important?
- It is essential that the client is able to test the software and make sure that it meets the specification they agreed to at the analysis stage
- Although the programming team will have tested the software with appropriate test data, it is can be difficult for the programming team to test their work as a user who might make unpredictable mistakes rather than as a developer who is very familiar with the application they have been building
- It is important that the people who are actually going to use the software are able to test it
What is a test plan?
A set of test data which is created in order to systematically and comprehensively test the software which the client has requested in order to ensure that it meets the original specification when delivered.
A test plan will include:
- The software specification against which the results of the tests will be evaluated
- A schedule for the testing process
- Details of what is and what is not to be tested
- The test data and the expected results
- Documentation of the testing process
What is debugging?
The process of finding and correcting errors in code.
What is a dry run?
Simply a manual run-through the pseudocode or source code of the program
What is fitness for purpose?
Making sure that the program meets all the requirements that were agreed in the software specification drawn up during the analysis of the problem, or meets the clients’ needs if using an agile methodology
What is an execution error?
an execution (or run-time) error is one which causes the program to stop (crash) when it is run
What is efficient programs?
Make sensible use of coding constructs that run with the least amount of code required to be executed
