Defining and Understanding the Problem Flashcards
What do we do in Defining the Problem
The problem itself is to be defined and precisely understood
What are some questions to help define and identify problems
what are the client’s needs which will be met by this product?
Compatibility issues with other existing software and hardware?
Possible performance issues, particularly for internet and graphics (or video)
what are the boundaries of the new system
what is a need
a need is an instance in which some necessity or want exists.
What is a systems analyst
a professional who analyses systems, determines requirements and designs new information systems.
What are some tools or techniques that are used for analysis
Surveys
interviews
Time managment studies
Business analysis
what are requirements
Features, properties or behaviours a system must have to achieve its purpose. Each requirement must be verifiable
what are some common compatibility issues
Problems with different versions of the intended operating systems
COTS products which experience issues when the underlying application is updated.
Not all graphics card are supported by many graphics code libraries
Screens which do not resize to support different screen resolutions
Labels for screen elements which overlap or are no longer aligned correctly when fonts are enlarged
Loss of server connection causes fatal errors over wireless networks
Browsers which do not correctly implement HTML standards set by the W3C (World Wide Web consortium)
what are two common examples of performance issues
The computer appears to be not responding after some function has been initiated (in fact it is busy processing a time consuming task)
Users experience poor response times.
What are boundaries
They define the limits of the problem or system to be developed.
What are some issues relevant to a proposed solution
Points from client’s perspective
Will the existing system be able to perform the required tasks in the foreseeable future
Will the proposed new system meet future needs?
have existing similar solutions been examined?
how crucial is the new system to the total organisation?
Points from the solftware developer’s perspective
What expertise is required to complete this project
What resources are required to develop this project
Will we be able to support this product in the future?
Can we retain/redistribute existing staff and resources to this project?
what are some social and ethical issues that need to be considered
Changing nature of work for users
Effects on level of employment
Effects on the public
what are some areas of cost that should be considered
Development hardware costs?
Development software costs?
Development personnel costs?
Outsourcing costs?
what are some factors to consider when formulating a budget
The available capital
the predicted sales for the finished product
cost savings as a result of the product’s implementation
Predicted future upgrade and maintenance costs for the product
Ongoing customer support costs
Other costs
what are the design specifications from the Developer’s perspective
Data types
Data structures
Algorithms
Variables
Software design approach
Quality assurance
modelling the system
documentation
what are the design specifications from the User’s perspective
interface design
Appropriate messages
Appropriate icons
Relevant data formats for display
Ergonomic issues
Relevance to the user’s environment and computer configuration
Social and ethical issues
what are the system modelling tools used to model a system
System flowcharts
Context diagrams
Data flow diagrams (DFDs)
Structure charts
IPO diagrams
Data dictionaries
Screen Designs (and concept prototypes0
Storyboards
What are some ways for the developer to communicate with users
Meetings
Questionnaires
Memos
interviews
Phone calls and Emails
Concept prototypes
What other documentation are produced during the development process
Algorithims represented using psuedoce or flowcharts
Test data together with expected outputs
Source code inlcuding internal comments and intrinsic doccumenation
What are System flowcharts
They are flowcharts that are used to describe the logic and flow of data through a system. They describe the interactions that can occur between input, processing, output and storage as well as the nature of these components.
What are context diagrams
Context diagrams represent the entire system as a single process. They do not attempt to describe the processes within the system but rather identify the data entering and the information leaving the system together with its source and its destinations (sink). Sources and sinks are known as External entities
What do the symbols in a Context diagram represent
Arrows: are the flow of inputs and outputs
Squares/rectangle: are the external entities
Circle: represent the entire system
What do Data Flow Diagrams represent
The path the data takes through a system. It describes the flow of data and the processes.
What do the symbols on the Data Flow Diagrams represent
Squaure/rectangle: External Entity
Circle: Process
Data Flow: arrow
Data store: open rectangle
What is a valid process in a data flow diagram
A process must have one output and one input
It must Change the data
It should start with a verb
What is a Structure Chart
They are used to model the hierarchy of the subroutines (processes) within a system, together with the sequence in which these subroutines are executed.
What is a call
Causing the execution of a subroutine (process) from within another subroutine
What is control
the influence that causes tasks to execute in their correct sequence
what are the symbols used in a structure chart
Decision: Diamond
Repetition: a circular arrow around the call line
parameter: a circle at the end of an arrow filled (white filled)
Control parameter (flag): a circle at the end of an arrow filled black
call line: just a line
Module or subroutine(process): rectange/square
How to read structure charts
they are read from top to bottom and from the left module to the right.
what is a flag
data items used to indicate that a certain criteria has been met.
what are IPO diagrams
Input process Output diagrams (IPO for short) describe the data entering a process, the nature of the processing performed on the data and the resulting informaiton leaving the process. They are used to further expan on the lower-level processed described on data flow diagrams and structure charts.
What is a Scope
The extent to which a variable is avaliable for use. Global variables are for use by all subroutines in a program where as local variables are available only within the individual subroutine.
What is a data dictionary
It is a carefully documented dictionary that contains all of the variable names and identifiers in a system. It contains all of the identifiers that have been used, data type, storage size, display size and format, scope of usage and various other details.
What are the columns in a Data dicitonary
Identifier: name or data item
Data type: integer, string, floating point or boolean
Format: refers to the display formate where this is applicable example XXNNN
Number of bytes required for storage: stringes will use a single byte if ASCII is used, but two if Unicode is used.
Size for display: the number of characters required to display the contents of the variable on a screen or on paper.
Description: a brief outline of the logical role the data plays within the subroutine
Example: provide a type example of the actual data in its display format
Validation: Refers to the range of allowable values
Scope: is the vairable local or global (only include the global variables)
how to write a array data type in a data dictionary
Array(data type)
how to define a record in a data dictionary
Create a heading row that has the name of the record, then underneath them create rows for each field within the record
what are Screen designs
they provide the interface between user and the software.
What to consider when making a screen design
placement of items
consistency of design
order
grouping and nature of screen elements
use of colour
graphics and fonts
language
what is a storyboard
it describes the screens used in a system together with how each screen interacts with other screens.
what is Software Quality
The extent to which desirable features are incorporated in to software so it can reliably and efficiently continue to meet the needs of users.
