• The design translates the system
requirements into ways of operate them.
• The design is a solution, a “ how to “
approach, compared to analysis, a “what is”
• The design phase focuses on the detailed
implementation of the system recommended
in the feasibility study.
• One way to plan a new system is to focus on
each functional subsystem as a separate
entity or application area.
• Using such an approach, each application area
is treated as if it were totally independent.
• The modular systems approach divides each
application area into a number of smaller
units called modules.
• speed up the systems process.
• eliminates unnecessary duplication.
• result in higher quality.
• provides better control over the total system
• allows flexibility as additional features may be
• parts of the system can be tested separately.
• Numerous unique application requirements
which must be incorporated in common
modules. If a single module is to
accommodate all situations, it will become
very large & complex.
• Modular systems design is best viewed as one
aspect of a broader planning issue, but it is
not a required step in the design process.
• changes and errors affect common modules,
the negative consequences can be
• Inaccurate input data are the most common
cause of error in data processing.
• Errors entered by operator can be controlled
by input design.
• Input design is the process of converting user-
originated inputs to a computer based format.
Goal of input design
• The goal of designing input data is to make
• Error free.
Input media and devices
• Touch Screen
• Point-of-sale terminals
• Sound and speech
• Automatic data capture
• Optical mark recognition (OMR)
• Bar codes
• Optical character recognition (OCR)
• Magnetic Ink
• Electromagnetic transmission
• Smart cards
Data input methods
• ON-LINE - User directly Enters data using
• OFF-LINE -Forms filled by users- for example-
candidates for admission to a college fill forms
OFF LINE DATA ENTRY –
• It is not always possible for the form to give
message when input is wrong, error may be
found after elapse of time period. Therefore,
good controls of automatically detect and if
possible correct errors is required.
ON LINE DATA ENTRY –
1. Errors in on-line data entry due to poor
screen design. System should inform the user
immediately when wrong data is input.
2.Errors in off-line data entry due to bad form
design and human errors by users and data