Systems Design – 1
scope of design
objectives and constraints
systems design
process design
I/O design
Non-Functional Requirements
Product Design Characteristics
Functional Requirements
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User-friendly
Reliable
Secure
Accessible
Available
Capacity
Throughput
Responsive
Flexible
Scalable
Portable
Configurable
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Maintainable
Well-documented
operational use.
Modular
Extensible
Simple
Efficient
Re-usable
Testable
Conformant
Compatible
Interoperable
Project Constraints
Technical Constraints
Money
Timescale
Skills
legacy systems
programming language
hardware
standards
Organisational constraints
standards
legislation
stakeholders
polotics
quality of requirements
culture
Types of framework that have a dedicated design phase
V model
waterfall
incremental
Input Design
Output Design
User Considerations
User Interface Design
Input and Output Design
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Efficiency
Reliability
Timing .
Accuracy
Usability
Cost
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consistency (consistent look and feel, use of terminology, and so on);
following the logical workflow;
logical tab sequence;
meaningful field descriptions and formats (for example, ‘Enter order date (dd/mm/yyyy)’);
identification of mandatory values;
default values;
confirmation messages;
clear error messages;
progress indicators;
facilities to undo/back out;
context-sensitive help;
alternative data entry mechanisms (such as keyboard shortcuts);
limited entry options (such as drop-down lists and tick boxes);
use of jargon-free language;
simplicity (uncluttered screens, reports with only relevant information, and so on).
Output User-Interfaces
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On demand
Summary
Exception
Data dumps
Archive
system to System Data Interchange
Detailed program specification
high level design
stepwise refinement
bottom down
top up
Programming Constructs
selection
iteration
sequence
coupling cohesion
unit/compenent design
object-oriented design