System Analysis and Design

Question 1

What is system analysis?

Answer 1

Research -> analysis -> design -> production -> development and testing -> documentation -> implementation -> evaluation. Cycle repeats.

Question 2

Describe different methods of researching a

situation

Answer 2

Observation
Interviews
Questionnaires
Examination of existing documentation

Question 3

Analysis

Answer 3

• Analysis = understand how system works + identify problems
• Any new system that is created will need to take in the same input data and will have to produce the same outputs.
• Identifying problems (e.g. payroll system):
  + The payroll processes too slowly => workers being paid late
  + Employee timesheets get lost before being processed
• New system requirements and specification are established: what hardware and software is required

Question 4

Designing

Answer 4

• Designing the system inputs: data captured and data input
• Choosing the best data capture and data Input methods for the system: paper forms, barcode/card reader, camera
• Data validation: presence, length, range, type, format check
• Data verification: proof-reading, double-entry
• Designing data and file structures:
  + How often will the data need to be accessed
  + How quickly the data needs to be accessed
  + How large will the data files be
• Designing how data will be processed: batch/real-time/online
• Designing outputs:
  + On-screen reports (information displayed on the monitor)
  + Printed reports (hard-copy to be mailed, filed, etc.)

Question 5

Testing

Answer 5

• A typical test would contain:
  + Details of what is being tested
  + The test data to use
  + What is expected to happen when the test is performed
• Selecting test data:
  + Normal data values: in range
  + Extreme data values: the values are chosen to be at the absolute limits of the normal range.
  + Abnormal data values: out of range
• Tests are done in 2 stages:
  + Before the system is delivered to the customer
  + After the system has been delivered and installed with the customer
• If any failures are found, the systems analyst goes back and does some further research, analysis and design to fix these areas.

Question 6

Documentation

Answer 6

• 2 types: user and technical documentation
• User documentation:
  + How to install the system
  + How to start / stop the system
  + How to use the features of the system
  + Screenshots showing the system in typical use
  + Example inputs and outputs
  + Explanations of any error messages that might be shown
  + A troubleshooting guide
• Technical documentation:
  + Details of data structures (data types, field names, etc.)
  + Details of expected inputs
  + Details of validation checks
  + Details of how data is processed
  + Diagrams showing how data moves through the system
  + Flowcharts describing how the system works

Question 7

Implementation

Answer 7

• 2 types: direct changeover or parallel running
• Direct changeover: old system is stopped completely
  + Advantages: takes minimal time and effort, easier to control
  + Disadvantages: no back up, decreases productivity because it is new => needs training/time
• Parallel running: 2 systems (old and new) run at the same time
  + Advantages: back up, can compare outputs
  + Disadvantages: hard to control => extra time and effort

Question 8

Evaluation

Answer 8

• To see if the new system is efficient, easy to use and appropriate
• To evaluate:
  + check against the requirements specification
  + check users’ responses
• Identify any limitations or problems with the new system => repeat cycle