5. The system Life Cycle Flashcards
what is a system life cycle?
a structured process that guides the planning, creation, testing, and deployment of an information system
what does a system life cycle do?
Ensures systems are systematically developed, meeting needs of stakeholders, minimising risks and maximising efficiency
what’s the first stage and what’s its purpose?
analysis, Gather detailed requirements from stakeholders and analyse them to understand what the system should accomplish
what are research methods?
helps to analyse the current IT system in order to help understand the state of the current system
identify areas for improvement
what are the 4 research methods?
observations, interviews, questionnaires, existing documents
what is an observation?
Watching users interact with the current system to see how it acts/works
adv of observation
Reliable data
Inexpensive
Good for getting an overall picture of existing system
dis of observation?
People don’t always behave in the same way under observation
adv of questionnaire?
Quick
Inexpensive
Can be anonymous
dis of questionnaire
Can’t ask follow up questions
Low response rate
Answers might be vague
adv of interviews
Can monitor body language and facial queues
Gives employees an opportunity to
dis of interviews
Time consuming
Cannot remain anonymous
Employees may be uncomfortable and not give honest responses in fear of repercussions
adv of esixting docs?
Obtain information that can’t be obtained from other methods
dis of existing docs
Time consuming which can be costly
how to analyze the current system?
Inputs
Outputs
Processing
Problems
User requirements
Information requirements
what is drawn up from the results of the analysis
requirements specification
what’s the second stage and what is its purpose?
design
Develop architectural blueprints for the system, including database design, user interfaces, and system interfaces.
What are file/data structures?
Field names
Filed lengths
Data types
Primary keys
what’s a file?
A file consists of records and records are made up of fields
Each record is identified by its unique primary key field
what are different data types?
alphanumerical: combination of characters (letters or text) and numeric data
character:A single letter/symbol
text: Stores a combination of characters (letters, text, symbols, special characters etc.) and numeric data
boolean: Stores data in a Yes/No or True/False
numeric: Integers, Decimals,Currency
Date/Time
What are validation routines?
checks placed on data being entered to ensure it matches the design of the system
prevent errors and maintain data integrity
what is range check?
Ensures the data entered as a number falls within a particular range
For children aged between 5 and 10, checks to make sure numbers <5 and >10 are not accepted
what’s length check
Checks the length of a string
Password must be a minimum of 8 characters, checks to make sure the length is >=8
what’s type check
Check the data type of a field
Enter distance in whole miles, checks to make sure decimals are not accepted
whats format check
Ensures that the data has been entered in the correct format
Enter date of birth (DD/MM/YY), check to make sure the format is correct
what’s presence check
Looks to see if any data has been entered in a field
Enter your username ,check to make sure the filed has not been left blank
whats check digit
Check digits are numerical values that are the final digit of a larger code
Barcodes
What are input and output formats?
What are input and output formats?
examples of input formats
Having a user-friendly layout
Providing clear instructions
Using appropriate question types -
Using validation routines
examples of output formats
Screen layouts:
Report layouts:
Readability, visual appeal, and efficient use of space
what’s the third stage and whats the purpose?
verify that the system meets all requirements, functions correctly, and is free of bugs through various testing methods.
what are test designs
1.a method of testing a completed system to ensure all parts work as intended
2.Each module needs to be tested independently
3.Testing is done again once all modules are joined together
- The results of testing may indicate changes need to be made, testing is repeated once all changes have been made
test design- data structures
Test all data is stored correctly
test design- file structures
Test all data is stored in the correct format
test designs- input formats
test that data can be entered correctly
test designs- output formats
Tests that screen output and reports are in the correct format
test designs- Validation routines
Tests that the system rejects unreasonable data being inputted
what are test plans and what does it consist of?
Test data: specific data used for testing purposes
Expected outcomes: predicted results based on test data
Actual outcomes: results obtained from testing
Remedial action: steps taken to fix identified issues
What is test data?
specific data used for testing purposes
what are the 4 categories of test datas?
Normal
Extreme
Abnormal
Live
what is normal data
data that should be accepted in the system
has a known outcome
what is extreme data
data that is on the limits of what is acceptable
what is abnormal data
outside of the limits of what is acceptable
should be rejected by the system
what is live data
data from the old system used on the new system
has known outcomes, so it can be compared to the new system to ensure the new system works
what’s the fourth stage and its purpose?
implementation
Deploy the system to the production environment and ensure all components work together in the live setting.
system implementation?
a process that happens after a system has been fully tested and is working correctly
how does implementation occur?
Data is transferred from old to new system
then system changeover
what’s a changeover
changeover is moving from the old system to the new system
what are the 4 ways a changeover can happen
Direct
Parallel
Pilot running
Phased
what is direct changeover
The old system is replaced by the new system immediately
Used when quick implementation is necessary
what is parallel running
Both old and new systems run simultaneously for a period before the old system is phased out
Used when a smooth transition with minimal risk is required
what is pilot running
The new system is implemented in a small, controlled environment before full-scale implementation
Used when testing the new system in a real-world setting
what is phased implementation
The new system is implemented in stages, with each stage replacing a part of the old system
Used when a gradual transition is preferred to minimise disruption
adv of direct changeover
Fast implementation
Cost-effective as only one system is in operation
dis of direct changeover
High risk of failure
No fallback
Users can’t be trained on the new system
No backup of the system
adv of parallel running
Lower risk
Easy comparison of systems
dis of parallel running
Time-consuming
Resource-intensive
adv of pilot running
Low risk as only trialled in one department/centre/branch
Allows for fine-tuning
Staff have time to train with the new system
Few errors as it’s fully tested
dis of pilot running
Slower implementation
Potential inconsistencies
Confusion as there are 2 systems in use
No backup for the department/centre/branch using the new system
adv of phased implementation
Reduced risk
Easier to manage
dis of phased implementation
Takes longer
Potential compatibility issues
what is technical documentation?
detailed information on the system’s inner workings and programming for developers and IT staff
what does technical documentation enables the system to be?
Maintained
Repaired
Updated
Technical documentation includes:
Purpose of the system/program
Limitations
Program listing
Program language
Program flowcharts/algorithms
System flowcharts
Hardware & software requirements
File structures
List of variables
Input format
Output format
Sample runs/test runs
Validation routines
what is user documentation?
instructions and guidance for end-users on how to operate the system
enables end-users to effectively use the system and overcome problems
User documentation includes:
Purpose of the system
Limitations
Hardware & software requirements
Loading/running/installing software
Saving files
Printing data
Adding records
Deleting/editing records
Input format
Output format
Sample runs
Error messages
Error handling
Troubleshooting guide/helpline
Frequently asked questions
Glossary of terms
what must you assess in order to evaluate a system?
The efficiency of the solution
The ease of use of the solution
The appropriateness of the solution
what benefits do you get from evaluating a system?
identify limitations and propose improvements
how to evaluate a system’s performance?
Resource usage
Time
Cost
how to evaluate the ease of use?
1.user-friendly
2. accessible the solution is for its intended audience
3. system is easy to learn and use, 4. users can accomplish their tasks without difficulty
how to evaluate the efficiency of the solution?
- is the system is operating optimally or if improvements could be made to its efficiency
- areas that may be consuming excessive resources or time,
how to evaluate the appropriateness of the solution?
- Compare the implemented solution with the original task requirements.
- evaluate how well it meets the intended purpose
3.Outline the initial objectives of the system and discuss how the solution addresses each one - Highlight requirements that haven’t been fully met and discuss possible reasons for this
- Collect users’ responses to the results of testing the system
- identify limitations and propose improvements
