Year 11 Computing Short Notes – Last updated on 1st December 2022
Data Inputting
- Three types of data inputting; manually, using form and scanning.
- Three possible types of errors
- Data entry errors
• Omission error – Something is left out. Ex: _ello instead of hello
• Substitution error – Something is replacing in error Ex: nello instead
of hello
• Transposition error – Two things are replaced in error Ex: holle
instead of hello
Verification and Validation
• Verification to be done after inputting
o Visual checking -> Manually check the data is correct
o Double entry -> Data is entered twice (Eg: passwords on
signup)
• Validation to be done before inputting
o Range check -> Sets minima and maxima for entered data
o Type check -> Check that the type of data is correct (int,
String)
o Presence check -> Checks that data is actually entered
o Length check -> Checks that data is of a particular length
o Picture check -> Check that format of data is correct
o Consistency -> Checks that data corresponds between
specific fields
o Control data -> Verify the actual amounts of input is as
should be
o Check digit verification -> Numerical input with a sum being
worked on with the answer validating the input
- Hardware errors
Power cuts
• Prevention via UPS
Hardware corruption
• Prevention via on-site backups
- Programming errors
Syntax errors
• Ex: Forgetting to close curly brackets, forgetting semicolon
• Prevention via translator debugger
Logic error
• Ex: Syntax is correct but programming logic to achieve goal is wrong
• Dry run and trace facilities1
Runtime error
• Ex: Using a 6th position in a 5 letter array, dividing by zero
• Dry run and trace facilities
1
,Year 11 Computing Short Notes – Last updated on 1st December 2022
1
Programs that indicated the exact path taken by the computer during the execution
2
, Year 11 Computing Short Notes – Last updated on 1st December 2022
Modulo 11
How to perform module 11 calculations?
1. Assign weights:
2. Find the multiple of the digits with their weight
3. Add the answer to each other, which makes 117 in the case above.
4. Divide the answer by 11 and save the remainder. = 10 R 4
5. 4 will be the check digit
How to validated modulo 11 check digit
1. Assign weights with check digit on last digit
2. Find the multiple of the digits with their weight
3. Add the answer to each other, which makes 121
4. Divide the answer by 11 and save the remainder. = 11 R 0
5. If the remainder is 0, everything is validated.
Documentation
There are three types of documentation, which together form System Documentation
- Operator’s manual – Used to help people perform maintenance on the source code
(Technical)
- Messages which prompt specific inputs and outputs
- Explanation of error messages
- Various peripherals
- User’s manual – Used to assist front-end users make use of the program
(Non-technical)
- Examples via screenshots
- Clarification of error messages
- Explanation of the normal running of the program
- Programming Documentation – Used to explain how the program works to a non-author
program (Technical)
- Description of the Problem
- A listing of all programs included
- Flowcharts
3
Data Inputting
- Three types of data inputting; manually, using form and scanning.
- Three possible types of errors
- Data entry errors
• Omission error – Something is left out. Ex: _ello instead of hello
• Substitution error – Something is replacing in error Ex: nello instead
of hello
• Transposition error – Two things are replaced in error Ex: holle
instead of hello
Verification and Validation
• Verification to be done after inputting
o Visual checking -> Manually check the data is correct
o Double entry -> Data is entered twice (Eg: passwords on
signup)
• Validation to be done before inputting
o Range check -> Sets minima and maxima for entered data
o Type check -> Check that the type of data is correct (int,
String)
o Presence check -> Checks that data is actually entered
o Length check -> Checks that data is of a particular length
o Picture check -> Check that format of data is correct
o Consistency -> Checks that data corresponds between
specific fields
o Control data -> Verify the actual amounts of input is as
should be
o Check digit verification -> Numerical input with a sum being
worked on with the answer validating the input
- Hardware errors
Power cuts
• Prevention via UPS
Hardware corruption
• Prevention via on-site backups
- Programming errors
Syntax errors
• Ex: Forgetting to close curly brackets, forgetting semicolon
• Prevention via translator debugger
Logic error
• Ex: Syntax is correct but programming logic to achieve goal is wrong
• Dry run and trace facilities1
Runtime error
• Ex: Using a 6th position in a 5 letter array, dividing by zero
• Dry run and trace facilities
1
,Year 11 Computing Short Notes – Last updated on 1st December 2022
1
Programs that indicated the exact path taken by the computer during the execution
2
, Year 11 Computing Short Notes – Last updated on 1st December 2022
Modulo 11
How to perform module 11 calculations?
1. Assign weights:
2. Find the multiple of the digits with their weight
3. Add the answer to each other, which makes 117 in the case above.
4. Divide the answer by 11 and save the remainder. = 10 R 4
5. 4 will be the check digit
How to validated modulo 11 check digit
1. Assign weights with check digit on last digit
2. Find the multiple of the digits with their weight
3. Add the answer to each other, which makes 121
4. Divide the answer by 11 and save the remainder. = 11 R 0
5. If the remainder is 0, everything is validated.
Documentation
There are three types of documentation, which together form System Documentation
- Operator’s manual – Used to help people perform maintenance on the source code
(Technical)
- Messages which prompt specific inputs and outputs
- Explanation of error messages
- Various peripherals
- User’s manual – Used to assist front-end users make use of the program
(Non-technical)
- Examples via screenshots
- Clarification of error messages
- Explanation of the normal running of the program
- Programming Documentation – Used to explain how the program works to a non-author
program (Technical)
- Description of the Problem
- A listing of all programs included
- Flowcharts
3
