2.3 Producing Robust Programs Flashcards Preview

GCSE OCR Computer Science > 2.3 Producing Robust Programs > Flashcards

Flashcards in 2.3 Producing Robust Programs Deck (18)
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1
Q

What is a check digit?

A

The last one or two digits in a code are used to check the other digits are correct

E.g. bar code readers in supermarkets use check digits.

2
Q

What is a format check?

A

Checks that the data is the correct format.

E.g. National Insurance Number in the form LL 99 99 99 L where L is any letter and 9 is any number.

3
Q

What is a length check?

A

Checks that the data isn’t too short or too long.

E.g. a password needs to be more than 8 characters.

4
Q

What is a lookup table?

A

Looks up acceptable values in a table.

E.g. there are only 7 possible days of the week.

5
Q

What is a presence check?

A

Checks that data has been entered into a field.

E.g. in most databases, a key field card can’t be left blank.

6
Q

What is a range check?

A

Checks that a value falls within a specific range.

E.g. number of hours worked (h):
0 < h < 50

7
Q

What is a spell check?

A

Looks up words in a dictionary.

E.g. Microsoft Word underlines incorrectly spelled words in red.

8
Q

Define authentication

A

A coding method to check that a user is who they say they are and allowed to accesses the program.

The program checks a huge table and reports back to see if the information matches up, if it does then the access is granted

E.g.biometrics, key cards or email.

9
Q

Define input sanitisation

A

Ensures that the input is correct and contains only the permitted characters letters and symbols.

E.g. Dave not Dav%e so the % would be removed.

10
Q

Define maintainability

A

If a program is to be defensive against attacks, then it has to be maintained and up to date.

Informs the reader of a bug or issues.
Explains the code and its function in more detail.
Stop a line of section of code from executing.

E.g. comments and indentation/spacing.

11
Q

Define misuse

A

Maybe in the form of a brute force attack on the program.

Unauthorised acts with intent to impair the operation of the computer.

12
Q

Define iterative testing

A

Testing the code as you create it.

E.g. line by line or a section at a time.

13
Q

Define final testing

A

Carried out at the end of the program when it has been written.

14
Q

Define syntax errors

A

Mistakes in the formatting (the way in which the code is written).

E.g. SPAG mistakes or unneeded capital letters.

15
Q

Define logic errors

A

A bug in a program that causes it to operate incorrectly, but not to terminate or crash (not as intended).

16
Q

Define validation

A

A check made by a computer to ensure that the data entered is sensible or reasonable and within certain limits and rules.

17
Q

What should you consider in defensive design?

A

When data is entered into a program, it’s important that it’s valid, in order for the program to work correctly.

18
Q

When are runtime errors detected?

A

Errors which may cause program errors or the computer to crash, even if there appears to be nothing wrong with the program.

E.g. running out of memory.