CP1 Computing January 2005

[1](a)

A school secretary makes use of an integrated software package which provides a number of features. Describe each of the following features, giving an example of how the secretary might use the feature in each case:

(i)

mail-merge

[2]

produces a number of similar documents where field values are imported from a database (or spreadsheet)
Example : personalised letters could be produced to inform pupils about exam times.

(ii)

data portability

[2]

data from one program can be transferred to another program.
data from a pupil database such as names could be transferred to a spreadsheet for attendance records.

(b)

Describe one advantage of having a programming facility within the package.

[1]

an application can be customised to the exact needs of the user.

[2](a)

Name two types of programming errors which may occur, giving an example in each case.

[4]

syntax error
Example : PRUNT(PROFIT)
... instead of PRINT(PROFIT)
logical error
Example : PROFIT := INCOME + EXPENSES
... instead of PROFIT := INCOME - EXPENSES

(b)

Explain why the use of self-documenting code in a computer program makes errors easier to discover.

[1]

self-documenting code is more meaningful and easier for a programmer to understand, so it will be easier to find errors. The section causing the error should be easier to identify.

(c)

Explain why the use of standard modules in a computer program helps to avoid errors.

[1]

The subroutines in a standard module have already been tested and therefore should not cause any errors.

[3]

A linear search can be used to find a particular value in a set of ordered values.

(i)

Name an alternative search method which is normally faster than a linear search for a set of ordered values.

[1]

binary search

(ii)

Describe a situation where the search method you named in part (i) cannot be used.

[1]

if the data is not sorted then a binary search cannot be used.

(iii)

Describe a situation where the search method you named in part (i) can be used but where the linear search is probably more suitable.

[1]

a sorted file which has very few records.

[4](a)

Write down an example of data which would best be stored in each of the following data types, giving a different example in each case. State a reason why it is the best data type in each case:

(i)

a real data type;

[2]

an average of pupil's exam marks Eg 78.5
there may be fractions

(ii)

a boolean data type;

[2]

whether a pupil travels to school by bus
only two values - YES or NO.

(iii)

a character data type;

[2]

a pupil's exam grade
possible values only a single character - A, B, C, D, E or U.

(iv)

a string data type.

[2]

a pupil's name
will consist of a number of characters - Eg JOHN SMITH

(b)

A certain computer system allows the addition of an integer data type to a real data type.
What data type would you expect the result of this addition to be?

[1]

the result will be a real

(c)

Draw and label a diagram of a two-dimensional array, using suitable example data.

[2]

a two-dimensional array of pupil exam marks (integers).

	Tom Jones	John Smith	Jane Thomas
Maths	79	82	56
English	67	54	49
Science	68	63	55
ICT	90	87	77

[5](a)

Describe the difference between applications software and systems software.

[2]

applications software - programs that allow the user to perform specific tasks (Eg. a Spreadsheet program)
systems software - programs that help run the computer system (Eg a program that formats a disc)

(b)

What is the name of a program which converts a source program into a form that is executable by the computer?

[1]

a translation program such as a compiler.

(c)

Explain what is meant by the term parameter in a computer program.

[1]

a value that is passed to a subroutine.

[6]

A taxi firm uses a paper-based system to handle bookings for taxis. The firm employs a systems analyst to produce a new computer-based system to deal with such bookings.

(i)

In each case describe in detail how the following might be carried out:

(I) requirements analysis;

[2]

interview the management of the firm to find out what tasks they require the new system to perform.
..or ask them to fill in questionnaires.

(II) changeover.

[2]

ending the current system and starting the new system may be done by direct changeover where the old system stops at the same time as the new system starts...
...or by parallel running (running both for a time), phased changeover (gradually introducing the new system) or by piloting (starting the new system with some departments of the firm)

(ii)

Describe two types of documentation which should be produced.

[2]

user documentation - instructions for the user how to install and operate the system.
maintenance documentation - for programmers to be able to understand the system well enough to make changes.

(iii)

Some errors are found in the new system after it has been implemented. Name the type of maintenance which would be required to remove the errors.

[1]

corrective maintenance

(iv)

Why might adaptive maintenance also be necessary for the new system?

[1]

the firm may change (open new branches, buy more cars etc) and the system may need to be changed as well.

[7]

Some programming languages are used for scientific applications, while others are used for commercial applications.

(i)

Describe one feature which it would be useful to have in a language used in a scientific application.

[1]

mathematical functions such as trigonometric functions which can be used in calculations.

(ii)

Describe one feature which it would be useful to have in a language used in a commercial application.

filing functions which can store and retrieve records of data in files.

[8]

Teifi Books sells books via the Internet. When a customer has bought a large number of books from Teifi, or a small number of more expensive books, they are awarded a bonus voucher which they are able to use to save money off a future purchase.

The algorithm used is shown below:

Statement
1	input NumberBooksBought
2	input TotalValueBooksBought
3	if ((NumberBooksBought>10) OR ((NumberBooksBought>5) AND (TotalValueBooksBought > 50)))
4	then output "Award bonus"
5	else output "Do not award bonus"

(i)

State what the output will be for a customer who has bought:

(I) four books of total value £80

[1]

Do not award bonus

(II) six books of total value £60

[1]

Award bonus

(III) twelve books of total value £40

[1]

Award bonus

(ii)

Teifi decides to change its bonus scheme and alters the algorithm so that statement 3 reads:

Statement
3	if ((NumberBooksBought>10) OR ((NumberBooksBought>5) AND (TotalValueBooksBought>50)) OR (TotalValueBooksBought>100))

(I) Give an example of input data which will now give a different result from the original algorithm.

[1]

three books of total value £120
(any number of books less than 5 with total value more than £100)

(II) Suggest why Teifi might have decided to make this change.

[1]

to reward those who have bought just a few of the very expensive books.

[9]

A school student is doing some research for a project and needs to borrow various library books. The student can check the school library catalogue electronically to see if the book is available. If this is not the case, the student can ask the library staff to check if the book is available at a local university library. If it is available there, a member of the school library staff can request to borrow it from the university on the student's behalf. This situation is as shown in the following data flow diagram:

(i)

Describe why this type of diagram is useful in helping to explain a computer system to a non-expert.

[1]

diagrams showing the flow of data are easier to understand than text and there is no need for complicated jargon.

(ii)

Draw the shape used in the diagram to represent an external entity.

[1]

(a shadowed box like the Student box in the diagram)

(iii)

What type of object does the rounded box in the diagram represent?

[1]

a process

(iv)

Give a suitable name for the object shown as a in the diagram.

[1]

request for book

(v)

Give a suitable name for the object shown as b in the diagram.

[1]

university library availability

(vi)

Give a suitable name for the object shown as c in the diagram.

[1]

book details

[10]

In the following question, additional credit (up to 3 marks) will be given if your answer demonstrates skill in written communication.

A commonly used package has a human-computer interface (HCI) which has been carefully designed for a wide range of users.

Explain why the design of the HCI is so important, and what features you would expect to find in a well-designed HCI. You should also describe features which would be particularly helpful to a beginner and those which would be particularly helpful to an expert user.

[7+3]

The design of an HCI is important because it allows users to operate the programs. If an HCI is too difficult to understand or is not easy to use, then the users will either be unable to use the programs or may be put off from trying.

A well-designed HCI will have clear, easy-to-understand ways of opening and running different parts of the package. Simple instructions, possibly in 'Help' documents should be included. There should be a consistent use of features across the different parts of the package so that learning to use them is easier.

Beginners will need a Graphical User Interface (GUI) with clear and understandable icons. These are small pictures representing applications or commands. A mouse pointer is used to select options by clicking on the icons. For example a button with a picture of a printer on may be clicked on to print a document, or a dustbin may be used to delete documents that are dragged into it.

Expert users may be able to type in instructions, possibly involving a number of options to customise the instructions. A hierarchy of menus may also be used where the user navigates through the menus and selects options by clicking on them.