CP1 Computing Jan 2006

[1]

Information about the employees of a company is held in a computer system.

(i)

Describe employee data which would best be stored in each of the following data types:

integer data type;

[1]

Year of joining the company - Eg. 2006

real data type;

[1]

Monthly salary - Eg. 125.50

boolean data type;

[1]

Married (Yes or No)

string data type;

[1]

Employee's name - Eg. Thomas Jones

(ii)

Describe employee data which could be conveniently stored in a record, but which could not be stored in a two-dimensional array.

[1]

The employee's Name, Date of Birth and Monthly Pay Rate.

Explain why the data could not be stored in a two-dimensional array.

[1]

The data are of differing data types (string, date and real).

[2]

A programmer is required to do some maintenance on an existing computer program.

(i)

What term is used for the information produced by the original programmer to help maintain the program?

[1]

documentation

(ii)

The program requires amending so that it will run on a different operating system. What is the name for this type of maintenance?

[1]

adaptive maintenance

(iii)

Name and describe two other types of program maintenance.

[4]

corrective maintenance - correcting any bugs that may arise in the program.
perfective maintenance - improving the performance of the program.

[3](a)

Describe two features which would be useful in a programming language designed to produce web pages.

[2]

hyperlinks - to navigate from one page to another.
embedding of pictures, videos, sounds in a web page.

(b)

Another programming language has very good record-handling and file-handling facilities. What type of application might this language be useful for?

[1]

commercial applications for businesses.

(c)

Describe the difference between systems software and applications software.

[2]

systems software - programs that help in the running of the system. Eg. A program that copies a file from one folder to another.
applications software - programs that perform specific tasks Eg. a word processing program.

[4]

The following program extract is intended to output the maximum of a set of three numbers.
The extract contains two different types of program error.
In each case, write down the statement number, name the type of error and write down the corrected statement.

[4]

Statement
1	input Number1
2	input Number2
3	input Number3
4	MaxNumber = Number1
5	if Number2 > MaxNumber thne MaxNumber = Number2
6	if Number3 > MaxNumber then MaxNumber = Number2
7	output MaxNumber

Error type 1 :

statement number 5
syntax error
if Number2 > MaxNumber then MaxNumber = Number2

Error type 2 :

statement number 6
logical error
if Number3 > MaxNumber then MaxNumber = Number3

[5](a)

Data is often sorted by computers. Why is this a useful operation?

[1]

It makes searching for data faster.

(b)(i)

Explain, using a diagram if you wish, how a binary search is used to locate an element in an array.

[3]

the data item in the middle is accessed.
the middle data item is compared to the search data. If the middle data is greater than the search data, the top half of the data file is discarded - if not, the lower half is discarded.
the process is repeated with the remaining records, discarding half of the file each time, until the search data item is located.

(ii)

When can a binary search not be used?

[1]

If the data is not sorted, a binary search cannot be used.

[6]

A decorating shop uses a paper-based system to manage its stock and customer orders.

A systems analyst has been asked to carry out a systems analysis and design for a new computer-based system. The systems analyst can use a number of techniques to find out how the existing system works. These include:

interviewing staff who use the current system
asking staff to complete questionnaires.

(i)

Describe one advantage of using interviews rather than questionnaires.

[1]

The interviewer can ask questions based on responses that the staff member makes, and he should be able to get more relevant information than from a questionnaire.

(ii)

State two other methods which the systems analyst might use in this case to find out about the current system.

[2]

observation - viewing what happens in the work place and seeing what jobs the staff carry out.
reading existing documentation about the current system.

(iii)

The systems analyst has agreed to produce an evaluation of alternative proposals for the solution. Describe how this should be carried out.

[1]

A number of different solutions can be costed, giving the advantages and disadvantages of each.

(iv)

Describe two activities which should take place during the testing of the new computer system.

[2]

selection of appropriate test data to cover all eventualities.
comparing actual results with expected results
debugging of the program - correcting any errors

(v)

For the new computer system to be successful, it needs to be developed on time. State one other basic requirement.

[1]

It needs to be completed within the budget allowed.

[7]

A mail order firm sells plants to gardeners. The firm is very keen to reward customers who spend a large amount of money or who introduce new customers to the firm. They send £10 or £20 vouchers to customers according to the following algorithm:

Statement
1	input Sales
2	input NewCustomerIntroduced
3	if ((Sales > 200) OR ((Sales > 100) AND (NewCustomerIntroduced = TRUE)))
4	then output "Send £20 voucher"
5	else if ((Sales > 100) OR ((Sales > 50) AND (NewCustomerIntroduced = TRUE)))
6	then output "Send £10 voucher"
7	else output "No voucher"

(a)(i)

State what the output will be if the inputs are:

Sales = 250 NewCustomerIntroduced = FALSE

[1]

Send £20 voucher

(ii)

State what the output will be if the inputs are:

Sales = 40 NewCustomerIntroduced = TRUE

[1]

No voucher

(iii)

State what the output will be if the inputs are:

Sales = 150 NewCustomerIntroduced = FALSE

[1]

Send £10 voucher

(iv)

State what the output will be if the inputs are:

Sales = 150 NewCustomerIntroduced = TRUE

[1]

Send £20 voucher

(b)

The firm decides to change the algorithm by removing statements 5 and 6. The algorithm now becomes:

Statement
1	input Sales
2	input NewCustomerIntroduced
3	if ((Sales > 200) OR ((Sales > 100) AND (NewCustomerIntroduced = TRUE)))
4	then output "Send £20 voucher"
7	else output "No voucher"

(i)

Tick one box to show which of the inputs given in part (a) would give a different output compared with the original algorithm.

[1]

inputs	tick one box
250 FALSE
40 TRUE
150 FALSE
150 TRUE

inputs	tick one box
250 FALSE
40 TRUE
150 FALSE	TICK
150 TRUE

(ii)

Suggest why the firm might have made this change.

[1]

they no longer wish to award £10 vouchers.

[8]

Bigtime is an antique business which specialises in buying and selling long-case (grandfather) clocks. When a clock owner contacts them with a clock to sell, a member of Bigtime staff carefully examines the clock and searches in a national database for information on similar clocks. If Bigtime and the customer can agree a price, the clock is purchased by Bigtime, and its details added to Bigtime's catalogue.

The following diagram illustrates the situation described above.

(i)

What is the name of this type of diagram?

[1]

Data flow diagram

(ii)

Draw the shape used in the diagram to represent a process.

[1]

(Rounded box)

(iii)

What type of object does the shadow box represent?

[1]

External entity

(iv)

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

[1]

clock details

(v)

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

[1]

Check clock

(vi)

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

[1]

Clock catalogue

[9](a)

Computer programs are often written using standard modules. Give two reasons why it is sensible to use standard modules.

[2]

It saves time - subroutines do not have to be programmed again.
The subroutines have already been tested and so they should work.

(b)

Why is it useful to organise a program into small sections?

[1]

It is easier to code, test and maintain small programs.

(c)

Many computer programs use iteration. What is meant by the term iteration?

[1]

Repetition of a section of program code.

(d)

What is meant by the scope of a variable in a computer program?

[1]

The section of program where a variable can be used.

[10]

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

The secretary in a small firm uses an integrated package for word processing and spreadsheet applications, and uses the available search facility, mail-merge, and macros.

The secretary is not an expert computer user, and the quality of the human computer interface (HCI) is consequently very important.

Describe in detail the facilities named above in green and describe in detail how the secretary might use them.

Also describe in detail how an HCI can be designed to be helpful for a non-expert user.

The secretary can use the search facility to find data. She may wish to find words in a document or data on a spreadsheet.

She may use the mail-merge to create a number of similar documents. She would use the word processor to create a document that, when printed, inputs data from the cells of a spreadsheet.

A macro is a single instruction which represents a small sequence of instructions. When the macro is run, the instructions are executed and this would save her time developing documents or spreadsheets.

As the secretary is not an expert computer user, she would benefit from a graphical user interface where applications and commands are represented by icons. To select these, she would click a mouse pointer on them.

It would also be helpful if each program uses the same icons in the same relative position on the screen, as she would find it easier to learn to use the programs..