Computing (Modular) 
 CP1
 June, 2002
(2 Hours)

1. The Human Computer Interface (HCI) is normally considered to be of great importance when a new computer system is developed.  
(i)  Give two reasons why the HCI is considered to be of great importance. [2]
   
(ii)  Describe two features you would expect to see in a well-designed HCI. [2]
   
 
2. In each case, give an example of data which would best be stored in :  
(i)  an integer data type [1]
   
(ii)  a real data type [1]
   
(iii)  a character data type [1]
   
(iv)  a string data type [1]
   
(v)  a boolean data type [1]
   
 
3. A binary search is often used to attempt to locate one item in a set of data.  
(i)  When is it not possible to use the binary search with a set of data? [1]
   
(ii)  When a binary search is possible, what is its advantage over a linear search? [1]
   
(iii)  A binary search is used to search for the number 14 in the following table:  
 
7 12 14 16 21 21 26
 
  Write down in order the numbers which are accessed to complete the search. [2]
   
 
4. A retirement home hires care assistants to help to look after the residents. When a care assistant is interviewed for a job by the manager, he or she supplies their national insurance number, and a check is made on a national register concerning their previous employment record. When this has been done, the manager makes a response to the care assistant.

The following diagram shows the situation described.

  
 

 
(i)  State the name of this type of diagram. [1]
   
(ii)  Describe in detail why this type of diagram is particularly useful. [2]
   
(iii) What type of object does a rounded box (for instance "Check register" in the above diagram) represent? [1]
   
(iv) What type of object does an open box (for instance "National register" in the above diagram) represent? [1]
   
(v) Give a suitable name for the object shown as X in the above diagram. [1]
   
  (vi) Give a suitable name for the object shown as Y in the above diagram. [1]
   
 
5. HTML is an example of a programming language used in the design of web pages. Describe two desirable features of a programming language used for the purpose. [2]
   
 
6. Two-dimensional arrays and records are useful data structures.  
(i) A warehouse contains many different types of fresh food products, each of which has a four-digit code and the week number in which it was produced.

The diagram below shows part of a two dimensional array used to store information in this case.

  
 
  Week Number
  22 23 24 ...
* ... ... ... ...
* ... ... ... ...
* ... ... ... ...
* ... ... ... ...
 
  I. Copy this diagram and replace the asterisks (*) in the left hand column to show how the array might be used to store this information. [1]
   
  II. What data might usefully be stored in the elements of this array? [1]
   
(ii) The same warehouse employs a large number of staff. Give an example to show how a record could be used to store information about one member of staff. [2]
   
 
7. A team of programmers is designing safety systems for an underground railway. They wish to ensure that the programs they write are of high quality.  
(i) Explain in each case why they normally:  
  I. organise the programs into small sections. [2]
   
  II. use standard modules [2]
   
(ii) They also use self-documenting code. State what is meant by self-documenting code. [1]
   
(iii) Give two reasons why testing these programs will be a major operation. [2]
   
(iv) Name two types of errors which often occur in computer programs. [2]
   
 
8. A school library uses a paper-based system to control the loan of books to staff and students. A new computer-based system is required to hold records of:
  • the borrowers;
  • the books;
  • book loans.
  
(i) Various stages in the system life cycle are named below. In each case, describe in detail how you would carry out the stage for the school library system:  
  I. requirements analysis [2]
   
  II. design [2]
   
(ii) Describe two different approaches which could be adopted for the changeover. [2]
   
(iii) Describe two types of documentation which would be required. [2]
   
(iv) Explain why the following might be required during the life time of the new system:  
  I. corrective maintenance; [1]
   
  II. adaptive maintenance. [1]
   
 
9. The Goodread book club sells books to its customers by mail-order. Goodread is planning to send a special gift to reward customers who have either bought a certain number of books, or who have bought a smaller number of books as well as having introduced a friend to the book club.

The algorithm used is shown below:

  
 
Line
1 input number-books-bought;
2 input introduced-friend;
3  
4 if ( ( number-books-bought >= 10) OR
5 ( ( number-books-bought >= 5) AND ( introduced-friend = TRUE) ) )
6 then output "Send Gift"
 
(i) State what will happen if the two inputs are:  
  I.  6 and TRUE; [1]
   
  II. 4 and FALSE; [1]
   
  III. 4 and TRUE; [1]
   
  IV. 12 and FALSE. [1]
   
(ii) If the word AND in line 5 was changed to OR, one of the parts of question 9(i) would give a different result. Whcih one would this be? [1]
   
 
10. In the following question, additional credit (up to 3 marks) will be gained if your answer demonstrates skill in written communication.  
  A large office makes extensive use of an integrated software package which provides a number of facilities. Examples of such facilities are:
  • mail-merge;
  • macros;
  • data portability.

Describe in detail the facilities available in an integrated package, with special reference to the three terms given above.

 [7+3]