CP2 Computing January 2001

1.	A public library owns thousands of books, CDs and other items. Each item is given a unique identification code made up of two letters and four digits, for instance GR2351. Validation is used on the codes.
(i)	What is the purpose of validation?	[1]
	To test if the data is reasonable before it is processed.
(ii)	Describe two types of validation which might be applied to this code, stating in each case how it might be applied.	[4]
	Length check - to make sure the codes are all 6 characters. Type check - to make sure the first two characters are letters and the last four are digits.

2.	Sue Evans runs a small business in which she tries to trace people's family histories. Customers are asked about their parents, grandparents and other relatives and then Sue refers to census information, parish records and other documents. She also has a network of contacts around the world whom she telephones: these are people in a similar line of business who can help her in the search for information. Currently, Sue does not use a computer. For each customer, she creates a paper file which she may add to over several months. Before presenting all her findings to the customer, she produces an attractive typed report detailing all the information gathered, and draws a decorative family tree diagram. Sometimes she photocopies valuable and attractive documents and includes them in the final file.
(i)	Explain why this paper-based system will cause Sue some difficulties.	[2]
	The papers will take up a lot of storage space. It would be slow to locate a particular piece of paper.
(ii)	Sue has now obtained some information about a computer system consisting of a personal computer and specialist software which may be able to help her run the business more efficiently.
I	Informaton is required about each relative of the customer. State two different items of information which the system could usefully store about each relative.	[2]
	full name date of birth
II	Describe two features that this specialist software would need.	[2]
	search facilities to speedily find data in her database email facilities to send messages to her contacts
	Describe two special hardware items which might also be useful for Sue, with a reason in each case.	[2]
	a modem - so that she can use email and the Internet. scanner - to scan documents which are saved in the database

3(a)	Using a diagram, explain in detail each of the following file structures. In each case, also describe how a new record is inserted:
(i)	serial access file
	Records are stored in the order in which they occur. A new record is added onto the end.
(ii)	sequential access file	[3]
	Records are stored in sorted order (of a key field). A new record would need to be 'inserted' in the file at the right place.
(b)	Describe an application of each of the following file structures, making it clear in each case why the file structure is appropriate in this case.	[2]
	A transaction file for a mail-order business may be stored as a serial access file. As orders are received they are placed on the file and processed in the order in which they are received.
(ii)	sequential access file	[2]
	An exam board may store data sorted in order of school name so that when certificates are printed out, all the certificates from one school will be together.

4	A certain computer uses a word length of 32 bits.
(i)	What is meant by the term word in this context?	[1]
	The amount of data the computer can process at a time.
(ii)	What advantage is derived from using a long word length?	[1]
	The computer will be able to process data faster so programs will execute quicker.

5.(a)	Explain what is meant by the term database.
	A collection of related files (tables).
(b)(i)	Give two reasons why data duplication is often considered very undesirable.	[2]
	It is wasteful of storage space to save identical copies of data in different places. It may lead to data inconsistency - two copies of the same data may be different (eg spelled differently)
(ii)	Describe how a database system can avoid duplication.	[1]
	Store all the data in a central database and use a network to allow users to access it from a number of workstations. All data would only be stored once.

6.	The Megahire car hire company has a large number of customers (mainly other firms) who hire cars regularly. Megahire uses a large computer system to run its business. It uses batch processing and interactive systems for different applications.
(i)	Describe what is meant by batch processing and describe an application where Megahire might sensibly use a batch processing system, amking it clear why a batch processing system is suitable in this case.
	Collecting similar jobs to run them together. The firm might run their payroll system using batch processing. There is no immediacy so it can be run at off-peak times. There is no need for human intervention during processing.
(ii)	Describe what is meant by an interactive system and describe an application where Megahire might sensibly use an interactive system, making it clear why an interactive system is suitable in this case.	[3]
	The car hire booking system would use an interactive system as there is a need for human interaction when bookings are made or cancelled.

7(a)	Describe three functions of the operating system of a personal computer.	[3]
	controls the loading and running of programs. controls the use of memory - decides what is stored where. controls the operation of input and output devices.
(b)	A number of hand-held computers now use handwriting recognition as a means of input. Describe one advantage and one disadvantage of this input method.	[2]
	Advantage : There is no need for paper. Disadvantage : There may be accuracy problems if someone's handwriting is not very clear.

8.	Chris Williams is responsible for computer security and computer-related ethical and legal issues for West Wales Bank(WWB).
(i)	One particular concern is the possible theft of valuable data held in the Bank's computer system. Describe three methods by which the risk of theft can be reduced.	[3]
	physical security - ie make sure the doors to computer rooms are properly locked. passwords - make sure that data can only be accessed by entering a correct password. encryption - coding the data to make it meaningless to thiefs.
(ii)	Another concern is the accidental loss of data. Describe one method by which the risk of accidental loss can be reduced.	[1]
	Backups of all current data should be made.
(iii)	Chris has to be careful that the Bank complies with all the computer related legislation, such as the Data Protection Act. Describe three ways in which the Data Protection Act will apply to WWB.	[3]
	WWB will need to ensure that all data is only used for the purpose for which is was registered. WWB will need to make sure that data is secure. WWB will need to make sure that data is kept up-to-date.
(iv)	There are concerns in WWB about computer-related health and safety issues. Describe the likely nature of the concerns and how the problem might be eased.	[2]
	There may be a concern that workers will get eye-strain or back/neck strain from sitting at the computers all day. Ergonomics - there must be proper seating and lighting provided.
(v)	There are also concerns in WWB about the possibility of staff being made redundant. Describe the likely nature of the concerns and how the problem might be eased.
	staff will be afraid that computers will replace them - ie do their jobs and work at it 24 hours a day. staff will need to be re-trained to do skilled jobs which computers are unable to do.

9.(a)	Describe, with the aid of a diagram, the main features of each of the following network types:
(i)	bus network;	[2]
	All computers are linked along one 'bus' - a cable which they share to transmit data.
(ii)	token ring network.	[3]
	All computers are linked in a loop. Data is transmitted round the ring as a 'token' with information about its destination. This token is then collected by the receiving computer.
(b)	Computer networks tend to be particularly prone to attack by computer hackers. Give one reason why this is the case.	[1]
	It is easy for a hacker to hide his identity and access data on a computer system often without even being detected.
(c)	Peripherals such as printers often use handshaking in communicating with the computer. Give an outline example of handshaking as applied to the use of a printer.	[3]
	A computer sends a request to a printer for output. the printer sends back a signal indicating that it is ready to receive data. the computer receives this signal and sends the data.

10.	In the following question, additional credit (3 marks) will be gained if your answer demonstrates skill in written communication. The students and staff in a college make extensive use of email and the internet, and also the college's own intranet. Describe in detail how email, the internet and the intranet would be useful to both staff and students. In your answer, you should consider the types of information being stored and communicated, and the purpose of the storage/communication.	[8+3]
	Email is a method of communicating between two computer users and could be used by students to request help from staff about any problems or to send them completed pieces of work. The staff could quickly respond to any assistance or send back assessed and corrected work to the student. The Internet could be used by students to research and retrieve information to help with assignments or request information using bulletin boards or news groups. Students could also publish their completed research on a website which could then be accessed by other students. Staff could also set up websites to advertise the college and the courses it offers to try to attract prospective students. The college intranet could be used to store frequently needed information or pages of information about the college eg course timetables, plan of the college site. Students could also use the intranet for internal emails.