CG1 Computing Jan 2009

[1]	A company that provides airport car parking has a web site where customers select a car park and pay to park their car while on holiday. The company has purchased a list of email addresses of people who have recently booked flights. Briefly describe how the company could use these email addresses to sell more car parking spaces and possible benefits for the company of using email in this way.	[3]
	the company can contact potential customers who have booked flights inexpensive method of advertising - no need to pay for paper, envelopes, stamps. the company can send special offers to entice customers to park their cars.

[2]	Home computers often store large amounts of data, such as photographs, videos and personal files on hard disc. As a result of a disaster such as a house fire or flood the hard disc could be damaged and the data lost. Describe a suitable strategy for backing up the data and briefly describe how the data may be restored.	[4]
	the data should be copied to another storage medium (eg DVD) the data should be copied regularly the medium should be safely stored in a different location if necessary, the data can be recovered by copying it back to the original disc.

[3]	Briefly describe the main function of the following components of a computer:
(a)	control unit;	[1]
	manages the execution of instructions
(b)	arithmetic and logic unit;	[1]
	performs calculations
(c)	register;	[1]
	temporarily stores data
(d)	bus.	[1]
	a path down which data can travel around the computer

[4]	Smash Hits is a successful DVD rental shop with increasing customer numbers. Smash Hits currently store the details about DVDs, customers and rentals on paper which is kept in files behind the counter. It is becoming difficult to find the paperwork for a particular DVD, customer or rental.
(a)	Briefly describe two other possible problems with the current paper-based system.	[2]
	paper files can easily become lost changing customer details on paper can be difficult and takes time
(b)	The owner of Smash Hits has purchased a computerised database system. Describe how this system could solve the problems described above.
	backups of the data can be made to prevent data loss data on a database can easily be edited
	Also describe a useful report that the new system might produce.	[3]
	report of all DVD rentals that have not been returned or are overdue.
(c)	Smash Hits will be storing additional customer information such as bank details in the new computerised database system. Describe three ways in which the Data Protection Act will apply to the data stored by Smash Hits.	[3]
	data must be obtained fairly and lawfully data must be kept secure to prevent unauthorised access data must only be used for its intended purpose

[5]	Verification checks are carried out on student data stored on a computer at a college. Briefly describe when verification checks would be carried out on the student data and explain the purpose of verification.	[2]
	verification is carried out when data is entered ...to make sure that the data has been entered correctly.

[6]	Many people, including children, benefit from using the Internet to make new friends in chat rooms as well as exchanging ideas in forums.
	Discuss the benefits and drawbacks of using the Internet for these purposes.	[6]
	can meet people from other countries or other cultures can ask for and exchange information for research purposes is available at any time (24/7) people may not be who they say they are may come into contact with undesirable people selling illegal material may develop a loss of proper social skills

[7](a)	Describe in detail the role of the operating system in managing the resources of a computer.	[5]
	manages input and output from peripheral devices such as a keyboard or printer loads and runs programs manages the loading and saving of data onto backing store device such as a hard disc... ...and keeps the FAT (File Allocation Table) updated so data can be retrieved manages memory space, allocating memory to different programs.
(b)(i)	A computer's hard disc can become fragmented. Explain the term fragmentation and briefly describe the effect that fragmentation will have on disc access.	[2]
	a file can be split up into a number of fragments, each stored in different areas of the disc. badly fragmented files will cause disc access speed to be reduced
(ii)	Describe what happens during de-fragmentation.	[1]
	parts of fragmented files are re-arranged so the parts are stored together.

[8]	Computer files can be organised in serial or sequential order.
(a)	Briefly describe how records are added to:
(i)	a serial file;	[1]
	a new record is added on to the end of the file.
(ii)	a sequential file.	[2]
	the new record has to be inserted into the file, usually by copying each record into a new file and inserting the new record at the right place.
(b)	Computer files can contain fixed length or variable length records. Describe the difference between fixed and variable length records.	[4]
	fixed length - each record is the same size when stored... ...variable length records are different sizes, with record separators between each record. files with fixed length records are larger than files with variable length records files with fixed length records are faster to process as the computer can calculate where each record begins and ends.

[9]	Below is an incomplete algorithm intended to determine the largest of three integers. Line 12 is incomplete.

	1 repeat
	2 input Number1
	3 until ( Number1 is an integer )

	4 repeat
	5 input Number2
	6 until ( Number2 is an integer )

	7 repeat
	8 input Number3
	9 until ( Number3 is an integer )

	10 set Biggest = Number1

	11 if Number2 > Biggest then Biggest = Number 2
	12 if Number3

	13 output Biggest

(a)	Explain the purpose of the repeat - until loop shown below.	[2]
	1 repeat
	2 input Number1
	3 until ( Number1 is an integer )
	a method of validation that keeps requesting a number to be input ...until the number input is an integer
(b)	Complete line 12 of the algorithm.	[1]
	if Number3 > Biggest then Biggest = Number3

[10]	"In the future we will be able to talk to computers and keyboards will not be required".
	Discuss the advantages and disadvantages of speech input.	[6]
	There is no need for keyboard taking up room on the desk Speech input is faster than typing... ...and can be done by the handicapped or people doing other things with their hands eg surgeons, drivers, pilots. There may be problems with background noise eg in a noisy office Users may have vocal problems such as sore throats that makes their voice difficult to recognise There may be problems with different words that sound the same Eg too, two, to

[11]	Briefly describe the most suitable use for each of the following protocols:
(a)	FTP ( File Transfer Protocol ):	[1]
	downloading a file over the Internet
(b)	HTTP ( Hypertext Transfer Protocol ):	[1]
	transferring web pages over the Internet
(c)	SMTP ( Simple Mail Transfer Protocol ):	[1]
	transferring emails over networks

[12]	Below is an algorithm.
	Algorithm FindTotal

	Num1 is integer {number input by user}
	Num2 is integer {number input by user}
	declare subprocedure AddTwoNum {procedure to find the total of two integer and output the answer}
	Total is integer {variable to store the answer}
	start
	set Total = Num1 + Num2
	output "the total is ", Total
	end
	startmainprog
	output "type in first number"
	input Num1
	output "type in second number"
	input Num2
	call AddTwoNum
	endmainprog
(a)	Write down one example of annotation from the algorithm above and explain why annotation is used in computer programs.	[2]
	{number input by user} Comments used to explain to other programmers how the algorithm works
(b)	Using examples from the above algorithm, describe the difference between local and global variables.	[4]
	Global variables can be used throughout the program Eg. Num1, Num2 Local variables are declared inside a subroutine and can only be used inside that subroutine. Eg. Total

[13]	In a computer different data types use different amounts of memory.
(a)	Give an example of data that could sensibly be stored as	[2]
(i)	integer data type
	Number of people in a bus
(ii)	real data type
	Average daily temperature
(b)	Using an example of data that could sensibly be stored in each data type, compare the amount of memory required to store a character with the amount of memory required to store a string.	[4]
	A character such as 'H' ...would take 1 byte of storage A string such as 'MONKEY' ...would need 6 bytes - one for each character

[14]	A bank has an internet site and an intranet.
(a)	Give two examples of information which might sensibly be found on their internet site.	[2]
	Opening times Current rates of interest for different types of bank account
(b)	Give two examples of information which should only be found on their intranet, explaining why this information should not be on the internet?	[4]
	A list of internal telephone numbers... ...not available to outside callers Forms for bank administration... ...that are only needed by bank employees.

[15]	Explain how a linear search algorithm would determine whether an item called SearchValue is present in an array called SearchArray.	[3]
	Starting from the first value, each value of SearchArray is compared with SearchValue... ...until a match is found... ...or the end of the array is reached and no match has been found.

[16]	A water company monitors the amount of water in its reservoirs and the amount of rain falling. During a water shortage, the company is able to ban its customers from using hosepipes. In extreme conditions the water company has the power to ration the water supply to its customers, by turning off the supply for several hours per day.
	The algorithm used by the company is shown below:

	Statement
	1 input ReservoirLevel
	2 input DaysSinceLastRain
	3 if (( ReservoirLevel < 20% ) OR
	(( ReservoirLevel < 30% ) AND ( DaysSinceLastRain > 21 )))
	4 then output "Rationing"
	5 else if (( ReservoirLevel < 40% ) AND ( DaysSinceLastRain > 14))
	6 then output "Hosepipe ban"
	7 else output "Normal"

(a)	State what the output will be when the inputs are:
(i)	Reservoir level = 35% Days since last rain = 16	[1]
	Hosepipe ban
(ii)	Reservoir level = 32% Days since last rain = 12	[1]
	Normal
(iii)	Reservoir level = 15% Days since last rain = 12	[1]
	Rationing
(iv)	Reservoir level = 28% Days since last rain = 25	[1]
	Rationing
(b)	The water company decides to change statement 3 so it becomes:

	3 if (( ReservoirLevel < 20% ) OR
	(( ReservoirLevel < 25% ) AND ( DaysSinceLastRain > 21)))

(i)	State which part or parts of (a)(i) to (a)(iv) now gives a different output.	[1]
	(iv)
(ii)	What will the new output or outputs be?	[1]
	Hosepipe ban

[17]	When a student applies to do a course at a particular music college, he or she completes an application form and asks someone ( a referee ) to supply a reference to the College. When the College receives the application and reference, its admissions tutor checks on a national database any musical examination results claimed by the student. The student is then interviewed and if successful he or she is added to the list of students approved for entry to the College.
	The situation described is shown in the data flow diagram below:


(a)	Why do systems analysts find data flow diagrams very useful?	[1]
	Pictures explain complex situations in a simpler way than text.
(b)	What type of object dose the rounded box represent?	[1]
	process
(c)	Draw the shape used in the diagram to represent an external entity.	[1]

(d)	Give a suitable name for the object shown as A in the diagram.	[1]
	Application form
(e)	Give a suitable name for the object shown as B in the diagram.	[1]
	Referee
(f)	Give a suitable name for the object shown as C in the diagram.	[1]
	National Music Examination Database
(g)	Give a suitable name for the object shown as D in the diagram.	[1]
	Interview student

[18]	A large government department, having decided to update one of its computer systems, has carried out a feasibility study and has awarded the contract to update the system to a company called Cymrix. Staff at Cymrix will now analyse the current system and design a new system.
	Describe in detail the activities carried out during the feasibility study
	Describe in detail the activities that will be carried out during the analysis and design stages.
	Describe in detail the different methods of changeover that could be considered by Cymrix.	[12]
	During the feasibility study, the existing system will be studied by reading existing documentation... ...by interviewing staff or customers... ...by asking staff and customers to fill in questionnaires... ...and by observing the system at work. Decisions will be made about whether a new system is cost-effective, viable and can be put in place in the allowed time. In the analysis and design stages, data flow diagrams may be produced... ...the design of the structure of data will be decided upon... ...and algorithms for the programs needed will be written. Changeover to the new system can be done directly - ie. suddenly stopping the old system and starting the new one... or Parallel Running - using both old and new systems together until it is known that the new system will work... ...Phased changeover, where different parts of the new system are introduced at different times... ...or Piloting the new system in different parts of the company.