Software Development

First and second number can be interchanged Accept suitable labels for DAT and Loop points For point 6 the 0s for ANSWER, NUMA, NUMB are optional but ONE must be initialised to 1.

Allow FT for BP5 if logic is correct.

Accept alternative mnemonics identified in the specification.

Examiner’s Comments

Most candidates were given some of the available marks for this question. Most were able to take two inputs and perform the addition of two numbers, storing the result in the accumulator. Candidates that lost marks did not successfully loop through the instructions correctly, didn’t output the correct answer and/or did not make use of DAT to subtract a value correctly.

Ignore case of identifiers in pseudocode

Only penalise excessive spaces within identifier names if obvious.

Examiner’s Comments

This question required exact answers only. Many candidates gained some marks, and there was a good distribution of marks. More successful programmers tended to get most of the marks available.

Examiner’s Comments

This was a relatively simple algorithm question which candidates could answer using pseudocode or program code. Many had not read the first part of the Question 5 (a) where the doCheck function was already shown and tried writing the doCheck function instead of passing a parameter to it as stated in the question. Many candidates were unable to show an understanding of how to open a file and write to it. However there were very many excellent responses to all parts of this question.

Exemplar 3

[Image redrawn from the original mark scheme by an AI model (Gemma 4 12B). It may contain mistakes.]

userInput = getInput("Enter an integer value :")
isCheckedValue = doCheck(userInput)
f = open("test.txt", "w")
f.write(userInput)
f.write(isCheckedValue)
f.close()

In this response the candidate has clearly shown input, calling the doCheck function and assigning the return value to a variable, File is opened and file name is enclosed in quotes and file is closed. The file name is then used to write to the file with the two values.

Example code:

num = input("enter a number")
value=doCheck(num)
txtfile =
openWrite("storedvalues.txt")

txtfile.writeLine(num)
txtfile.writeLine(value)
txtfile.close()

MP2 - doCheck is case sensitive

MP3 - need speech marks around file name

Examiner’s Comments

This was a relatively simple algorithm question which candidates could answer using pseudocode or program code. Many had not read the first part of the Question 5 (a) where the doCheck function was already shown and tried writing the doCheck function instead of passing a parameter to it as stated in the question. Many candidates were unable to show an understanding of how to open a file and write to it. However there were very many excellent responses to all parts of this question.

Exemplar 3

[Image redrawn from the original mark scheme by an AI model (Gemma 4 12B). It may contain mistakes.]

userInput = getInput("Enter an integer value :")
doCheckValue = doCheck(userInput)
f = open("test.txt", "w")
f.write(userInput)
f.write(doCheckValue)
f.close()

In this response the candidate has clearly shown

input, calling the doCheck function and assigning the return value to a variable, File is opened and file name is enclosed in quotes and file is closed. The file name is then used to write to the file with the two values.

One mark per stack diagram

Examiner’s Comments

This question was generally well answered although some candidates struggled to understand the concept of a stack and how data is pushed on to it and popped from it.

Examiner’s Comments

This was generally well answered, with the biggest misunderstanding being the way the subtraction occurs.

Examiner’s Comments

Many candidates were able to gain at least one mark on this question for stating that the addition would only be able to pop one number. The candidates who gained full marks were able to state the type of error correctly and explain why

there was only one value able to be popped after the subtraction.

Examiner’s Comments

The concept of stress testing a system by simulating heavy loads seemed to be poorly understood by most candidates. Many candidates often confused this with the general testing of a system to find bugs.

Examiner’s Comments

There was much confusion over testing a system in general to determine whether an individual route was effective in the graph given, and the actual performance of the system as a whole in terms of the overall time taken to actually perform the calculations required. The majority of candidates did not appreciate that performance modelling looks at the effect of escalating loads on a system.

Max 1 mark for Enqueue/Dequeue operations if description of effect on tail/head pointers not given

Examiner’s Comments

Many candidates identified the need to have a head/tail pointer but struggled to gain more than 1 mark by expanding on how enqueue and dequeue

operations would be implemented.

Some candidates continued to talk about push/pop operations for a queue rather than
enqueue/dequeue and often gave properties of a queue in general such as First In First Out rather than answering the question.

AO1: Knowledge and Understanding
Indicative content

• OOP defines an object as an independent entity
• OOP defines the attributes of the object and the methods that can be applied to it
• attributes could be private to restrict accidental changes
• Procedural the statements are executed in the order they are written

AO2: Application

• OOP allows for an object to be created from the queue
• Many instances of this queue can then be declared in the main program.
• Procedural will need each queue to be declared individually
• Procedural will need to make use of subroutines where the queue will need to be sent and returned each time.

AO3: Evaluation

• OOP you can create multiple instances of the queue as required by the program without having to re-write all of the declarations etc. In procedural you would have to write separate code for each new stack
• OOP reduces amount of code needed therefore fewer errors are likely as code is written once and then used multiple times
• OOP can reduce mistakes because the subroutines are self-contained in procedural it would need to make sure the correct values are passed and returned, or global variables may be required which uses excess memory.

Examiner’s Comments

Many candidates were able to identify some elements of OOP and Procedural programming to achieve a Level 1 response or were able to describe features in detail for a Level 2 response. Far fewer were able to apply this to the specific context to achieve a Level 3 response.

Those with good knowledge of OOP stood out in terms of giving clear evaluations of multiple queues generated from instance of the class, encapsulation to reduce side effects and possibilities for inheritance for different types of queues.

Many did not describe the necessary creation of enqueue and dequeue subroutines in procedural programming for each separate queue or the need to pass queues to or returning queues from subroutines.

[An examiner's marking symbol, not shown here.]

Misconception

There was a lot of confusion between inheritance and instantiation, e.g. “when creating several queues you can use inheritance, so all queues inherit attributes and methods”.

Candidates need to be clear that each instance of a class is assigned the attributes of the class and has access to all associated methods.

AO1
The spiral model has four quadrants (determine objectives, identify and manage risk, develop and test, plan next iteration). Client feedback then informs future development and prototypes which feedback into future revisions. Waterfall has a structured analysis/design/development/test flow. Progress to the next step is not made until the previous step is completed.

AO2
The spiral model relies on frequent client

feedback. Spiral produces functional prototypes where features are added incrementally. Spiral model has more focus on risk; projects may be modified or even dropped if risk is too great. Waterfall is much more structured and very reliant on getting the definition of requirements correct at the start; changes are harder to add in at a later stage. However, this forces the definition to be well understood.

AO3
Spiral involves client feedback, prototypes and evolving projects. Better option where
requirements may change. Waterfall is better where requirements are very clear to begin with and outcomes known. Spiral is better for risk management. If the programmer has a large team then waterfall may be more appropriate due to the clearly defined responsibilities at each stage.

Examiner’s Comments
Most candidates gained some marks on this question. Most could explain that spiral was iterative and waterfall was done in linear stages, but many did not expand on this. Few candidates linked their answer to the complex computer program mentioned in the question. Some candidates also described waterfall as iterative.

CAO

CAO

CAO

Examiner’s Comments
This was also answered well although some candidates used the word ‘iteration’ in their answer without going to describe what this means. As this was in the question, further detail was required such as repeating or looping through the text file.

Some points (for example 5 & 6) can be combined onto one line.

Example Solution:

procedure salesAnalysis():
    dayCount = 0
    salesTotal = 0
    dailySales =
openRead("Sales.txt")

    while NOT dailySales.endOfFile()
      dailySaleFigure = float
(percentageFile.readLine())
      salesTotal + =
dailySaleFigure
      dayCount + = 1
    endwhile
    dailyAverage = salesTotal
/dayCount
    print(“Over ” + dayCount + “
days there was a total sales of £” _+
salesTotal + “ and an average daily
sale of £” + dailyAverage)
    dailySales.close()
endprocedure

There are many different ways that this procedure could have been achieved. Therefore other alternative methods should be given credit.

Examiner’s Comments
Most candidates achieved a few marks, but few achieved the maximum marks available. The question states that pseudocode or program code could be used so a variety of answers were given.

The OCR pseudocode guide gives guidance on how to write pseudocode including data structures, constructs, and reading/writing to file. Some candidates wrote neither pseudocode or program code and therefore were given no marks.

Many candidates remembered to open the sales file, but many forgot to close the file. Initialising the variables before the loop was also missed by a number of candidates.

Increasing the total was included in many responses, although many forgot to cast the total to a numeric data type to enable this to work correctly.

Many candidates achieved the last 2 marks for calculating the average and then displaying the calculated values. Some missed the final output as the text was incorrectly concatenated with the variable values.

Exemplar 3

[Image redrawn from the original mark scheme by an AI model (Gemma 4 12B). It may contain mistakes.]

SalesFile = open("Sales.txt")
numDays = 0
total = 0
while not EOF:
    line = SalesFile.readline()
    Sales = Float(line)
    numDays = numDays + 1
    total = total + Sales
endwhile
SalesFile.close()
print("The number days sales are " + Str(numDays))
print("The total sales are " + Str(total))
average = total / numDays
print("The average sales are " + Str(average))

Exemplar 3 was given full marks. The candidate has gained the first mark for initialising the variables “numofdays” and “total”. The second mark has been awarded for the first line, which opens the sales file and closing the file after the

loop has finished. The while loop gains the third mark which repeats until the end of the file is reached. The fourth mark is awarded for reading each line of the file correctly. The fifth mark correctly increases total in each iteration. Sale has been correctly converted to a “float” data type beforehand to make this possible. The sixth mark is awarded for calculating the average on the penultimate line. The final mark is awarded for printing the number of days, total sales and the daily average. This has been concatenated correctly with a plus symbol. Some candidates used the comma which was also acceptable.

The syntax provided in this example relates to Python whereas some candidates wrote pseudocode or another high-level language. Some candidates lost marks for writing the steps in everyday English which is not what the question stipulated.

Examiner’s Comments
This was generally answered well although some candidates picked Integer for the data type which would not be accurate given that averages are likely to be a decimal value. There are a range of data types that support decimal values, any of which would be acceptable as an answer.

Example answer

class Worker
  private name
  private attendance

  public function getName()
     return name
  end function

  public function
  getAttendance()
     return attendance
  end function

  public procedure
  setName(newName)
     name = newName
  end procedure

  public procedure
  setAttendance(newAttend)
     if newAttend >=0 and
     newAttend <=100 then
        attendance =
        newAttend
     end if
  end procedure
end class

Can be completed either by using MOD / DIV or by using repeated subtraction as in LMC example

Correct answer only. Penalise spelling if incorrect.

Do not accept £ sign in first bullet point.

7

35

3

7

35

5

7

35

6

X Y Z variable alternatives are acceptable Solution:

X = input()
Y = 5
Z = 0
if X >= Y then
   Z = Y
else
   Z = X
Endif

AO1.1

• Automatic Number Plate Recognition (ANPR) could be used. This makes use of OCRto turn number plates on camera into digital characters.
• Use of a token/ticket could be used when cars enter the car park which is time stamped.
• Staff could be employed to manually record the time cars enter the car park and then again when cars leave.
• Sensor could be used to detect cars entering / leaving the car park.
• Photographs of vehicles can be taken when cars enter / leave the car park. These can be time stamped.

AO2.1

• Data will be input into an algorithm that will work out the price based on amount of time car has spent in car park.
• If the car park is considering storing videos / photographs of the cars then they will need to follow current data protection legislation as these may contain faces of people.
• Car park users may see this as an invasion of privacy. Civil liberty issues as movements are being tracked / monitored.
• Automated systems are likely to be more reliable and will produce statistical data that

can be analysed better.
Manual methods may be prone to human error. Automatic methods will allow for quicker processing than if a human was doing it.

• Lower overheads as no human to employ.
• They could connect to the other databases (e.g. police and DVLA) to check that cars are genuine (e.g. can check if cars have been stolen)
• If connecting the cameras over the internet, then this would make them susceptible to hackers and therefore security methods would need to be put in place.

AO3.3

• If automated systems are used then this can lead to improved customer satisfaction and lower costs due to streamlined system. However this could lead to less employment in the local area as computer systems taking over jobs.
• Some people may be afraid of using carpark due to cameras.
• Data protection laws should mean consumers are protected o System secure o Data only stored for a short time o Only relevant data stored