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Date	November 2020	Marks available	4	Reference code	20N.1.SL.TZ0.7
Level	SL	Paper	1	Time zone	no time zone
Command term	Outline	Question number	7	Adapted from	N/A

Question

A school has a local area network (LAN) connecting its computers and peripheral devices. The LAN also provides access to the internet.

Users have been troubled by slow speeds when accessing the internet.

Describe the role of a router in this network.

[3]

Outline two reasons why there might be a reduction in data transmission speed at certain times.

[4]

Outline two measures that the school could take to safeguard its data from unlawful access via the internet.

[4]

The inventory of office supplies used in the school is stored on the computer as a single file.

Each of the office supplies in the inventory (such as paper, ink, toner, printers, pens, staplers, pencils and scissors) has a unique ID number, name, maximum quantity, minimum quantity and remaining quantity.

Outline the steps in an algorithm that would output a list of supplies with the quantity to be ordered.

[4]

Markscheme

Award [3 max].
controls the flow of data in the network;
inspects address of data packets;
directs to the appropriate network path/ selects a path between networks (by inspecting address of data packets);
securely transmits data packets (across that path toward the intended destination);

Award [4 max].
malicious software/spyware/malware / viruses;
attacking the system;

the type of connection;
valid outline for the slow down (depending on the type of connection);

Note: There are many types of internet connection: wireless connections, wireless hotspots, mobile internet, broadband connections, fixed wireless and satellite connection, cable, DSL;

hardware malfunction;
internet speed can considerably slow down if modem-router configuration is not correct / updated;

external factors;
during the peak hours of daytime the most visited websites encounter more network traffic than what has been anticipated;

NOTE: Accept examples. For example, too many students try to connect to an e-learning site at the same time.

Mark as 2 and 2

Award [4 max].
Preventing unauthorized access/No access without user names/passwords;
which should be regularly changed/made difficult to guess;

Data should be encrypted;
Allowing only those with decrypting code access;

Teachers/students should be trained for safe practices;
to create a risk-conscious /security-aware culture within the school;

Installation of virus checkers/spyware software;
to prevent damage to data files or the system / to prevent data being extracted from the files/system;

Mark as 2 and 2

Note: Accept appropriate measures such as physical security measures / access control / data security / network and communication security / user awareness and education, etc.

Award [4 max].
Award [1] for looping through the inventory file;
Award [1] for reading the supply data record (ID number, name, maximum quantity, minimum quantity and remaining quantity);
Award [1] for checking if the quantity remaining is less than minimum quantity;
Award [1] If so, calculate the quantity to be ordered (number to buy) / as the maximum quantity minus the quantity remaining;
Award [1] for outputting the name/ID number of the office supply and the number to buy;

Example 1:

while not end of inventory file
    read supply data record from file
    if remaining quantity < minimum quantity
      then
         numbertobuy = maximum quantity – remaining quantity
         output ("Reorder ", ID, name, numbertobuy)
    end if
end loop

Example 2:

for each item in the inventory loop
  with item do
    if remaining quantity < minimum quantity then
      output "Reorder ", ID, name, (maximum quantity – remaining quantity)
    end if
  end do
end loop

Examiners report

Candidates generally recognised that a router directs data between networks and gained a mark for this. However, most answers didn't really go beyond that point and concentrated more on access to the internet. Some candidates did recognise the role of addresses in data packets to ensure they arrived at the correct destination.

The vast majority of candidates who achieved marks in this question, which asked for two reasons why there may be a reduction in data transmission speed at certain times, gave answers that may fit into category 'external factors'. An example of this was high demands on bandwidth due to many students accessing the network at the same time. Sometimes, candidates gave more than one answer related to this same category. Other categories, such as malicious software, type of connection and hardware malfunction, were largely overlooked by candidates.

Candidates recognised at least one measure that a school could take to safeguard its data from unlawful access via the internet, with correct answers based on authentication of users or encryption. A small number of candidates recognised the benefits of anti-virus software. However, candidates could also have discussed the benefits or training staff or users in safe practices.

Candidates were required to write the main steps in an algorithm to output a list of office supplies with the quantity to be ordered. Candidates who gave a list of logical steps written in the style of an algorithm, rather than as a purely descriptive answer, achieved higher marks. Marks were generally lost when candidates failed to recognise the need for a loop to check the whole file, or if they were not specific enough about either what was being ordered, or the quantity of the order. Sometimes, candidates would output the office supply item and its order quantity but failed to show how the order quantity was determined.

Syllabus sections

Topic 4: Computational thinking, problem-solving and programming » 4.2 Connecting computational thinking and program design

Show 59 related questions

18M.1.SL.TZ0.12a:

The collection DATA contains the following data:

2, 4, 1, −2, −4, 1, 0

Consider the following pseudocode:

COUNTER = 0
SUM = 0
DATA.resetNext()
loop for X from 0 to 6
  if DATA.getNext() > 0
    ARRAY[X] = DATA.getNext()
    COUNTER = COUNTER + 1
    SUM = SUM + ARRAY[X]
  end if
end loop
output SUM/COUNTER

Trace the pseudocode using the table below:

18N.1.SL.TZ0.7:

Construct a trace table for the following algorithm

A = 3
B = 7
loop while B >= A
  A = A + 1
  output(B − A)
  B = B − 1
end loop

19N.1.SL.TZ0.7:

Construct a trace table for the following algorithm.

K = 1
N = 1
M = 2
loop while K < 5
   output(N,M)
   K = K + 1
   N = N + 2
   M = M * 2
end loop

21M.1.SL.TZ0.8:

List the output from the given algorithm for the following input.

2, 6, 8, 9, 12, 15, 18, 20

loop for Count from 0 to 7
    input NUMBER
    if NUMBER div 2 = NUMBER / 2 then
        if NUMBER div 3 = NUMBER / 3 then
        output NUMBER
        end if
    end if
end loop

19N.1.SL.TZ0.10a:

Consider the following algorithm.

N = 372
X = N DIV 100
Y = X + 10 * (N MOD 100 DIV 10)
Z = Y + (N MOD 10) * 100

Determine the values of variables X, Y, and Z after execution of this algorithm. Show your working.

19M.2.SL.TZ0.4b:
Using the rules and initial values above, construct the pseudocode that would enable the area of the sea ice and the sea level rise to be calculated if there was an increase of 0.04 °C in the ocean surface temperature.

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Topic 4: Computational thinking, problem-solving and programming

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