Cambridge International AS & A Level

INFORMATION TECHNOLOGY 9626/12

Paper 1 Theory May/June 2022
MARK SCHEME
Maximum Mark: 70

Published

This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the
examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the
details of the discussions that took place at an Examiners’ meeting before marking began, which would have
considered the acceptability of alternative answers.

Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for
Teachers.

Cambridge International will not enter into discussions about these mark schemes.

Cambridge International is publishing the mark schemes for the May/June 2022 series for most
Cambridge IGCSE, Cambridge International A and AS Level and Cambridge Pre-U components, and some
Cambridge O Level components.

This document consists of 11 printed pages.

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Generic Marking Principles

These general marking principles must be applied by all examiners when marking candidate answers.
They should be applied alongside the specific content of the mark scheme or generic level descriptors
for a question. Each question paper and mark scheme will also comply with these marking principles.

GENERIC MARKING PRINCIPLE 1:

Marks must be awarded in line with:

• the specific content of the mark scheme or the generic level descriptors for the question
• the specific skills defined in the mark scheme or in the generic level descriptors for the question
• the standard of response required by a candidate as exemplified by the standardisation scripts.

GENERIC MARKING PRINCIPLE 2:

Marks awarded are always whole marks (not half marks, or other fractions).

GENERIC MARKING PRINCIPLE 3:

Marks must be awarded positively:

• marks are awarded for correct/valid answers, as defined in the mark scheme. However, credit
is given for valid answers which go beyond the scope of the syllabus and mark scheme,
referring to your Team Leader as appropriate
• marks are awarded when candidates clearly demonstrate what they know and can do
• marks are not deducted for errors
• marks are not deducted for omissions
• answers should only be judged on the quality of spelling, punctuation and grammar when these
features are specifically assessed by the question as indicated by the mark scheme. The
meaning, however, should be unambiguous.

GENERIC MARKING PRINCIPLE 4:

Rules must be applied consistently, e.g. in situations where candidates have not followed
instructions or in the application of generic level descriptors.

GENERIC MARKING PRINCIPLE 5:

Marks should be awarded using the full range of marks defined in the mark scheme for the question
(however; the use of the full mark range may be limited according to the quality of the candidate
responses seen).

GENERIC MARKING PRINCIPLE 6:

Marks awarded are based solely on the requirements as defined in the mark scheme. Marks should
not be awarded with grade thresholds or grade descriptors in mind.

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Question Answer Marks

1 Five from: 5

By interviewing the family, the students will obtain up to date

information/census is two years old/census data may be out of date
More/detailed information will be obtained as the census may not contain all
the information required/has limited information/fewer details
They are able to collect only as much information as they require/the census
may include information they do not need …
…might take time to filter extra information out
It may be cheaper to visit the streets than the school paying transport costs to
get the students to city hall
It may be too time consuming to collect direct data / to go to every house in
these streets / only need to make one trip to city hall
The study might be limited as it is only five streets/the census would allow
them to extend the survey
Residents might not be at home when the students call/nobody at home
would not be a problem with the census
Data may take time to collate and present in a meaningful way/census data is
already collated and presented so it is easier to find the required information

Question Answer Marks

2 Four from: 4

When a file is written to the disk, it can be automatically encrypted by

encryption software
Full disk encryption is when the data is encrypted as soon as it is saved to the
hard disk
When a file is read from the disk the decryption/encryption key/password is
needed to decrypt it
When a file is read from the disk, the software automatically decrypts it…
… while in some types of hard disk encryption leaving all other data on the
disk encrypted
(All) the files on the disk are encrypted/ It’s the encryption of data on that
disk…
…except in some cases the operating system
Whether the disk stays in the computer or moved to another computer it is still
encrypted
Only the person/computer with the secret/decryption/encryption key/password
can understand the data on the disk/data can’t be read without the
decryption/encryption key/unauthorised people cannot read the data

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Question Answer Marks

3(a) Four from: 4

For even parity:

Three max from

When data is transmitted the sending device/computer counts the number of
ones in each byte
Each byte is checked individually
The parity bit is used to make sure the number of ones is even
If the number of ones is even it sets the parity bit to 0 (and adds this on to the
end of the byte)
If the number of ones is odd it sets the parity bit to 1 (before adding it on)
Every byte of data should have an even number of ones
The receiving device/computer checks each byte to make sure that it has an
even number of ones
If the number of ones is odd there has been an error during the transfer of
data

Two max from

In this example data is not being transferred from one device to another/data
is not being transmitted
She is only entering data to the computer so will need to use an alternative
verification method

Accept answers which are odd parity answers (substitute odd for even
in points above)

3(b) Four from 4

Similarities
Both involve comparing data that has been/is being entered with another copy
Both involve checking that data has been entered correctly not that it is
correct/pick up errors made during data entry

Differences
Visual verification is carried out by a human/user/yourself
Double data entry is carried out by the computer/ computerised
Visual verification involves comparing the entered data with the original
source
Double data entry involves comparing two versions of the entered data
Visual verification will enable the user to see mistakes if they have been made
With double data entry computer will alert user to the fact that a mistake has
been made and they decide which version has been copied correctly/freezes
keyboard to prevent data being entered until error is corrected

Must have at least one similarity and one difference to gain full marks

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Question Answer Marks

4 Six from: 6
Similarities
Both are used to measure performance speeds of computers/processors
Both can be unreliable as the complexity of instructions can vary according to
which benchmark program/test is used/complex instruction takes longer to
process than a simple one

Differences
MIPS are used with mainframes
(M)FLOPS used with supercomputers
MIPS can be used with integers
(M)FLOPS with real/floating point numbers
MIPS measured in millions
(M)FLOPS measured in quadrillions and higher
MIPs is millions of instructions per second, FLOPs is floating point operations
per second (must have both)
MIPS used when measuring performance of computers involved in running
application software…
…whereas FLOPS used where scientific/complex calculations need to be
carried out
MIPS do not take into account input/output speeds…
… whereas FLOPS do not take into account CPU’s clock speed , bus speed,
the amount of RAM available

Must have at least one similarity and difference to gain full marks

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Question Answer Marks

5 Eight from: 8

Advantages
Once it is compiled a program does not have to be translated again
A compiled program can run faster than interpreted software
Compiling a program is a much quicker process /translates it faster than
interpreting…
… as whole program is translated all in one go /all at once …
…unlike interpreter translates one line at a time
Once the program is already compiled into machine language, there is no
translation software that the user has to keep up to date
Compilers also improve security for programmers…
…makes it much harder to copy code/machine code is difficult to understand
and alter…
…so fewer risks of copyright infringement…
… with an interpreted program, the source code can always be seen so
greater risk of software copyright infringement

Disadvantages
Can only be used on one operating system
… source code can be interpreted on any operating system provided
interpreter is present…
…will need to use an interpreter if program is to be shared…
It is slow/(more) difficult to debug the program/find errors…
…the whole program needs to be compiled again after an error is corrected…
…error messages are output at the end…
…whereas with an interpreter error messages are output as they are found
It uses up more memory than an interpreter…
…as whole program has to be loaded…
…interpreter only requires a few statements of the program to be in memory
Unlike an interpreter, does not allow small pieces of code to be tested to
make sure they work before continuing with the rest of the program
More likely to crash the computer as it is running directly on the CPU

Must have at least two of each to gain full marks

Must be a proper discussion to obtain full marks
Max. six marks if bullets/list of points
Must have expansions or comparisons to be a proper discussion

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Question Answer Marks

6(a) Humidity sensor combination of moisture sensor and temperature 4

sensor/measures how much moisture is in atmosphere together with
temperature – 1 mark
Used in weather stations to measure relative/absolute humidity /air humidity
/any suitable example – 1 mark

Sound sensor converts sound waves into voltages/electrical signals – 1 mark

Used in environment monitoring systems to measure noise pollution /any
suitable example – 1 mark

6(b) Two from: 2

The accuracy of all sensors reduces after a period of time...

...due to constant use in/exposure to the atmosphere/liquids that are being
used
Regular calibration helps to maintain the accuracy of the sensors/helps to
make sure sensors produce accurate/correct/reliable readings
Other devices within a monitoring system may deteriorate over time resulting
in a need for recalibration

6(c) Five from: 5

Only one measurement point/reading with one point calibration whereas with
two point calibration at least two readings are taken
One point calibration is appropriate for sensors used to measure a value that
is constant/never changes…
…whereas two-point calibration is used with sensors that measure a
constantly changing variable
With one point calibration the offset only is calculated/ the sensor reading is
subtracted from the known value only…
…the offset is then added to every subsequent reading
With two point calibration sensitivity needs to be included not just an offset
Two point calibration is used where there is a linear relationship between the
two readings
The slope of the line connecting the two readings is compared with the slope
of the line of the pre-calibrated sensor/the range values of the sensor is
compared with the range values for the standard
Two point calibration compensates for both offset errors and sensitivity/slope
errors

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Question Answer Marks

7 7
Start

count ← 0
max ← 0

Input
number

Is no
number
<= max?

max ← number
yes

count ← count + 1
Is number <= max in 1st decision
box – 1 mark
Yes/no in correct positions at 1st
decision box – 1 mark
no
Is count = max ← number in correct box – 1
10?
mark
increment count in correct box – 1
yes mark
is count = 10? in 2nd decision box –
Print max
1 mark
yes/no in correct positions at 2nd
decision box – 1 mark
Print max in correct box – 1 mark
Stop

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Question Answer Marks

8(a) Four from: 4

Hacker creates a fake website which looks like the actual bank’s
website/legitimate-looking website
Fools the user into thinking they have gone to the correct website/have not
been re-directed
Hacker installs a piece of malicious software/code on customer’s computer/
user downloads a piece of malicious software/code without realising it
Software corrupts the Hosts file on the user’s computer
Software adds the URLs of banks together with IP address of the fake website
Fraudster redirects genuine website’s traffic to own website/ when user enters
a bank’s URL they are redirected to hacker’s website …
…user is now sending personal details to fraudster’s website unknowingly /
website asks customer to enter banking information/hacker gains personal
information from website /customer types in personal details on website
Hacker uses the acquired information from the website to log on to the user’s
bank account/make purchases/commit identity theft/withdraw cash

8(b) Three from: 3

Use up to date anti-virus software to prevent the downloading of malicious

software
Use firewalls to prevent malicious software entering the computer
Use trusted DNS servers / don’t enter personal data into sites without https
The latest browsers alert users when a fake website has been loaded/users
need to use the latest browser software updates
Use a trusted, legitimate Internet Service Provider
Check the digital certificate to make sure the site is legitimate
Be suspicious and careful not to use websites which contain poor grammar or
spelling
Avoid using public Wi-fi systems

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Question Answer Marks

9(a) READ first record in transaction file 6

READ first record in old master file
WHILE not end of transaction file
IF transaction file WorkerID = master file WorkerID
THEN
WagesSoFar ← WagesSoFar + (RateOfPay*HoursWorked)
WRITE updated master file record to new master file
READ next record in transaction file
ENDIF
READ next record in master file
ENDWHILE

Six from:

Correct calculation – RateOfPay*HoursWorked - 1 mark

Correct calculation - WagesSoFar ← WagesSoFar +
(RateOfPay*HoursWorked) – 1 mark
Correct update – 1 mark
Read next transaction file record… – 1 mark
…immediately before ENDIF – 1 mark
ENDIF– 1 mark
Read next master file record… – 1 mark
… immediately after ENDIF – 1 mark
ENDWHILE at end of algorithm – 1 mark

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Question Answer Marks

9(b) Eight from: 8

Advantages
Batch processing does not require constant use of the computer when it might
be needed for other tasks...
...the payroll only needs to be run at the end of the week/month…
…whereas real time processing would require computer to be available all the
time…
…batch processing/payroll can be run at convenient times for the
company/when the computing resources are less busy/when there is little
demand for computer resources/can be run overnight
Real-time processing requires immediate processing of data which is
unnecessary with payroll...
...as hours worked would only be known at the end of each day so no point in
using real-time processing
Real-time processing is not usually capable of processing large volumes of
data such as running a payroll whereas batch processing is
Batch processing systems only need lower specification computers…
…whereas real-time processing needs more complex computer systems
Online processing requires more hardware making it more expensive than
batch processing
Batch processing only needs a few employees to enter the data…
…so total wage bill is less…
…whereas online processing systems can need employees to be constantly
using the system
In batch processing systems there are fewer/no transcription/update/data
errors…
…than human operators would produce in an online system

Disadvantages
With batch processing there is a time delay between collecting the input data
and getting an output/data is not processed until the time specified
With batch processing the information is only up to date after the master file
has been updated by the transaction file…
…whereas in real-time processing information is always up to date
With batch processing systems errors are only revealed during
processing/after batch process is complete which can be overnight and so
cause delays/errors cannot be corrected until the batch process is complete…
…in online processing errors are revealed, and can be acted upon,
immediately
Users cannot terminate a process during execution/have to wait until
execution is completed

Must have at least two of each to gain full marks

Must be a proper discussion to obtain full marks
Max. six marks if bullets/list of points
Must have expansions or comparisons to be a proper discussion

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