1A Answer
1B answer
1C answer
Derivation of the required ASCII code:
Derive the fact that 74 denary is the ASCII value for the letter ‘J’ (1)
Example:
D, E, F, G, H, I, J == 68, 69, 70, 71, 72, 73, 74
J – D = 6; 68 + 6 = 74
More help here - Ascii explained
Derive the fact that 74 denary is the ASCII value for the letter ‘J’ (1)
Example:
D, E, F, G, H, I, J == 68, 69, 70, 71, 72, 73, 74
J – D = 6; 68 + 6 = 74
More help here - Ascii explained
1di answer
Calculation:
• 1 kilobyte = 1024 bytes (1)
• 3 x 1024 or 3072 (1)
More help here - Converting between byte sizes
• 1 kilobyte = 1024 bytes (1)
• 3 x 1024 or 3072 (1)
More help here - Converting between byte sizes
1dii answer
Calculation:
1 Megabit = 1,000,000 bits(1)
3 x 1,000,000 or 3,000,000 (1)
More help here -
1 Megabit = 1,000,000 bits(1)
3 x 1,000,000 or 3,000,000 (1)
More help here -
1e answer
1f answer
A description that makes reference to the following points:
• A client uses the address of the server to make a connection (1)
• then the client sends a request to the server/client request services from the server (1)
• The server obtains the address of the client once that client makes a connection to the server (1)
• then the server sends the requested data/services (to the client) (1)
More help here - Client server model
• A client uses the address of the server to make a connection (1)
• then the client sends a request to the server/client request services from the server (1)
• The server obtains the address of the client once that client makes a connection to the server (1)
• then the server sends the requested data/services (to the client) (1)
More help here - Client server model
1g answer
2A answer
An explanation that makes reference to the following points:
• lossless compression ensures that no data is lost (1)
• so that the desktop published file can be restored so that it is exactly the same as the original (1)
More help here - Compression explained
• lossless compression ensures that no data is lost (1)
• so that the desktop published file can be restored so that it is exactly the same as the original (1)
More help here - Compression explained
2B answer
Any two from:
• Data is removed during the compression process (1)
• The removed data is not normally noticed by a human (sight, sound) (1)
• The original contents of the file cannot be restored exactly (1)
More help here - Lossy compression
• Data is removed during the compression process (1)
• The removed data is not normally noticed by a human (sight, sound) (1)
• The original contents of the file cannot be restored exactly (1)
More help here - Lossy compression
2c answer
• Letters in correct order (1)
• Correct number (1)
Either: 3b 1r 4g 2r
Or
b3 r1 g4 r2
More help here - RLE explained
• Correct number (1)
Either: 3b 1r 4g 2r
Or
b3 r1 g4 r2
More help here - RLE explained
3a answer
An explanation that makes reference to two of the following points:
• Defragmentation software moves file blocks closer together (1)
• Compression software reduces file sizes using less space (1)
• Use backup software to move files to a secure place and deleting files on the hard disc frees up space (1)
and
• this speeds up disc access times to the files (which will improve the speed of the disc) (1)
More help here - Utility software
• Defragmentation software moves file blocks closer together (1)
• Compression software reduces file sizes using less space (1)
• Use backup software to move files to a secure place and deleting files on the hard disc frees up space (1)
and
• this speeds up disc access times to the files (which will improve the speed of the disc) (1)
More help here - Utility software
3b answer
Any two reasons from:
• Instructions are close to English/easier for humans to read/write than a low-level language/makes fewer errors (1)
• It’s quicker to develop code/easier to maintain code (than if it were written in a low-level language) (1)
• They are usually available across many platforms/chipsets/operating systems (1)
More help here - High level languages
• Instructions are close to English/easier for humans to read/write than a low-level language/makes fewer errors (1)
• It’s quicker to develop code/easier to maintain code (than if it were written in a low-level language) (1)
• They are usually available across many platforms/chipsets/operating systems (1)
More help here - High level languages
3c answer
An explanation that makes reference to the following point:
• Intellectual property can be protected by copyright/patent laws (1)
Plus one from:
• so that by registering the patent the patent holder has exclusive rights to make/use/sell the software (1)
• so that by registering the copyright the source/(object) code is protected (1)
More help here - IP
• Intellectual property can be protected by copyright/patent laws (1)
Plus one from:
• so that by registering the patent the patent holder has exclusive rights to make/use/sell the software (1)
• so that by registering the copyright the source/(object) code is protected (1)
More help here - IP
3d answer
Indicative content:
• are written only once/no repeated/copied blocks of code (1)
• only needs to be debugged once (1)
• can be reused/called from anywhere in the program (1)
• make main program more readable/shorter (1)
• can reduce the need for global variables (1)
• can be put into libraries/reused in other programs/shared with others (1)
• can be used to hide complex code/functionality (1)
• can be written in low-level languages for special purpose/interact with hardware/optimise performance (1)
More help here - subprograms
• are written only once/no repeated/copied blocks of code (1)
• only needs to be debugged once (1)
• can be reused/called from anywhere in the program (1)
• make main program more readable/shorter (1)
• can reduce the need for global variables (1)
• can be put into libraries/reused in other programs/shared with others (1)
• can be used to hide complex code/functionality (1)
• can be written in low-level languages for special purpose/interact with hardware/optimise performance (1)
More help here - subprograms
4a answer
A description that makes reference to the following points:
• the protocol allows the devices on a network to communicate with each other (1)
• by the use of a common set of rules (1)
More help here - Protocols
• the protocol allows the devices on a network to communicate with each other (1)
• by the use of a common set of rules (1)
More help here - Protocols
4b answer
An explanation that makes reference to the following points:
• A patch will fix any known security issues (1)
• so the machine running the application is less vulnerable to successful cyberattacks (1)
More help here - Patch
• A patch will fix any known security issues (1)
• so the machine running the application is less vulnerable to successful cyberattacks (1)
More help here - Patch
4c answer
A description that makes reference to the following points:
• device B puts the address of device C into a packet/message to send (1)
• then device A reads that address and sends the packet to device C (1)
• device B puts the address of device C into a packet/message to send (1)
• then device A reads that address and sends the packet to device C (1)
4d answer
Indicative content:
• The school/technical team will be responsible for backing up/disaster recovery if the data is stored on hard discs (connected to the school's servers)
• The storage provider is responsible for backup/disaster recovery if the school stores its data in the 'cloud'
• The school's files are available without an internet connection if data is stored on hard discs (connected to the school's servers)
• An internet connection is required to access the school's files if they are stored in the 'cloud'
• Staff at the school can access their files anywhere by using mobile devices if the school's files are stored in the 'cloud'
• The staff can access their files at school only if the data is stored on hard discs (connected to the school's servers)
• The school will be responsible for maintaining the servers, replacing them when they age/technology becomes outdated
• The storage provider is responsible for updating the storage system in the cloud and providing new technology as it evolves
• The school will be responsible for increasing the storage capacity of their servers as demands evolve
• The storage provider is able to provide additional storage space on demand.
More help here - Cloud vs Servers
• The school/technical team will be responsible for backing up/disaster recovery if the data is stored on hard discs (connected to the school's servers)
• The storage provider is responsible for backup/disaster recovery if the school stores its data in the 'cloud'
• The school's files are available without an internet connection if data is stored on hard discs (connected to the school's servers)
• An internet connection is required to access the school's files if they are stored in the 'cloud'
• Staff at the school can access their files anywhere by using mobile devices if the school's files are stored in the 'cloud'
• The staff can access their files at school only if the data is stored on hard discs (connected to the school's servers)
• The school will be responsible for maintaining the servers, replacing them when they age/technology becomes outdated
• The storage provider is responsible for updating the storage system in the cloud and providing new technology as it evolves
• The school will be responsible for increasing the storage capacity of their servers as demands evolve
• The storage provider is able to provide additional storage space on demand.
More help here - Cloud vs Servers
5a answer
An explanation that makes reference to the following points:
• monitors weight of load (1)
• so that it can adjust water levels for small/large loads (1)
OR
• monitors water temperature (1)
• so it can maintain the required value by turning heating element on/off (1)
OR
• monitors soaking button setting (1)
• so that it can add additional time at the right place in the programme cycle (1)
OR
• monitors maximum spin switch setting (1)
• so that it can set required motor revolutions (1)
More help here - Embedded systems
• monitors weight of load (1)
• so that it can adjust water levels for small/large loads (1)
OR
• monitors water temperature (1)
• so it can maintain the required value by turning heating element on/off (1)
OR
• monitors soaking button setting (1)
• so that it can add additional time at the right place in the programme cycle (1)
OR
• monitors maximum spin switch setting (1)
• so that it can set required motor revolutions (1)
More help here - Embedded systems
5b answer
A truth table for the function of the operator AND:
• four different input combinations and four different correct output combinations
False AND False = False
False AND True = False
True AND False = False
True AND True = True
More help here - Logic gates
• four different input combinations and four different correct output combinations
False AND False = False
False AND True = False
True AND False = False
True AND True = True
More help here - Logic gates
5c answer
A logic statement that includes:
• Correct use of ‘OR’ (1)
• Correct use of ‘AND’ (1)
• Correct use of brackets or order of precedence if brackets not used (1)
Examples:
• (O OR M) AND P
• P AND (M OR O)
• (O AND P) OR (P AND M)
• O AND P OR P AND M
More help here - Logical statements
• Correct use of ‘OR’ (1)
• Correct use of ‘AND’ (1)
• Correct use of brackets or order of precedence if brackets not used (1)
Examples:
• (O OR M) AND P
• P AND (M OR O)
• (O AND P) OR (P AND M)
• O AND P OR P AND M
More help here - Logical statements
5d answer
6a answer
A statement that includes:
• an algorithm is a sequence of steps/step-by-step instructions (1)
• which (if followed exactly) will perform a specific task (1)
More help here - Algorithm
• an algorithm is a sequence of steps/step-by-step instructions (1)
• which (if followed exactly) will perform a specific task (1)
More help here - Algorithm
6b answer
Two reasons:
• Encrypted data is encoded/scrambled so that it cannot be understood (1)
• The unauthorised person would not have the key to decrypt the data (1)
More help here - Encryption
• Encrypted data is encoded/scrambled so that it cannot be understood (1)
• The unauthorised person would not have the key to decrypt the data (1)
More help here - Encryption
6c answer
• Applying a double shift to ‘pink’ to obtain unsp (1)
• Identifying +5 as the equivalent single shift to obtain unsp (1)
• Recognise that both shifts give the same result, so the double shift is no more secure than the single shift (1)
More help here - Caesar cipher explained
• Identifying +5 as the equivalent single shift to obtain unsp (1)
• Recognise that both shifts give the same result, so the double shift is no more secure than the single shift (1)
More help here - Caesar cipher explained
6di answer
A statement that includes:
• a pixel is the smallest identifiable unit in a graphic image (1)
More help here - Pixel explained
• a pixel is the smallest identifiable unit in a graphic image (1)
More help here - Pixel explained
6dii answer
• Mathematical expression (1)
• 15000 bytes (1)
Example:
300 ×100 ×4
_______________ = 15000
8
More help here - Image size
• 15000 bytes (1)
Example:
300 ×100 ×4
_______________ = 15000
8
More help here - Image size
6e answer
6f answer
An explanation that makes reference to the following points:
• The set-top box must process data quickly (1)
• so a compiler is used because compiled code runs faster than interpreted code (1)
More help here - Compiler vs Interpreter
• The set-top box must process data quickly (1)
• so a compiler is used because compiled code runs faster than interpreted code (1)
More help here - Compiler vs Interpreter
6g answer
A statement that includes:
• (Abstracting means) removing unnecessary detail/simplifying (1)
• so that we can focus on the essence/real part/important part of the problem (1)
More help here - Abstraction
• (Abstracting means) removing unnecessary detail/simplifying (1)
• so that we can focus on the essence/real part/important part of the problem (1)
More help here - Abstraction
6hi answer
A statement that includes:
• The purpose of ‘roll’ is to generate a single number, chosen randomly, between 1 and 12, inclusive (1)
OR
• Two numbers between 1 and 6
More help here - Algorithm
• The purpose of ‘roll’ is to generate a single number, chosen randomly, between 1 and 12, inclusive (1)
OR
• Two numbers between 1 and 6
More help here - Algorithm
6hii answer
One of the following reasons:
• ‘Roll’ is an abstraction because it allows the programmer to focus on the result of a roll, rather than on how to implement the roll algorithm (1)
OR
• ‘Roll’ is an abstraction because it is a model/simulation/representation of a real/physical activity/action (1)
More help here - Abstraction
• ‘Roll’ is an abstraction because it allows the programmer to focus on the result of a roll, rather than on how to implement the roll algorithm (1)
OR
• ‘Roll’ is an abstraction because it is a model/simulation/representation of a real/physical activity/action (1)
More help here - Abstraction
7ai answer
7aii answer
The comparison should include reference to both two’s complement and signed magnitude numbers for any two of the following:
• Addition of two’s complement will always work (1)
• Addition of sign-magnitude numbers does not always work (1)
• There is only one way to represent the number 0 in two’s complement (1)
• There are two ways to represent the number 0 in sign-magnitude numbers (1)
More help here - Comparison
• Addition of two’s complement will always work (1)
• Addition of sign-magnitude numbers does not always work (1)
• There is only one way to represent the number 0 in two’s complement (1)
• There are two ways to represent the number 0 in sign-magnitude numbers (1)
More help here - Comparison
7aiii answer
7Bi answer
Correct identification of the labelled items:
A. Analogue signal/sound wave (1)
B. Sample interval (1)
C. Amplitude (1)
More help here - Digital sound
A. Analogue signal/sound wave (1)
B. Sample interval (1)
C. Amplitude (1)
More help here - Digital sound
7Bii answer
An explanation that makes reference to the following points:
• (Higher sampling frequencies) generate more sampling data (1)
• which increases memory/storage requirements (1)
• and gives a more accurate digital representation (of the original signal) (1)
More help here - Sampling
• (Higher sampling frequencies) generate more sampling data (1)
• which increases memory/storage requirements (1)
• and gives a more accurate digital representation (of the original signal) (1)
More help here - Sampling