CAMBRIDGE IGCSE COMPUTER
SCIENCE 0948/0478 SYLLABUS FOR
2024/2025 EXAM REVIEW QUESTIONS
WITH COMPLETE SOLUTIONS
What is full-duplex transmission? - Answer-where data can travel in both directions
simulataneously using two cables
3 advantages of serial over parallel - Answer-- cheaper
- more reliable
- quicker
What is the USB used for - Answer-Universal Serial Bus - a type of cable and connector
commonly used for half-duplex or full-duplex serial data transmission between a
computer and attached devices.
Why can errors occur after data transmission - Answer-due to interference such as data
loss, data gain and data change
What is a checksum? - Answer-the checksum of all bytes in a data transmission is
calculated using an algorithm, checksum is sent with data then the recieving computer
recalculates the checksum and compares it. If it does not match data has been altered
What is an echo check - Answer-the recieving computer sends a copy of the data back
to the sending computer for comparison. The sending computer compares both data
sets to see if any errors have occured. If they have data will be resent
What is a check digit? - Answer-When transmitting data , errors may occur and some
data may be incorrectly received. To overcome this, an extra value is transmitted to help
determine if the data received is correct or incorrect. This value is known as a check
digit.
What is an ARQ - Answer-automatic repeat query - A form of error detection using
acknowledgements and timeouts. If a receiving device doesn't send an
acknowledgement back to the sending device before the timeout occurs, the data will be
sent again automatically.
What is encryption? - Answer-Encryption is the process of encoding data or a message
so that it cannot be understood by anyone other than its intended recipient.
, How is data encrypted using symmetric encryption - Answer-Symmetric encryption uses
one key to encrypt and decrypt. If you encrypt a file, and then decrypt with the same
key, you are using symmetric encryption.
How is data encrypted using asymmetric encryption - Answer-Asymmetric encryption
uses a mathematically related pair of keys for encryption and decryption: a public key
and a private key. If the public key is used for encryption, then the related private key is
used for decryption. If the private key is used for encryption, then the related public key
is used for decryption.
What is the cpu in a computer - Answer-the central processing unit processes
instructions that are input into the computer so that the result can be output
What is a microprocessor? - Answer-a type of intergrated circuit on a single chip
What is Von Neumann architecture? - Answer-A system where the CPU runs programs
stored in memory
- data and instructions are both stored as binary digits in primary memory
- instructions are fetched from memory one at a time and in order
- the processor decodes and executes an instruction, before cycling around to fetch the
next instruction
- the cycle continues until no more instructions are available
What is the ALU - Answer-Arithmetic logic unit - component of CPU that performs
arithmetic/logical operations
What is the CU - Answer-control unit - fetch, executes and decodes instructions and
sends control signals
What is the PC - Answer-Program Counter - Holds the address of the next instruction to
be executed
What is the MAR - Answer-Memory address register and holds any memory address
about to be used by the CPU
What is the MDR - Answer-Memory Data Register - Holds the actual data or instruction
What is the CIR - Answer-current instruction register - holds the instruction that is
currently being decoded and executed
What is the ACC - Answer-Accumulator - holds the data being processed and the
results of processing
SCIENCE 0948/0478 SYLLABUS FOR
2024/2025 EXAM REVIEW QUESTIONS
WITH COMPLETE SOLUTIONS
What is full-duplex transmission? - Answer-where data can travel in both directions
simulataneously using two cables
3 advantages of serial over parallel - Answer-- cheaper
- more reliable
- quicker
What is the USB used for - Answer-Universal Serial Bus - a type of cable and connector
commonly used for half-duplex or full-duplex serial data transmission between a
computer and attached devices.
Why can errors occur after data transmission - Answer-due to interference such as data
loss, data gain and data change
What is a checksum? - Answer-the checksum of all bytes in a data transmission is
calculated using an algorithm, checksum is sent with data then the recieving computer
recalculates the checksum and compares it. If it does not match data has been altered
What is an echo check - Answer-the recieving computer sends a copy of the data back
to the sending computer for comparison. The sending computer compares both data
sets to see if any errors have occured. If they have data will be resent
What is a check digit? - Answer-When transmitting data , errors may occur and some
data may be incorrectly received. To overcome this, an extra value is transmitted to help
determine if the data received is correct or incorrect. This value is known as a check
digit.
What is an ARQ - Answer-automatic repeat query - A form of error detection using
acknowledgements and timeouts. If a receiving device doesn't send an
acknowledgement back to the sending device before the timeout occurs, the data will be
sent again automatically.
What is encryption? - Answer-Encryption is the process of encoding data or a message
so that it cannot be understood by anyone other than its intended recipient.
, How is data encrypted using symmetric encryption - Answer-Symmetric encryption uses
one key to encrypt and decrypt. If you encrypt a file, and then decrypt with the same
key, you are using symmetric encryption.
How is data encrypted using asymmetric encryption - Answer-Asymmetric encryption
uses a mathematically related pair of keys for encryption and decryption: a public key
and a private key. If the public key is used for encryption, then the related private key is
used for decryption. If the private key is used for encryption, then the related public key
is used for decryption.
What is the cpu in a computer - Answer-the central processing unit processes
instructions that are input into the computer so that the result can be output
What is a microprocessor? - Answer-a type of intergrated circuit on a single chip
What is Von Neumann architecture? - Answer-A system where the CPU runs programs
stored in memory
- data and instructions are both stored as binary digits in primary memory
- instructions are fetched from memory one at a time and in order
- the processor decodes and executes an instruction, before cycling around to fetch the
next instruction
- the cycle continues until no more instructions are available
What is the ALU - Answer-Arithmetic logic unit - component of CPU that performs
arithmetic/logical operations
What is the CU - Answer-control unit - fetch, executes and decodes instructions and
sends control signals
What is the PC - Answer-Program Counter - Holds the address of the next instruction to
be executed
What is the MAR - Answer-Memory address register and holds any memory address
about to be used by the CPU
What is the MDR - Answer-Memory Data Register - Holds the actual data or instruction
What is the CIR - Answer-current instruction register - holds the instruction that is
currently being decoded and executed
What is the ACC - Answer-Accumulator - holds the data being processed and the
results of processing
