Learn Extracted exam questions A-Level Computer Science 9618 Computer Science June 2025 Question Paper 12
9618 Computer Science June 2025 Question Paper 12
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The table has six statements about the Von Neumann model for a computer system. Three of the statements are incorrect.
\begin{tabular}{|c|l|} \hline \textbf{Statement number} & \textbf{Statement} \ \hline 1 & The Program Counter (PC) stores the next instruction to be fetched from memory. \ \hline 2 & The Arithmetic and Logic Unit (ALU) performs mathematical and logical operations. \ \hline 3 & The Control Unit (CU) sends signals to other components on the data bus. \ \hline 4 & The Memory Data Register (MDR) transfers data to the memory address stored in the Memory Address Register (MAR). \ \hline 5 & The MAR stores an address from memory. \ \hline 6 & The Accumulator (ACC) stores the result of calculations. \ \hline \end{tabular}
Complete the table by writing the \textbf{three} incorrect statement numbers and the corrected statements.
\begin{tabular}{|c|l|} \hline \textbf{Incorrect statement number} & \textbf{Corrected statement} \ \hline & \ \hrulefill & \hrulefill \ & \hrulefill \ & \hrulefill \ \hline & \ \hrulefill & \hrulefill \ & \hrulefill \ & \hrulefill \ \hline & \ \hrulefill & \hrulefill \ & \hrulefill \ & \hrulefill \ \hline \end{tabular}
Registers that are used in the Fetch-Execute (F-E) cycle include the PC, MAR, MDR and the ACC.
Identify \textbf{one} other register and describe its role in the Fetch-Execute (F-E) cycle.
Register \hrulefill
Role
Explain how an interrupt from an input device will be detected and handled in the F-E cycle.
Convert the denary integer 558 into 12-bit binary and hexadecimal.
Binary \hrulefill Hexadecimal \hrulefill
Convert the two's complement binary integer 11100010 into denary.
Write the smallest and the largest two's complement binary integers that can be represented in 8 bits.
Smallest \hrulefill Largest \hrulefill
Give \textbf{one} application where Binary Coded Decimal (BCD) is used and justify its use.
Application \hrulefill Justification \hrulefill
A computer program uses a digital camera to read the words on an item.
The program can read the words that are written on the item, translate the words to a chosen language and then output the words as audio. For example, when used in a supermarket, the program can output the words written on the labels on products.
The program uses Artificial Intelligence (AI).
Explain how AI is used in the computer program described.
State \textbf{two} social benefits of the use of AI in the computer program described.
- \hrulefill
- \hrulefill
The computer program is released under a commercial software licence.
Describe the features of a commercial software licence.
Explain the reasons why an open source software licence might not be appropriate for the computer program described.
Write the logic expressions for the following logic circuit.
X = \hrulefill Y = \hrulefill
Complete the truth table for the logic expression:
\begin{tabular}{|c|c|c|c|c|} \hline \textbf{A} & \textbf{B} & \textbf{C} & \textbf{Working space} & \textbf{X} \ \hline 0 & 0 & 0 & & \ \hline 0 & 0 & 1 & & \ \hline 0 & 1 & 0 & & \ \hline 0 & 1 & 1 & & \ \hline 1 & 0 & 0 & & \ \hline 1 & 0 & 1 & & \ \hline 1 & 1 & 0 & & \ \hline 1 & 1 & 1 & & \ \hline \end{tabular}
An online game has a database that stores data about users and the characters each user creates in the game. Each user can create multiple characters and purchase multiple items for each character.
The normalised database has the following design:
\texttt{USER(Username, Password, DateOfBirth)}
\texttt{CHARACTER(CharacterName, CharacterID, Username, Level, Money)}
\texttt{ITEM(ItemName, MinimumLevel, Cost)}
\texttt{CHARACTER_ITEM(CharacterID, ItemName)}
Explain the purpose of the table \texttt{CHARACTER_ITEM} in the database.
Underline the attribute, or attributes, that form the primary key in each of the tables.
\texttt{USER(Username, Password, DateOfBirth)}
\texttt{CHARACTER(CharacterName, CharacterID, Username, Level, Money)}
\texttt{ITEM(ItemName, MinimumLevel, Cost)}
\texttt{CHARACTER_ITEM(CharacterID, ItemName)}
A Database Management System (DBMS) provides data security.
Identify \textbf{two} methods the DBMS can use to protect the data in the table \texttt{USER} from unauthorised access.
Explain how each method protects the data.
The DBMS also supports data integrity.
Give \textbf{two} ways that a DBMS can support data integrity.
- \hrulefill
- \hrulefill
Write a Structured Query Language (SQL) script to count the number of items purchased by the user with the username "KAT123".
The following changes need to be made to the character with the ID "0002":
\begin{itemize} \item level changed to 3 \item money changed to 10000.00 \end{itemize}
Write an SQL script to change the character’s data.
A company has multiple sites in different cities. The company has drivers who deliver products to customers. Each driver can connect to the company's WAN (Wide Area Network) whilst out of the office using a smartphone.
State \textbf{two} ways that a WAN is different to a LAN (Local Area Network).
- \hrulefill
- \hrulefill
The smartphones use the cell phone network to connect to the WAN.
Explain how data is transmitted using the cell phone network.
Devices that connect to the WAN have an IP address.
Complete the following description of IP addresses by writing the missing words.
IPv4 is displayed as four groups of 8-bit numbers separated by \underline{\hspace{1.5em}}.
Each IPv4 address is 32 bits.
IPv6 is made of eight groups of 4 \underline{\hspace{1.5em}} numbers separated by colons.
Multiple consecutive groups of \underline{\hspace{1.5em}} can be replaced with a double colon.
Each IPv6 address is \underline{\hspace{1.5em}} bits.
A \underline{\hspace{1.5em}} IP address can change each time the computer connects to a network.
A \underline{\hspace{1.5em}} IP address can only be accessed by other devices in the same LAN and is assigned by the router within the LAN.
The main office for the company has four wired computers, one server, two printers, one central switch and a device providing a single point of access for the internet. The network is set up as a star topology.
Draw the topology for the main office network. Label all devices.
Describe the role of a switch in a network.
The following table shows part of the instruction set for a processor. The processor has one register: the Accumulator (ACC).
\begin{tabular}{|l|l|l|} \hline \multicolumn{2}{|c|}{\textbf{Instruction}} & \multicolumn{1}{c|}{\textbf{Explanation}} \ \hline \textbf{Opcode} & \textbf{Operand} & \ \hline LDD &
& Direct addressing. Load the contents of the location at the given address to ACC \ \hline LDM & #n & Immediate addressing. Load the number n to ACC \ \hline STO & & Store the contents of ACC at the given address \ \hline ADD & #n/Bn/&n & Add the number n to the ACC \ \hline ADD & & Add the contents of the given address to the ACC \ \hline INC &ACC denotes Accumulator
can be an absolute or a symbolic address \# denotes a denary number, e.g. \#123 B denotes a binary number, e.g. B01001010 \& denotes a hexadecimal number, e.g. \&4AThe current contents of memory are:
\begin{tabular}{r|l|} \cline{2-2} \textbf{10} & 12 \ \cline{2-2} \textbf{11} & 11 \ \cline{2-2} \textbf{12} & 10 \ \cline{2-2} \textbf{13} & 22 \ \cline{2-2} \textbf{14} & 22 \ \cline{2-2} ... & \ \cline{2-2} \textbf{100} & LDD 10 \ \cline{2-2} \textbf{101} & ADD 12 \ \cline{2-2} \textbf{102} & STO 11 \ \cline{2-2} \textbf{103} & CMP 14 \ \cline{2-2} \textbf{104} & JPE 107 \ \cline{2-2} \textbf{105} & INC ACC \ \cline{2-2} \textbf{106} & JMP 101 \ \cline{2-2} \textbf{107} & STO 10 \ \cline{2-2} \textbf{108} & END \ \cline{2-2} \end{tabular}
Trace the program currently in memory using the following trace table.
\begin{tabular}{|c|c|c|c|c|c|c|} \hline \multirow{2}{}{\textbf{Instruction address}} & \multirow{2}{}{\textbf{ACC}} & \multicolumn{5}{c|}{\textbf{Memory address}} \ \cline{3-7} & & \textbf{10} & \textbf{11} & \textbf{12} & \textbf{13} & \textbf{14} \ \hline & & 12 & 11 & 10 & 22 & 22 \ \hline & & & & & & \ \hline & & & & & & \ \hline & & & & & & \ \hline & & & & & & \ \hline & & & & & & \ \hline & & & & & & \ \hline & & & & & & \ \hline & & & & & & \ \hline & & & & & & \ \hline \end{tabular}
State the effect of changing instruction \texttt{LDD 10} in address 100 to \texttt{LDM #10}
Identify \textbf{and} describe \textbf{one} mode of addressing \textbf{not} given in the table of instructions in part (a).
Mode of addressing \hrulefill
Description
The table shows part of the instruction set for a processor. The processor has one register: the Accumulator (ACC).
\begin{tabular}{|c|l|l|} \hline \multicolumn{2}{|c|}{\textbf{Instruction}} & \multicolumn{1}{c|}{\textbf{Explanation}} \ \cline{1-2} \textbf{Opcode} & \multicolumn{1}{c|}{\textbf{Operand}} & \ \hline \texttt{AND} & \texttt{#n/Bn/&n} & Bitwise AND operation of the contents of ACC with the operand \ \hline \texttt{AND} & \texttt{
} & Bitwise AND operation of the contents of ACC with the contents of \texttt{} \ \hline \texttt{XOR} & \texttt{#n/Bn/&n} & Bitwise XOR operation of the contents of ACC with the operand \ \hline \texttt{XOR} & \texttt{} & Bitwise XOR operation of the contents of ACC with the contents of \texttt{} \ \hline \texttt{OR} & \texttt{#n/Bn/&n} & Bitwise OR operation of the contents of ACC with the operand \ \hline \texttt{OR} & \texttt{} & Bitwise OR operation of the contents of ACC with the contents of \texttt{} \ \hline \end{tabular}\texttt{
} can be an absolute or symbolic address \texttt{#} denotes a denary number, e.g. \texttt{#123} \texttt{B} denotes a binary number, e.g. \texttt{B01001010} \texttt{&} denotes a hexadecimal number, e.g. \texttt{&4A}The ACC currently contains the following binary value.
\begin{tabular}{|c|c|c|c|c|c|c|c|} \hline 1 & 1 & 1 & 1 & 0 & 0 & 0 & 0 \ \hline \end{tabular}
Write the result after the instruction \texttt{OR B00001111} is run.
\framebox{$\square\,\square\,\square\,\square\,\square\,\square\,\square\,\square$}
The ACC currently contains the following binary value.
\begin{tabular}{|c|c|c|c|c|c|c|c|} \hline 0 & 0 & 0 & 1 & 1 & 1 & 0 & 1 \ \hline \end{tabular}
Write the result after the instruction \texttt{XOR #30} is run.
\framebox{$\square\,\square\,\square\,\square\,\square\,\square\,\square\,\square$}