The Brain
Outline the architecture of the central processing unit (CPU).
The CPU consists of the Arithmetic Logic Unit (ALU), the Control Unit (CU), and various registers.
The ALU handles calculations, the CU manages the flow of data, and registers provide high-speed internal storage for immediate operations.
Distinguish between RAM and ROM.
RAM is volatile and used for running programs/data; ROM is non-volatile and used for permanent instructions like the BIOS.
List the four stages of the machine instruction cycle.
Fetch, Decode, Execute, and Store.
Define the three basic logic gates used in DP Computer Science.
AND, OR, and NOT.
Define the "Operating System" (OS).
Software that manages computer hardware/software resources and provides common services for computer programs.
What are the specific functions of the ALU and the Control Unit?
The ALU performs all arithmetic (+, -) and logical (AND, OR) operations; the CU decodes instructions and controls the fetch-execute cycle.
Explain the use of cache memory.
It is high-speed memory between the CPU and RAM that stores frequently used data to speed up processing.
What happens during the "Decode" stage of the cycle?
The Control Unit (CU) interprets the instruction held in the Instruction Register to determine what action is required.
Construct a truth table for an "XOR" gate.
Output is 1 only if inputs are different (0,1 or 1,0); otherwise, it is 0.
Identify two resources the OS must manage.
Memory, Peripherals, Processor time, or Storage.
Identify the two registers students are required to include in a block diagram of the CPU.
The Memory Address Register (MAR) and the Memory Data Register (MDR).
The MAR holds the address of the data to be fetched, while the MDR holds the actual data being transferred to or from memory.
Define the term "Primary Memory."
Memory that is directly accessible by the CPU, primarily consisting of RAM and ROM.
Where does the CPU "Store" the result after the "Execute" phase?
Results are stored back in the registers or primary memory (RAM).
What is the output of a NAND gate if both inputs are 1?
0 (False)
NAND is the inverse of AND; since AND(1,1) is 1, NAND(1,1) is 0.
What is the purpose of "Virtual Memory" in an OS?
To allow the execution of processes that are larger than the available physical RAM by using secondary storage.
Explain the relationship between the MAR and the MDR during a "fetch" operation.
The CU places the address in the MAR; the data at that address is then copied from RAM into the MDR.
Explain the need for persistent storage (Secondary Memory).
To store data and programs permanently when the power is turned off (non-volatile storage).
How does the "Fetch" stage utilize the Data Bus?
The Data Bus carries the actual instruction/data from RAM to the CPU's MDR.
Describe the purpose of a truth table in circuit design.
To show all possible input combinations and their resulting outputs for a logic circuit.
List two common software applications.
Word processors, Spreadsheets, DBMS, Web browsers, Email clients, or CAD.
Describe the primary role of the Control Unit (CU) in the machine instruction cycle.
It coordinates the movement of data by providing timing and control signals to other components.
Why is cache memory considered a trade-off in computer design?
It is significantly faster than RAM but much more expensive and has a smaller capacity.
Explain how the program counter (PC) facilitates the cycle.
It holds the memory address of the next instruction to be fetched, incrementing after each fetch.
Identify the gate that produces a 1 output only if all inputs are 0.
A NOR gate.
Outline the function of the "Kernel" in an OS.
The core part of the OS that manages system resources and the communication between hardware and software.