Fundamentals of Computer Organisation and Architecture | AQA A-Level Computer Science (7517)

Fundamentals of Computer Organisation and Architecture

133 questions
11 subtopics
Paper 2: the written exam
Paper 2

The stored program concept, the processor and its registers, the Fetch-Execute cycle, instruction sets and addressing modes, interrupts, performance factors, and input, output and storage devices.

Examined on Paper 2.

Sample questions from Fundamentals of Computer Organisation and Architecture

Answer each one closed book first, then open the answer.

Internal components, buses and von Neumann and Harvard architectures

Name the basic internal components of a computer system.

Show the answer
The processor, main memory, the address bus, the data bus, the control bus, and the input/output controllers that connect peripherals to the system. All of these are mounted on or attached to the motherboard, and the buses are the wires that carry signals between the rest.
The Stored Program Concept and the Processor

Name the major components of a processor.

Show the answer
The arithmetic logic unit, the control unit, the clock, a set of general-purpose registers, and the dedicated registers: the program counter, the current instruction register, the memory address register, the memory buffer register and the status register. The buses inside the processor connect them.
The Fetch-Execute cycle

Name the three stages of the Fetch-Execute cycle and say in one line what each does.

Show the answer
Fetch: the next instruction is copied from main memory into the processor. Decode: the control unit works out from the opcode what operation is required and in which addressing mode. Execute: the operation is carried out. The cycle then repeats, continuously, for as long as the processor is running.
The processor instruction set

What are the two parts of a machine code instruction?

Show the answer
The opcode and one or more operands. The opcode says which operation is to be carried out. The operand supplies what it is to be carried out on, and may be a value, a memory address or a register.
Addressing modes

Which two addressing modes are used here, and what does an addressing mode mean?

Show the answer
Immediate addressing and direct addressing. An addressing mode is the rule for how the operand of an instruction is to be interpreted, that is, how the processor works out from the operand bits where the actual datum it must use is to be found.
Machine-Code Operations

Which basic machine-code operations make up the instruction set used at this level?

Show the answer
Load, add, subtract, store, branching both conditional and unconditional, compare, the logical bitwise operators AND, OR, NOT and XOR, logical shift right, logical shift left, and halt.
Factors affecting processor performance

Name the six factors affecting processor performance.

Show the answer
The number of cores, the amount of cache memory, the clock speed, the word length, the width of the address bus and the width of the data bus.
Input and output devices

What does RFID stand for, and what are the two parts of an RFID system?

Show the answer
Radio Frequency Identification. The two parts are the tag, a tiny microchip holding an identifying number and any other stored data, attached to an antenna and often embedded in a label, card or capsule; and the reader or interrogator, which has its own antenna and transmits and receives the radio signals.

The 11 subtopics

One subtopic is one session. Work down the list.

Subtopic	What it covers	Questions
Internal components, buses and von Neumann and Harvard architectures	Recall questions on the processor, main memory and I/O controllers, the address, data and control buses, addressable memory, and the von Neumann and Harvard architectures and the von Neumann bottleneck.	17
The Stored Program Concept and the Processor	Recall questions on what makes a machine a stored-program computer, why the idea mattered, and the components of the processor.	18
The Fetch-Execute cycle	Recall questions on the fetch, decode and execute stages, the register used at each step, register transfer notation, and what changes when a branch is taken.	14
The processor instruction set	Recall questions on opcode and operand, why an instruction set is processor specific, and decoding a given byte into its operation and its operand.	10
Addressing modes	Recall questions on immediate against direct addressing, what ADD 20 does under each, their relative speed and flexibility, and why a loop counter needs direct addressing.	8
Machine-Code Operations	Recall questions on the instruction set at this level and on the load, store, add and subtract instructions.	12
Shifts, Halting and Assembly Language Programs	Recall questions on logical shifts left and right and their arithmetic effect, the halt instruction, hand-tracing assembly language programs with loops and branches, and why labels are used.	9
Interrupts	Recall questions on what generates an interrupt, the service routine, the effect on the Fetch-Execute cycle, and why the volatile environment is saved on a stack.	10
Factors affecting processor performance	Recall questions on cores, cache, clock speed, word length and bus widths, and on why each of them stops delivering gains at some point.	9
Input and output devices	Recall questions on barcode readers, digital cameras, laser printers and RFID, how each works, and the situations each is and is not suited to.	11
Secondary storage devices	Recall questions on hard disks, optical disks and solid-state drives, how each stores data, what makes up access time, and which suits a given job.	15

Fundamentals of Computer Organisation and Architecture is 133 of the 1,516 questions in the guide.Get the guide, £9

How the guide is worked

Answering a question from memory stores it far better than reading the answer again. The guide runs that as a fixed procedure on one subtopic at a time, about twenty minutes a session.

Step 1 · Closed book
Cover the answers. Work through one subtopic and write down what you can. Leave blanks where you have nothing.
Step 2 · Open book
Go back to the top. Read each printed answer and write it out in full, including the ones you had right.
Step 3 · Closed book again
Same questions, same order, from memory. The gap between pass one and pass three is the session result.

Read the full method, the return schedule and the research behind it.