1. Different computing devices in Arnold’s home use different processor architectures. One processor architecture is the Harvard architecture.
a) Describe the Harvard architecture
[2]
Login to save your answers
📋 Mark Scheme (a):
1 mark per bullet up to a maximum of 2 marks, e.g:
• Uses separate memory blocks for instructions and
data
• Has separate buses (data and address) for data and
instructions
• Has fixed memory sizes for data and Instructions
• Instruction memory may be ROM
/ 2
b) Arnold has a smart washing machine. Explain why the Harvard architecture is suitable for a device like this.
[2]
Login to save your answers
📋 Mark Scheme (b):
1 mark per bullet up to a maximum of 2 marks, e.g:
• Fixed instruction size
• No need for memory to be shared between data and
instructions
• Removes need for secondary storage
• Instructions would never be changed
/ 2
2. A charity uses a desktop computer to record financial donations that it receives. The computer
contains a single core, 2.4GHz processor with 2MB cache.
(i) Describe what is meant by the term ‘Von Neumann architecture’.
a) The processor uses the Von Neumann architecture.
[2]
Login to save your answers
📋 Mark Scheme (a):
Both data and instructions share the same memory
Instructions and Data stored in same format
A single set of buses / same bus for instructions &
data (to connect CPU to Memory and I/O)
Has a (single) control unit
Has an ALU.
Has ways to input and output.
Has access to storage,
Works sequentially through instructions // follows
Fetch-execute cycle
(Special) registers within CPU
Based on stored program concept
/ 2
b) Give one way that the Harvard architecture differs from the Von Neumann architecture.
[1]
Login to save your answers
📋 Mark Scheme (b):
Separate memory for data and instructions / Multiple
memory units
Different (sets of) buses one for instructions & one
for data/ instructions and data can be accessed
concurrently.
/ 1
3. The charity is concerned that the performance of the computer is not sufficient and wishes to
replace the processor.
Give two features of a replacement processor that would increase the typical performance of
the computer.
[2]
Login to save your answers
📋 Mark Scheme:
Higher/faster clock speed
More cores//dual/quad/etc core
More cache memory.
/ 2
4. A program is run on a processor that allows pipelining.
Define the the term 'pipelining'
[3]
Login to save your answers
📋 Mark Scheme:
One instruction can be fetched while another is
being decoded…
…and another is executed
The output of one process/instruction is the input of
the next.
Concurrent processing of multiple instructions //
completing multiple FDE cycles at once
/ 3
5. A processor contains registers including the accumulator and the program counter. The contents of these registers are modified during the Fetch-Decode-Execute cycle.
a) Describe how the accumulator is used during the Fetch-Decode-Execute cycle.
[2]
Login to save your answers
📋 Mark Scheme (a):
Holds all input/output
Holds results of calculations (from the ALU)
Checked for conditional branching (e.g. BRZ)
Stores data which has come from the MDR/RAM
/ 2
b) Describe how the program counter is used during the Fetch-Decode-Execute cycle.
[2]
Login to save your answers
📋 Mark Scheme (b):
Holds the address/location of the next instruction (to
be executed/fetched)
Contents copied to the MAR at start of FDE
Incremented (by one) on every cycle
Can be changed by branch/jump instructions
/ 2
c) State the name of three other registers that are used during the Fetch-Decode-Execute cycle.
[3]
Login to save your answers
📋 Mark Scheme (c):
Memory Address Register // MAR
Memory Data Register // MDR
Current Instruction Register // CIR
Index Register // IR