1.1 Flashcards

1
Q

Explain what happens in the ‘fetch’ stage of the FDE cycle?

A
  • CU signals for address of an instruction in the PC is loaded into the MAR
  • The data in that memory address is fetched from memory and stored in the MDR
  • PC is incremented to point to the address of the next instruction
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2
Q

Explain what happens in the ‘decode’ stage of the FDE cycle?

A
  • Instruction is decoded by the control unit
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3
Q

Explain what happens in the ‘execute’ stage of the FDE cycle?

A
  • Fetching data from memory
  • Jumping to another instruction
  • Writing data back to RAM
  • Calculation is performed
  • Whole FDE process is repeated
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4
Q

What is clock speed?

A
  • The number of FDE cycles executed per second
  • Measured in GHz
  • Faster = more instructions can be executed
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5
Q

What is cache?

A
  • Small amount of very fast memory that temporarily stores recently used instructions
  • Level 1 is the fastest but it has the smallest capacity
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6
Q

What are cores?

A
  • A complete copy of CPU (processing unit)
  • More cores = more tasks can be executed at once (but requires communications and some softwares are not designed to make use of multicores therefore does not equal to double speed)
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7
Q

What are the factors affecting the speed of the CPU?

A
  • Clock speed
  • Number of cores
  • Cache size
  • RAM size
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8
Q

What is the control unit?

A
  • Decodes and executes instructions
  • Sends signals to control how data moves around the CPU
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9
Q

What is the arithmetic logic unit?

A
  • Performs mathematical calculations
  • Makes logical comparisons
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10
Q

What are registers?

A
  • Tiny and super fast memory holding a single instruction/address
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11
Q

What are the four registers?

A
  • Accumulator
  • Memory Address Register
  • Memory Data Register
  • Program Counter
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12
Q

What is the accumulator?

A
  • Holds results of calculations performed by the ALU
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13
Q

What is the memory address register?

A
  • Stores the address of current instruction/data to be fetched from or stored in memory
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14
Q

What is the memory data register?

A
  • Stores the data which has been fetched from or is to be written to memory
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15
Q

What is the program counter?

A
  • Stores address of next instructions to be run
  • Once instruction is fetched, value is incremented by one
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16
Q

What is an embedded system?

A
  • Has limited functions
  • Built into a larger machine
  • Cannot be modified once manufactured (read only)
  • Program controlling them is stored in ROM
17
Q

Give some examples of an embedded system

A
  • Washing machine
  • Smart watch
  • Air conditioning
  • Alarm clocks
18
Q

What are the benefits of embedded systems?

A
  • Highly efficient as firmware has very close control over the hardware
  • Easy to design because less components are required
  • Cheap to produce
  • Low in power consumption due to limited tasks to be executed
  • Compact in size
19
Q

State the purpose of the CPU

A
  • To process instructions requested by the user
  • To fetch, decode and execute them
20
Q

Explain what is meant by a computer system

A
  • An electronic device that takes input, processes data and delivers output
21
Q

What is the name of the computer architecture that is the basis of most digital computer systems?

A
  • Von Neumann architecture
22
Q

What is the FDE cycle?

A
  • Fetch decode execute
  • Complete process of retrieving an instruction, decoding it and carrying it out