1.1 Sytems Architecture Flashcards
What is a general purpose computer ?
a computer that is designed to be able to carry out many different tasks.
What is an application ?
A software program that allows a user to perform a specific task.
What is hardware ?
the physical components of the computer
What is software ?
the programs that run on a computer
What is the purpose of the CPU ?
- process data and instructions
- control the rest of the computer system
What is the first step of the fetch - decode- execute cycle ?
memory address held in the PC is copied into the MAR.
What is the second step of the fetch - decode- execute cycle ?
address in the PC is then incremented
by one.
What is the third step of the fetch - decode- execute cycle ?
processor sends a signal along the address bus to the memory address held in the MAR.
What is the fourth step of the fetch - decode- execute cycle ?
instruction/data held in that memory address is sent along the data bus to the MDR.
What is the fifth step of the fetch - decode- execute cycle ?
The instruction/data held in the MDR is copied into the CIR.
What is the sixth step of the fetch - decode- execute cycle ?
The instruction/data held in the CIR is decoded and then executed.
Results of processing are stored in the ACC.
What is the seventh step of the fetch - decode- execute cycle ?
The cycle returns to step one
What are the six main components of the CPU ?
control unit (CU)
arithmetic logic unit (ALU)
registers
cache
buses
clock
What is the Control Unit ?
The component of the CPU that manages instructions.
What is the ALU ?
performs arithmetic and logic calculations.
What is a register ?
high speed memory that stores data to be processed.
What is a bus ?
A channel of communication used to transport data and instructions in the CPU
What is a clock ?
sends out regular pulse to synchronise the computer’s hardware components.
What are the three main functions of the Control Unit ?
- fetch ,decode, execute instructions
- issues control signals that control hardware
- moves data around the system
What are the two main functions of the ALU ?
- performs arithmetic and logical operations
- gateway between primary memory and secondary storage
What is the purpose of the cache ?
used to temporarily hold data and instructions that the processor is likely to reuse
What are the two types of cache ?
L1, L2
What are the properties of L1 cache ?
- extremely fast transfer rates
- very small in size.
What does L1 cache hold ?
most frequently used instructions and data.
What are the properties of L2 cache ?
- Bigger in capacity than L1
- Slower in speed
What does L2 cache hold ?
data and instructions that are needed less frequently.
What is Von Neumann architecture ?
A stored program concept
What are the key elements of Von Neumann architecture ?
- D and I stored in binary digits
- D and I stored in primary memory
- Instructions are fetched serially
- the processor decodes and executes an instruction, before cycling around
-The cycle runs till there is no more variables
What is the purpose of the MAR ?
- holds the address of the current instruction that is to be fetched from memory
- or the address in memory to which data is to be transferred
What is the purpose of the MDR ?
- holds the contents found at the address held in the MAR
- or data which is to be transferred to primary memory
What is the purpose of the CIR ?
holds the instruction that is currently being decoded and executed
What is the purpose of the ACC (Accumulator)?
holds the data being processed and the results of processing
What is clock speed ?
The frequency of the pulses
What are the three factors that affect CPU performance ?
- clock speed
- cache size
- number of cores
How is clock speed measured ?
Hertz - Hz
What are the effects of overclocking ?
long term damage to the CPU as it is working harder and producing more heat.
What is the Program Counter ?
holds the memory address of the next instruction to be fetched from primary memory
What is an embedded system ?
A special purpose computer built into another device.
What are the advantages of embedded systems over general purpose computers ?
- limited functions = cheaper to design +build
- Require less power
- Don’t need much processing power
Do embedded systems require frequent updates ?
YES
