3. Hardware Flashcards
(54 cards)
What are embedded systems?
- A small computer that forms part of a larger system, device or machine
- They tend to have one or limited number of task that can be performed
What is the Von Neumann architecture?
it’s where both the data and the software that are currently being used are stored in
computer memory (RAM).
What is the purpose of a CPU?
- To proccess Data
- Where all sorting, searching, calculating and decision making takes place
How does the CPU relate to the fetch decode execute cycle?
The CPU:
- Fetches instructions from the memory (RAM)
- It Decodes those instructions
- It then Executes (carries out) the instructions
What are the main components of the CPU?
- Control Unit (CU)
- Arithmetic Logic Unit (ALU)
- Registers
- The CPU also contains data buses
What does the Control Unit (CU) do?
- controls the way data moves around the CPU
- controls/monitors the flow of data between the CPU and other hardware components
- executes the instructions provided by the program
What does the Arithmetic Logic Unit (ALU) do?
- performs standard arithmetic operations such as addition, subtraction etc
- deals with logic and comparisons such as “is this value greater than that value?:
What do the Registers do?
Its a type of temporary memory located inside the CPU. Registers are super fast and are used instead of RAM.
What do Buses do?
Their role is to carry data around the system.
What is the Address Bus?
Carries the addresses of data (but not the data) between the processor and memory
What is a Data Bus?
Carries data between the processor, the memory unit and the input/output devices
What is a Control Bus?
Carries control signals/commands from the CPU (and status signals from other devices). Therefore coordinating all the activites within the computer.
What is a program counter (PC) ?
- Hold value of address of next intruction to run
What is Memory Address Register (MAR)?
- Holds location in memory (address) of next piece of data or program to be fetched
What is Memory Data Register (MDR)?
- When the program instruction is fetched from memory, it is temporarily held in this register
What is Current Data Register (CDR)?
- holds the current instruction to be executed, having been fetched from memory.
What is the full steps of the Fetch, Decode, Execute Cycle?
- PC had address of next Instruction
- PC copied to MAR
- Lookup MAR and get contents and copy into MDR
- Copy MDR into CIR
- PC incremented by 1
- Instruction decoded and executed
- Repeat.
What is Clock Speed?
The Clock is a vibrating crystal inside the CPU. The faster it vibrates that faster
instructions are processed.
What is Hertz?
number of cycles/operations per second
What are Cores?
A processor has a “core” in which instructions are executed. There
can be multiple cores: Dual Core, Quad Core.
Each core executes instructions independently.
What is Multitasking?
working on different tasks at the same time
What is Parralel Processing?
all cores work together on the same task.
What is Cache?
Very fast, and usually a very small amount of memory on the processor chip.
- As programs are executing – the Cache holds commonly used instructions
What affects the performance of a Computer?
ClockSpeed, Cores and Cache Size