Topic 4 Computers Flashcards
List a range of input devices
Mouse
Keyboard
Microphone
Camera
List a range of output devices
Monitor
Printer
Speakers
Vibration pack
Describe the relationships in the Input, Process, Output model.
All output is the result of inputs which have been processed,
ie. Input -> Process -> Output
Name all of the components of the CPU (Central Processing Unit)
Control Unit Decoder Clock Arithmetic Logic Unit Cache Buses Registers
If a CPU has a clock speed of 3GHz, what does this actually mean?
It can carry out 3 billion processing cycles per second.
What significant factors affect the performance of a CPU?
Clock speed Cache Size Number of cores Size and type of RAM Hard drive speed
Describe Von Neumann architecture.
Programs and data stored in the same memory (RAM). Components are:
- CPU
- Program Counter
- Memory
- Input / Output
Describe the role of the control unit in a CPU.
- Coordinates the actions of the computer.
- Sends control signals to other parts of the CPU.
- Contains the decoder which works out what the instructions mean
Describe the role of the arithmetic logic unit (ALU) in a CPU.
- Performs arithmetic and logical operations
- Addition, subtraction,multiplication, division
- Comparisons between two different numbers (eg , <= etc)
Name the four registers used in the Fetch-Decode-Execute cycle
- Program Counter (PC)
- Memory Data Register (MDR)
- Memory Address Register (MAR)
- Accumulator
State what is performed at each stage of the Fetch-Decode-Execute cycle.
Fetch: The next instruction to be executed is transferred from RAM into the CPU.
Decode: The control unit (decoder) interprets the instruction.
Execute: The control unit carries out the instruction. If calculations are needed, these are performed by the ALU.
Describe RAM
RAM - Random Access Memory
- Stores data and instructions while a program is running. -Main memory of the computer.
- Volatile - data is lost if power turned off
Describe ROM
ROM - Read Only Memory
- Stores instructions to initialise hardware and load operating system
- Data can only be read from ROM, not written to it
- Non-volatile, data retained when power is off
Describe cache memory
- Very fast memory
- Stores recently or frequently used instructions to speed up processing
- Instructions don’t have to be fetched from RAM as often
- Too expensive to use as RAM
Name the three main types of secondary storage device
- Magnetic discs
- Optical discs
- Solid-state (flash memory)
