computer system internal components - the processor - main memory - i / o controllers - buses...
TRANSCRIPT
Computer System Internal components
- The processor- Main memory- I / O controllers- Buses
External components (peripherals). These include:
- keyboard- mouse- printer - disk drives
Three Box Model (von Neumann architecture)
Processor and MemoryProcessor executes programs and supervises
functioning of the rest of the systemUse Google to find out what Moore’s law is and
put into your notesMemory – use e.g. in Google : define RAM to
find out what it isRAMROMEEPROM
BusesBus: A set of parallel wires
connecting 2 or more components of the computer
System BusesADDRESS BUS – carries address from CPU to
memory
DATA BUS – carries data to CPU from memory
CONTROL BUS – for control signals
These connect the processor, memory and I/O controllers.
Control BusSignals travel in both directionsOnly 1 component can use a bus at a time so
the Control bus transmits command, timing and status information
between componentsto prevent conflict.
Data BusSignals travel in both directions
Typically consists of 6, 16, 32 or 64 separate lines for moving data and instructions between components
The width of the data bus is helps determine overall system performance
Address BusAddresses travel one-way – to memory or to
an I/O controller
The width determines the maximum possible memory capacity of the system
1 line allows 21 maximum addressable cells8 lines allows 28 maximum addressable cells - 256
20 lines allows 220 maximum addressable cells – 1048576
Central Processing Unit
Processor
Main Memoryor
Immediate Access Store
KeyboardInput
Controller
(Disk) I/O Controller
VDU Output Controller
Visual Display Unit
Secondary Store orBacking Store
(e.g. Magnetic Disk)
Keyboard
Control Bus
Data Bus
Address Bus
Components of a simple computer system
Long term storage of programs & data
I/O ControllersThe processor controls and communicates with
a peripheral device through an I/O controller.
Some controllers operate both input & output of bits eg.
Floppy disk controller
Some controllers operate in one direction only eg.
VDU controller - output Keyboard input controller - input
I/O ControllersThe controller is an electronic circuit board
consisting of 3 partsAn interface to connect to the system or I/O
busA set of registersAn interface to connect to the device’s cable