3.7.1 Internal hardware components of a computer - 3.7.2 The stored program concept Flashcards
definition of the internal components of a computer system
The internal components of a computer system consists of the internal hardware required to process and store data, and communicate with external devices such as printers, peripherals and display screens
examples of the main internal components
processor
main memory
I/O controllers
system buses
what is the role of the processor
the processor executes program instructions
it fetches decodes and executes data fetched from main memory
the instructions are written in machine code that the processor instruction set can understand
what is the main memory
memory that is directly accessed by the processor
each location of the MM has a physical address in which binary sequences are stored
made of the RAM which the processor accesses to fetch decode execute
and the ROM, which stores a limited number of read only instructions that are needed to run the computer
what are buses
buses are a connection of parallel wires used to connect the processor to I/O controllers and to memory to exchange data
they also connect the components of the processor to each other
data bus
data bus transfer data between the cpu and memory It is bi-directional from the cpu and the I/O controller of memory devices (it can transfer data to and from)
it is one way for I/O controller of input output devices
the importance of the size of data bus
the size of the data bus is measured as its width
e.g. if its width is 8 parallel wires it can transfer 256 bits of data in one pulse of the clock
this can affect the overall speed and performance of the computer
adress bus
specifies physical addresses of memory so that the data bus can access it forit to be either read from or written to
used by the processor to access any data item or memory location from any device or the memory
it is unidirectional (only access by processor and only access I/o controller or memory)
control bus
coordinates and synchronises the flow of data and operations in a computer system
it controls access to address buses and data as these are being shared between several components
it can send communication requests between two unit
it can grant communication requests
synchronise communication between components using clock pulses
specify the type of data being sent(data value, instructions or addresses)
examples of control signals
memory read
memory write
bus request/grant/busy
interrupt signals
clock signals
what are I/O controllers
circuitry that is needed to connect input out put devices to the processor.
They control data flow between the processor and I/O devices
they convert signals into a form that can be understood by the processor
what’s the advantage of I/O controllers
there are many different types of devices and processors, so I/O controllers are useful in allowing new devices to connect without having to redesign the processor
they can buffer data between the processor and device as the I/O device will work much slower than the processor
what is the stored program concept
the idea that instructions(programs) as well as data can both be stored in electrical memory and executed serially.
this was a step up from before as machines had to be reprogrammed each time a new program was to be decoded and the previous program was lost.
machines can now do amultitude of tasks without having to be manually reprogrammed
what is a computer architecture
Computer architecture refers to the structure and organisation of a computer system. It specifies the components that make up a computer system and describes how these are interconnected, how they interact with each other, and how they are managed.
what is the von Neumann architecture
A computer architecture where the instructions and data are stored in a single memory location. They share data and address buses as a resultw
