2.3 architecture Flashcards
what is a processor?
-CPU interprets and carries out basic instructions to process the computers data and exchanges this data with other components + peripherals
Control unit
manages the order instructions are executed, manages fetch/execute cycle, controls input and output of data + implements loops and jumps.
ALU
- digital circuit which carries out mathematical and logical operations on data associated with instructions being executed. - loads data from input registers, receives instructions from the CU on what operation to perform and stores result in an output register.
Clock
-pulses are provided by an internal clock which helps to synchronise all internal processes/ components by generating pulses at a constant rate.
=Determines how many computer instructions are carried out each second
main memory
-RAM and internal memory
-immediate access memory
-Volatile
-stores a portion of the OS, application software currently running + other data items the processing unit needs when carrying out operations
ROM
contents are permanent and written onto ROM when it’s first made and cannot be altered.
non-volatile
stores programs such as basic instructions needed to start a computer and launch the OS
Cache
stores copies of contents of most frequently accessed memory locations (e.g data, applications programs data files etc)
CPU first searches cache before searching main memory
Can be accessed much faster than RAM
data bus
allows for the transfer of data between one component and another
if an item of data is to be stored in memory, the data item will travel to memory location via data bus
control bus
carries commands from the CPU to other devices in relation to the instructions being executed at a particular time.
if an item of data is to be stored in memory the control bud will carry the write command to the memory location
address bus
used to identify a physician location in memory to be identified
stores location in memory to be accessed for reading/writing data
I/O controllers
series of microchips which help in the communication of data between CPU and motherboard
main purpose is to help in the interaction of peripheral devices with the control units. I/O devices cannot be connected directly to the processor so they need a specific I/O controller.
Program Counter
stores the address of the next program instruction to be executed
MAR
stores the address of the memory location to be accessed for a instruction/ read or write
MDR
stores data that has just been fetched from memory or data waiting to be stored/written to a location in memory
CIR
stores the instruction currently being executed by the processor
