computer systems Flashcards
(41 cards)
who is john von neumann
joun von neumann is a mathemation that described computer archetecture that is still revelant today , he described that there are four components to a computer. the CPU which processes the program, The memory which stores dara and programs, a bus connecting cpu and memort abd the input output devices
What is the CPU
the central processing unit carries out computations on data by following instructions resulting in an output it contains the control unit, the arithmatic logic unit ALU and registers
What is the ALU
the ALU is where arithmetic and logical processing takes place, The ALU receives instructions and data and operates on the data according to the instructions
what are registers
registers are temporary storage locations that CPU can access quickly, register is expensive meaning smaller capacity compared to other memories
What is the program counter
the program counter stores where the CPU is in the program sequence
what is the address registers
address registers store memory addresses . A memory address is a value that indicates a specific location in memory
explain memory
Modern computers can store programs internallly in memory as well as inout and output data (RAM)
what is RAM
random access memory is a temporary memory.. it holds the data and instructions of the program that is being excuted by the CPU and is volatile
what is ROM
read only memory typical use for ROM is the computers BIOS basic input output systems. this is a small amount of ROM that is. used to store the computers startup routines. the BIOS preform necessary check then give control to the operation system
are RAM and ROM primary or secondary
primary
what is the fetch-execute cycle
As the CPU processes instructions. It runs through this cycle over and over again. The CPU fetches next instruction from memory. Instruction is found at a memory address and is stored in binary code. CPU decode the binary code revealing instruction, which is executed
what is the clock
The clock ensures operations of the CPU and other components are timed accuratelly and ensures all the step by step instructions are perfectly sychronised
what is the bus
The bus connects the CPU and memory
input and output devices
all part other than CPU, memory and bus are consided I/O devices
give examples of I/O devices
secondary storage, USB devices, keyboard or printers, screens output, touchscreens input
what is secondary storage
secondary storage is non volatile primary storage is smaller and more expensic=ve than secondary
what are magnetic hard drives
magnetic hard drives consist of a platter rotating at a high speed and a head moves across platter reading information
what are solid state drives
they are faster and more durable with no moving parts SSDs are based on flash memory but are more expensive
what is the motherboard
The mother board is a circuit board that devices mount on(when you plug a usb device into a computer you are physically connecting to the motherboard) - (includes CPU, main memory, hard drives and other I/O devices)
Binary code
computers use binary code to represent all information - binary stands for two. on signal present and off no signal in many devices the signal are high and low signals above certain voltage is high and below that volt is low
what is an analog device
eg black and white tv use a huge range of values, these can get confused making noise
what is electric current
is th eflow of electrons in one place
what is voltage
an electron experiences a force when a difference in charge exiss between its location and another locatation, this difference is called voltage
what is resistance
resistance is a measure of how much a material resists or obstructs the flow of electic current
