SLR1.1 Flashcards
what is a computer
an electronic device that takes an input, processes data and delivers output.
e.g.
input=2
process=x4
output=8
how does a computer process data
computers follow a set of instructions called a computer program
what does the memory of a computer do
stores the program
what CPU stand for
central processing unit
purpose of the CPU
fetches instructions
decodes instructions
executes instructions
how computer carries out its functions
the fetch-execute cycle
what does the CPU consist of
it consists of the ALU, CU, cache and registers
ALU
arithmetic logic unit
performs calculations and logical desicions
CU
control unit
sends electrical signals to control how data moves around the CPU
decodes instructions
cache
temporary storage of data and instructions being read and written from
provides fast access to frequently used instructions and data without having to go to the main memory
faster processing
what are registers
A component for holding short term memory, used to store addresses or data currently being worked on
Von Neumann architechture
consists of a CU, ALU, RAM and inputs and outputs
what was the von Neumann architecture based on
the stored program concept
where are instructions and program data stored
in the same memory in binary form
what is a stored program computer
a computer that has changeable programs
what registers does the von Neumann architecture contain
PC - which holds the address of the next instruction in memory
MAR (memory address register) - holds the address of where data needs to be fetched and stored
MDR (memory data register) - which holds fetched from, or to be written to memory
Accumulator - holds the results of calculations
embedded system
a computer system with a dedicated function within a larger mechanism
examples of embedded systems
toasters, cars and defibrillators
properties of an embedded system
lower power consumption
small size
low cost per unit
clock speed
the number of instruction cycles per second
measured in hertz
core
a copy of a CPU
quad core
has 4 seperate cores
resolution
number of pixels used in a given area. It therefore
describes the detail of an image, with high resolution images being highly detailed
factors that affect the speed of the CPU
cache size
clock speed
number of cores
ram
what happens during the fetch execute cycle
Instruction is fetched from memory
Instruction is decoded to figure out what the CPU needs to do
Instruction is brought to the MDR to be executed
The cycle repeats
