1.1 Flashcards
(40 cards)
What is the brain of the computer
CPU
Types of output a computer can produce
Visual, Sound, Vibrational
Describe the control unit and its function
Co-ordinates all activities of CPU
Directs flow of information between CPU and other devices
Accepts next instruction, decodes it and handles its execution
Sends memory read-write signals on the control bus
Co-ordinates and communicates with all components in the CPU
Describe the program counter and its function
Holds address of next instruction to be executed
Either, next instruction to be executed in a sequence
Or address jumped to from jump or branch command
Describe the Memory Address register and its function
Holds the addresses of memory locations for data and instructions for which the contents are to be fetched or to which data is to be written
Sends these addresses down to memory down the address bus
Describe the Memory Data register and its function
Temporarily store data which is read from or written to memory
Sometimes known as memory buffer register
All data uses MDR and data bus
Describe the Current Instruction register and its function
Holds the current instruction being executed
Contents of MDR copied here if instruction
Contains the opcode and operand
Describe the Arithmetic Logic Unit and its function
Performs arithmetic and logical operations on data
ADD MULTIPLY
SUBTRACT DIVIDE
Bitwise operation shifts left and right
Results held in ACC
Describe the accumulator and its function
General purpose register
Stores temporary data while instructions are being carried out
Results of ALU carried out are stored here
Describe the address bus
Carries memory addresses that identify where the data is being read from or written to
Uni-directional
Describe the data bus
Carries the binary 1s and 0s that make up the actual information transferred around the computer
Bi-directional
Describe the control bus
Carries the command and control signals to and from every component of the CPU
Bi-directional
What is a computer
An electronic device that takes an input as data processes and produces an output
What is a program
A set of instructions
Describe the F-D-E cycle
The program counter is checked
The address stored is copied to the MAR
The address is sent along the address bus to main memory
The CU sends a read signal along the control bus to main memory
Contents stored in main memory are sent along the data bus to the MDR
Instructions are copied into the CIR
Program counter is incremented by 1
The instruction held in the CIR is decoded by the decode unit
Load address in accumulator (for load)
Execution (based on load)
Address sent to MAR
Address sent down address bus to main memory
Control unit sends a read signal along the control bus to main memory
Contents are sent along the data bus to the MDR
Contents of MDR are copied to ACC
What is the Opcode
What is done in the F-D-E cycle
What is the Operand
What the opcode is done to
What is program branching
Where different lines of code are executed depending on if certain conditions are met
What is clock speed and its measurement
hertz, number of clock cycles (FDE cycles per second)
What are the 3 factors affecting CPU performance
Cache size, clock speed, number of cores
What is cache
Temporary storage of data to be read from and written to
Located on or near CPU
Very fast to access
What is a core
A complete copy of a CPU
Increase clock size increase performance
Clock cycle = no of FDE cycles per second
More FDE cycles done equals more instructions executed increasing performance
Increase cache size increase performance
More frequently used instructions can be stored in the fast to access cache
increasing performance
