There are four ways a computer system communicate with I/O devices. Direct control Programmed I/O Interrupt driven I/O Direct memory access Direct control : Old and obsolete technique. CPU interact directly with I/O devices with the help of dedicated program. Processing is extremely slow. Programmed I/O : CPU and I/O devices communicates through ‘Device Status
Principle of ‘locality of reference‘ : This principle suggests that at any given time, the CPU will be accessing memory in a localized region of memory. When the instruction is found in the cache, the transaction is called a hit else a miss. When cache memory sits along side the main memory then the architecture
A CPU executes an instruction store in the main memory of the computer. An instruction usually consists of two parts: Op-code (Operation to be performed) and operands (on which operation to be performed ( can be address or data itself)). CPU clock controls the timing of each operation. The length of time taken to go
A bus is a group of current-conducting wires over which data is transferred from one device to another. Their types are : Data bus : Transfers data Size is generally proportionate to CPU power. e.g. 64 bit CPU will have 64 bit wide bus. Generally bidirectional. Address bus : Carries the address of the device.
The main components of the CPU are– control unit (CU), arithmetic nd logical unit (ALU) and a set of registers. Control Unit : Responsible for controlling the movement of data and instructions in and out of the memory and the CPU. Decodes the fetched instruction and initiates the desired operation to be performed by the
A modern computer have four main components : Memory : Primary( is a semiconductor memory, volatile e.g. RAM) and Secondary (non-volatile auxiliary memory e.g. Hard-disk) memories. Input unit : e.g. Keyboard, mouse. Central Processing Unit (CPU). Output Unit. e.g. Monitor, Printer.
A computer is a digital machine that generates, processes, stores and transmits information. The essential design of a computer is bases on Von Neumann architecture consisting of two components – a processor and a tore connected through a communication channel. The program instructions and associated data are loaded into the store. Therefore, such a machine