Advantages And Disadvantages Of Parallel Computing

AN ABSTRACT ON MESOCHRONOUS PIPELINING

PARALLEL COMPUTING is a form of computation in which many calculations are carried out simultaneously, operating on the principle that large problems can often be divided into smaller ones, which are then solved at the same time. There are many alternatives to achieve parallel computing, namely

1. Parallel processing: In computers, parallel processing is the processing of program instructions by dividing them among multiple processors with the objective of running a program in less time. In the earliest computers, only one program ran at a time. With single-CPU, single-core computers, it is possible to perform parallel processing by connecting the computers in a network. However, this type of parallel

Multitasking programming -In computing, multitasking is a concept of performing multiple tasks (also known as processes) over a certain period of time by executing them concurrently. The processes are executed depending on the time slice given by the vendor. As a result, a computer executes segments of multiple tasks in an interleaved manner, while the tasks share common processing resources such as central processing units (CPUs) and main memory. Multitasking does not necessarily mean that multiple tasks are executing at exactly the same time. In other words, multitasking does not imply parallel execution, but it does mean that more than one task can be part-way through execution at the same time, and that more than one task is advancing over a given period of time

3. Pipelines- In computing, a pipeline is a set of data processing elements connected in series, where the output of one element is the input of the next one. The elements of a pipeline are often executed in parallel or in time-sliced fashion; in that case, some amount of buffer storage is often inserted between elements. Pipelining is an implementation technique where multiple instructions are overlapped in execution. The computer pipeline is divided in stages. Each stage completes a part of an instruction in

Fetching the instruction: The next instruction is fetched from the memory address that is currently stored in the program counter (PC), and stored in the instruction register (IR).. At the end of the fetch operation, the PC points to the next instruction that will be read at the next cycle.

2. Decode the instruction: During this cycle the encoded instruction present in the IR is interpreted by the decoder. The control unit of the CPU passes the decoded information as a sequence of control signals to the relevant function units of the CPU

3. Execute the instruction: The CPU performs the actions required by the instruction such as reading values from registers, passing them to the ALU to perform mathematical or logic functions on them, and writing the result back to a register. If the ALU is involved, it sends a condition signal back to the CU. The result generated by the operation is stored in the main memory, or sent to an output device. Based on the condition of any feedback from the ALU, Program Counter may be updated to a different address from which the next instruction will be