Parallel Processing and Data Transfer Modes in a Computer System

Parallel Processing and Data Transfer Modes

• A parallel processing system offers concurrent data processing to lengthen the execution time rather than processing each instruction one after the other.
• In this case, the system should be able to execute two or more instructions simultaneously and may have two or more ALUs. The goal of parallel processing is to boost throughput and accelerate computer processing speed.

NOTE: The quantity of instructions that can be carried out in a certain amount of time is called throughput.

• Different levels of complexity can be used to view parallel processing. The kind of registers that are used at the lowest level allows us to differentiate between serial and parallel operations. When dealing with more complex tasks, parallel processing can be accomplished by utilizing several functional units that carry out numerous tasks concurrently.

Parallel Processing and Data Transfer Modes in a Computer System

Computer System Data Transfer Modes

• A computer can be classified into four main groups based on the data transfer mode it uses:

1. SISD
2. SIMD
3. MISD
4. MIMD

SISD (Single Instruction Stream, Single Data Stream)

• It depicts how a single computer with a control unit, processor unit, and memory unit is organized. Instructions are carried out in order. 
• Multiple functional units or pipelining can be used to accomplish it.

SIMD (Single Instruction Stream, Multiple Data Stream)

• It depicts an organization where several processing units are managed by a single control unit. Although each processor works with a distinct portion of the data, they all receive the identical instructions from the control unit.

• These computers are extremely specialized. They are primarily applied to numerical issues defined as matrices or vectors. However, they are not appropriate for other kinds of calculations.

MISD (Multiple Instruction Stream, Single Data Stream)

• It is made up of one computer with several processors connected to several control units and a shared memory unit. 
• It has the ability to handle several commands over one data stream at once. 
• Since no actual system has been built using the MISD structure, it is only theoretically interesting.

MIMD (Multiple Instruction Stream, Multiple Data Stream

• It stands for the company that has the capacity to handle multiple programs at once. It is the arrangement of several processors connected to several control units and a shared memory unit within a single computer. 
• Multiple modules are present in the shared memory unit to enable simultaneous communication with all processors. Examples of MIMD include multiprocessors and multicomputer systems.