COMPUTER FUNDAMENTALS

Detailed explanation-1: -A single processor can run only one instruction at a time: it is impossible to run more programs at the same time. A program might need some resource, such as an input device, which has a large delay, or a program might start some slow operation, such as sending output to a printer.

Detailed explanation-2: -Computers can only do one task (or process) at a time. But a computer can change tasks very rapidly, and fool slow human beings into thinking it’s doing several things at once. This is called timesharing. One of the kernel’s jobs is to manage timesharing.

Detailed explanation-3: -In the case of a computer with a single CPU core, only one task runs at any point in time, meaning that the CPU is actively executing instructions for that task.

Detailed explanation-4: -In a single core system, the OS allows multiple processes to run by sharing CPU time with the multiple processes. This is called concurrency, which gives the illusion of multiple processes executing at once, but is in fact just using a scheduler to give each process dedicated time on the CPU.