"computer program consists of instructions and data on which the instruction operates. How are these instructions of a program executed by a computer? Where are these instructions and data stored during execution? What is the role played by Input/output devices? "

A computer program consists of a set of instructions and data that tell a computer what to do and how to do it. When a program is executed, the central processing unit (CPU) of the computer reads and interprets these instructions sequentially, one after the other. The CPU fetches each instruction from the computer's memory, decodes it to understand the operation to be performed, executes the operation, and stores the result back in the memory.

During execution, both the instructions and the data used by these instructions are stored in the computer's memory (RAM - Random Access Memory). RAM is a volatile memory, meaning it loses its contents when the computer is powered off. Instructions are fetched from the program stored in the computer's storage (such as a hard drive or SSD) and loaded into the RAM for execution. Similarly, the data required by the program, as well as the intermediate and final results of computations, are also stored in RAM.

Input/output (I/O) devices play a crucial role in the execution of computer programs. These devices, such as keyboards, mice, monitors, printers, and storage devices, allow the computer to interact with the external world. Input devices enable users to provide data and instructions to the computer, such as typing text or clicking a mouse. Output devices display the results of computations, such as text, images, or videos, and allow users to perceive the output. Storage devices are used to store programs, data, and other files for long-term use, even when the computer is powered off.

During program execution, input devices facilitate the input of data and instructions into the computer, which are then processed by the CPU according to the program's instructions. The output devices display the results of the program's execution, allowing users to see the outcomes. Additionally, I/O devices can be used to read from and write to external storage devices, enabling programs to store and retrieve data for various purposes.

In summary, the CPU executes program instructions by fetching them from the computer's storage, loading them into RAM, interpreting and processing the instructions, storing data in RAM during the process, and using input/output devices to interact with users and the external world. This seamless coordination of components allows a computer to execute complex tasks and run a wide variety of applications and software programs.