In computer science, a process is an instance of a program that is being executed by the operating system. A process consists of a program code, data, and resources such as open files, sockets, and memory. Processes are managed by the operating system and have their own process control blocks (PCBs), which are data structures that contain information about the process, such as its current state, program counter, and memory allocation.
The PCB is used by the operating system to keep track of the state of each process and to switch between them when necessary. The PCB is created by the operating system when a new process is created and is updated as the process runs. The PCB contains information about the process, such as its priority, memory allocation, and state.
The steps performed by an operating system to create a new process typically include:
1. Allocating memory for the new process.
2. Setting up the process control block for the new process.
3. Initializing the program counter and other registers.
4. Setting up the initial stack.
5. Setting up the process's environment variables and command-line arguments.
6. Loading the program code and data into memory.
7. Starting the new process.
For example, when a user opens a web browser, the operating system creates a new process to run the browser program. The operating system allocates memory for the process, sets up the process control block, initializes the program counter and other registers, loads the browser code and data into memory, and starts the process. As the process runs, the operating system updates the process control block with information about the process, such as its current state and memory usage.