Process Creation in Operating Systems

Process Creation and Management

• fork() returns a process ID (PID) for the parent process, indicating the successful creation of a child process.
• The exit() system call terminates a process and frees up resources associated with it.
• The child process executes concurrently with its parent after the fork() call.
• The operating system uses process identifiers (PIDs) to identify and manage processes.

Process States and Transitions

• Process termination occurs when a process completes its execution or is forcibly terminated.
• The process table contains essential information about each process, such as the PID, state, memory allocation, and CPU scheduling data.
• The 'Suspended' state signifies that a process is temporarily halted but can be resumed.
• A 'Blocked' state occurs when a process cannot continue executing, typically waiting for resource availability.
• A process enters the 'Suspend Ready' state when it is ready to execute but has been suspended intentionally.
• Moving into the 'Suspend Wait' state happens when a process waiting for an event or resource is suspended.
• A process reaches the 'Terminated' state when it has completed execution or when it is explicitly killed.

Purpose and Tasks of Process Management

• Process creation serves the purpose of allowing multitasking and resource management in a system.
• Main tasks in process management include scheduling, resource allocation, and process synchronization.
• The operating system allocates memory that processes can share, facilitating data exchange.

Process Architecture

• The Text section in process architecture contains the executable code for the process.
• The newly created stage of a process in primary memory from secondary memory is called the 'New' state.
• A process state defines the current status of the process (e.g., running, waiting, suspended).

Operating System Responsibilities

• The operating system's main responsibility in managing processes is to ensure fair CPU time distribution and efficient resource management.
• A child process is created in an operating system via a fork() system call from the parent process.
• The relationship between a parent process and a child process is typically hierarchical, with the parent controlling the child's execution.
• When a new process is created, it receives its own Process Control Block (PCB) which includes relevant metadata.

Process Control Block (PCB)

• The PCB is allocated during process creation to maintain the execution context of each process.
• A unique Process Identifier (PID) is assigned to a new process to prevent conflicts and enable process management.
• Parent and child processes are managed in an operating system through the PCB, which tracks their state and resource usage.

Termination Conditions

• A child process can be terminated if the parent process ends or if it encounters a critical error.
• A process may be terminated for attempting to write into a read-only file due to violation of file system permissions.
• If a process requires more memory than is currently available, it may be terminated to prevent system instability.
• Child processes are often terminated when their parent is terminated to avoid orphan processes.
• I/O failures, such as device unavailable or errors in reading/writing, can result in the termination of a running process.