The Linux Tree of Processes

Process in Computer Science

• A process is a program in execution, with its own memory space and system resources.

Multiprogramming

• The purpose of multiprogramming is to improve CPU utilization by executing multiple programs concurrently.

Process Creation in Linux

• When creating a new process, the parent process creates a copy of itself and the new process gets a copy of the parent's memory space.

Process Creation and Termination

• After the OS decides to create a new process, it allocates memory and resources, and initializes the process control block (PCB).
• When a process terminates, the OS reclaims its resources, and the memory space is deallocated.

Inter-Process Communication (IPC)

• The purpose of IPC is to enable communication between multiple processes to exchange data and synchronize their actions.
• IPC can be achieved through message passing, shared memory, and synchronization.

Properties of a Communication Link

• A communication link can accommodate messages of fixed or variable size.
• A link can be unidirectional or bi-directional.

Buffering

• Buffering is a technique used to handle the transfer of data between processes.
• Buffering can be implemented using a fixed-size buffer, a dynamic buffer, or a circular buffer.

Memory Map

• The data section of an executable file's memory map contains global variables.

Process States

• A process enters the waiting state when it is waiting for some event to occur.
• A process enters the terminated state when it has finished executing.

Process Control Block (PCB)

• The PCB is used by the OS to keep track of processes.
• The PCB contains information such as process ID, memory pointers, open files, and CPU registers.

Process Execution

• A process needs resources such as CPU time, memory, and I/O devices to execute.
• The OS plays a crucial role in assigning resources to processes.

Programs vs. Processes

• A program is a set of instructions, while a process is a program in execution.

Context Switching

• Context switching is the rapid switching back and forth of the CPU between processes.
• It involves saving the current state of the process and restoring the state of the newly scheduled process.

PCB Elements

• The PCB includes elements such as process ID, memory pointers, open files, CPU registers, and accounting information.
• The CPU registers in the PCB contain the current state of the process.

Process Termination

• When a process is terminated, its resources are deallocated, and the memory space is released.

Memory Management

• The memory-management information in the PCB includes information about the process's memory usage.

Accounting Information

• The accounting information in the PCB includes information about the process's resource usage.

Message Passing

• Message passing is a method of IPC where processes exchange data through messages.
• Message passing can be implemented using direct communication, indirect communication, or mailbox sharing.

Direct Communication

• In direct communication, the sending process knows the name of the receiving process.

Indirect Communication

• In indirect communication, the sending process does not know the name of the receiving process.

Mailbox Sharing

• In mailbox sharing, a shared mailbox is used for communication between processes.

Synchronization

• Synchronization is used to coordinate the actions of multiple processes.

Blocking Send

• In blocking send, the sending process is blocked until the message is received.

Non-Blocking Receive

• In non-blocking receive, the receiving process continues to execute even if no message is available.

Buffering in Message Passing

• Buffering is used to handle the transfer of data between processes in message passing.

Process Scheduling

• The purpose of process scheduling is to allocate the CPU to different processes.

Process Scheduler

• The process scheduler is responsible for selecting the next process to run and allocating the CPU resources.

Test your knowledge about the tree of processes in Linux with this quiz. Learn about how parent processes create children processes and how they are identified and managed through process identifiers. Challenge yourself to identify the correct process identifiers for various processes in a given scenario.