Difference Between Process and Thread

Difference Between Process and Thread

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Vikram
Vikram Singh
Assistant Manager - Content
Updated on Dec 22, 2023 17:04 IST

Confused about how your computer handles multiple tasks at once? Demystify the difference between processes and threads, the hidden engines driving parallelism on your machine. Learn how they share resources, handle tasks independently, and boost performance.

Difference between process and thread

Are you curious about how your computer or smartphone handles multitasking so seamlessly? If so, let's dive into the world of processes and threads in computing. These basic elements are more than just technicalities; they're the backbone of your favourite apps and software. This concise guide will unveil the hidden mechanics behind these everyday miracles. Get ready for an enlightening journey into the core of computing, where each thread weaves and each process shapes your digital experience.

Table of Content

  • Difference Between Process and Thread: Process vs Thread
  • What is Process?
    • Key Characteristics of Process
    • Real-life Application of Process
  • What is Thread?
    • Key Characteristics of Process
    • Real-life Application of Process
  • Case Study: The Web Browser Analogy

What is the Difference Between Process and Thread?

Aspect Process Thread
Definition An independent unit of execution containing its own memory space. A lightweight, executable unit within a process.
Memory Space Has its own separate memory space.  Shares memory space with other threads within the same process.
Overhead Higher overhead due to separate memory and resource allocation. Lower overhead, more efficient in resource usage.
Execution Operates independently. Depends on the process; multiple threads can run in parallel within one process.
Communication Communicates through IPC mechanisms. Communicates directly through shared memory.
Control Can be started, stopped, and controlled independently.  Controlled within the context of a process.
Resource Allocation Each process has its own resources (files, variables, etc.). Share resources of the process they belong to.
Isolation Processes are isolated from each other.  Threads can directly affect each other within the same process.
Failure Impact Failure in one process does not affect other processes.  A failure in one thread can affect all threads of the process. 
Creation Time Longer creation time due to resource allocation. Shorter creation time since less resource allocation is needed.
Use Case Suitable for applications needing isolated execution.  Ideal for tasks requiring frequent communication and shared resources.
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What is Thread? 

A thread is a set of code running within a process that keeps track of its location in memory to pick up where it left off the next time it is called. This is a lightweight process that does the same job as a process.

Threads are how the operating system handles multiple tasks running simultaneously. In an ideal world, an operating system could handle all these tasks simultaneously, but that’s not always possible. All running programs are linked. That is, everything runs in parallel. This allows programs to work together as a team rather than against each other.

Example of Thread 

When working with large amounts of data. If you try to open the files simultaneously, it may take a long time. Threads allow you to split the data into pieces and open them parallelly. This way, the program can be completed much faster.

Application of Thread

  • While the movie plays on the device, various threads control the audio and video in the background.
  • While Downloading videos, if you are playing video games at the same time, that indicates multi-threading.
  • When processing data in a database, threads can be used to process the data cooperatively. In this scenario, data is written to the database in parallel, and threads read the data back.
  • Download files and view them at the same time. So, it is possible as threads are working behind it.

What is a Process?

A process is essentially an instance of a computer program that is currently being executed. It comprises the program code and its current activity. It is worth noting that each process has its own separate memory address space, meaning that it operates independently and remains isolated from other processes. Processes can communicate with each other through inter-process communication (IPC) mechanisms.

Key Characteristics of Process

  • Independence: Each process operates independently and has a dedicated set of resources. 
  • Memory Allocation: Every process has its separate memory space, which is not shared with any other process. 
  • Communication: Processes communicate with each other using IPC mechanisms like pipes, sockets, and shared memory. 
  • Overhead: Creating a new process is resource-intensive since it requires allocating memory and other resources.

Applications of Process

  • Launch your browser if you want to search for something on the web. So, this can be process.
  • The process can start when launching a music player and listen to some cool music of your choice.
  • When antivirus is running, it is a process.
  • When you compile a program in C or C++, the compiler creates binary code. Both original code and binary code are programs. When you actually run the binary it becomes a process.

Key Differences Between Process and Thread

  • A process is an active program, i.e., a program that is under execution. Threads are lightweight processes that can be managed individually by a scheduler. It is more than program code; it contains program counter, process stack, registers, and program code. 
  • Threads share information, such as data segments, code segments, files, etc., with peer threads while using their registers, stacks, counters, etc. 
  • No other process can run once a process is blocked until the first one is unblocked. While one thread is blocked waiting, a second thread may be running on the same task.
  • The process takes more time to complete and is isolated. That is, it does not share the memory with other processes. Threads take less time to complete than processes, but unlike processes, threads are not isolated.
  • A thread is a sequence of instructions that runs in the same context for the whole process. Each running thread consumes less memory than the process because each thread occupies just one bit of memory space. On the other hand, a process can contain multiple threads, which consumes more memory per thread than one thread alone would. 

Conclusion

A process is an active entity, unlike a program, which is considered a “passive” entity. Attributes held: A thread is a sequence of instructions that runs in the same context for the whole process. Each running thread consumes less memory than the process because each thread occupies just one bit of memory space. A process can contain multiple threads, which consumes more memory per thread than one thread alone would.

FAQs on the Difference Between Process and Thread

What is a Process in Computing?

A process is an independent unit of execution in computing, containing its own memory space and executing its own program code.

What is a Thread?

A thread is a lightweight, executable unit within a process, sharing the process's memory space but maintaining its own execution sequence.

How Do Processes and Threads Differ in Memory Allocation?

Processes have their own separate memory space, whereas threads share the memory space of their parent process.

Can Threads Operate Independently of Processes?

No, threads depend on the process and cannot exist outside of it. They are controlled within the context of a process.

How Do Processes and Threads Communicate?

Processes communicate through inter-process communication (IPC) mechanisms, while threads communicate directly through shared memory within the same process.

What Happens if a Thread Fails?

A failure in one thread can potentially affect all threads within the same process, as they share the same memory space.

Which is Faster to Create: a Process or a Thread?

Creating a thread is generally faster than creating a process, as threads require less resource allocation.

When Should I Use a Process Over a Thread?

Processes are more suitable for tasks that require isolated execution environments, while threads are better for tasks that require frequent communication and shared resources.

Can a Single Process Have Multiple Threads?

Yes, a single process can have multiple threads, which can run in parallel, sharing the process's resources but maintaining separate execution sequences.

What is the Overhead Difference Between a Process and a Thread?

Processes have a higher overhead due to separate memory and resource allocation, while threads have lower overhead, making them more resource-efficient.

About the Author
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Vikram Singh
Assistant Manager - Content

Vikram has a Postgraduate degree in Applied Mathematics, with a keen interest in Data Science and Machine Learning. He has experience of 2+ years in content creation in Mathematics, Statistics, Data Science, and Mac... Read Full Bio