Message (computer science) facts for kids

In computer science, a message is like a digital note or a small package of information. It's a bit of data that one part of a computer system, called the sender, sends to another part, called the recipient. Think of it like sending a text message to a friend, but instead of people, it's computer programs or different parts of a computer talking to each other. This usually happens by making a copy of the data and sending it along. When the recipient gets the message, it often reacts in a specific way, especially in systems that respond to events.

What is a Computer Message?

A computer message is a small piece of data or information. It's designed to be sent from one place to another within a computer system. This could be between different programs, different parts of a program, or even between computers over a network. Messages are how different parts of a computer communicate and work together. They are essential for almost everything a computer does.

How Do Computers Send Messages?

When a computer sends a message, it typically makes a copy of the data. This copy is then sent to the recipient. The original data might stay with the sender. This process is very fast. It allows information to travel quickly. It also ensures that many parts of a system can share information.

Senders and Receivers

Every message needs a sender and a receiver. The sender is the part of the computer that creates and sends the message. The receiver is the part that gets the message. For example, when you click a button on a screen, the button (sender) might send a message to the program (receiver). This message tells the program that the button was clicked.

Different Kinds of Computer Messages

Messages come in many forms. Their purpose depends on what they need to do. Some messages carry simple data. Others are more complex. They might tell a program to do something specific.

Messages in Programs

Inside a single computer program, messages help different parts talk. For instance, in a video game, pressing a key sends a message. This message tells the game character to move. In object-oriented programming, objects send messages to each other. These messages ask objects to perform actions. This helps programs stay organized.

Messages Across Networks

Messages are also vital for computers connected over a network. When you send an email, it's broken into many small messages. These messages travel across the internet. They are then put back together by the recipient's computer. Websites, chat apps, and online games all use messages. They send information back and forth. This allows you to interact with people and services worldwide.

How Messages Make Things Happen: Event-Driven Systems

Many computer systems are event-driven. This means they wait for something to happen, an "event," before they do anything. Messages are key to how these systems work.

What is an Event?

An event is something that happens. It could be a user clicking a mouse. It could be a key being pressed. It could also be data arriving from the internet. When an event occurs, it often creates a message. This message describes what happened.

Messages and Events Working Together

In an event-driven system, when an event happens, a message is sent. This message goes to a specific part of the program. The program then "listens" for these messages. When it receives a message, it knows what event occurred. Then, it performs an action based on that message. For example, clicking a "Save" button sends a message. The program receives this message. It then saves your work. This makes programs responsive and interactive.

Messages in Your Daily Life

You use computer messages all the time, even if you don't realize it. They are behind many common activities.

Sending an Email or Chat

When you send an email or a message on a chat app, your computer creates a message. This message contains your text and who it's for. It then sends this message over the internet. The recipient's computer receives it. It then shows your message.

Browsing the Internet

When you type a website address into your browser, your computer sends a message. This message asks the website's server for information. The server then sends back messages. These messages contain the website's content. Your browser uses these messages to display the page.

Playing Video Games

Every time you press a button on your game controller, it sends a message. This message goes to the game console or computer. The game receives this message. It then makes your character jump, run, or attack. Messages make games interactive and fun.