Interface (computing) facts for kids

An interface is like a meeting point where different parts of a computer system talk to each other. It's how they share information. This can happen between software programs, computer parts (hardware), devices you plug in (peripherals), or even between you and the computer!

Some devices, like a touchscreen, can both send and receive information through their interface. Others, like a mouse or microphone, mainly send information to the computer.

Hardware Interfaces

Hardware interfaces on a Laptop: The Ethernet port (center) connects to networks. Other ports include VGA, display port, and USB.

Hardware interfaces are found in many computer parts. Think of them as the physical connections that let different pieces of hardware work together. This includes things like the buses inside your computer, storage devices, and other input/output (I/O) devices.

A hardware interface is defined by its physical shape, electrical signals, and the rules (called a protocol) for how data is sent. Having standard interfaces, like SCSI, makes it easy to connect different devices. This means manufacturers can create new hardware without having to redesign the whole computer system.

Hardware interfaces can be parallel, sending many bits of data at once. Or they can be serial, sending data one bit at a time.

Software Interfaces

A software interface is how different computer programs or parts of a program communicate. It's like a set of rules that programs follow to interact.

For example, your computer's operating system needs to talk to the hardware. Also, different applications running on your computer might need to share data. Even within one program, different sections might need to exchange information.

Why Software Interfaces are Important

A key idea in computer design is to control access to computer resources. This means programs should only be able to use things like memory or the processor through specific, well-defined interfaces.

If programs could directly access these resources without proper interfaces, it could cause big problems. Your computer might crash or not work correctly. Software interfaces act like gatekeepers, making sure everything runs smoothly and safely.

These interfaces define what information can be shared. They specify things like the types of data, the procedures programs can use, and how to handle errors. Sometimes, shared variables are also part of an interface.

How Software Interfaces Work

The interface of a software part is kept separate from its actual inner workings. The inner workings contain the real code that does the job. Other software parts that want to use this part must only do so through its public interface.

This is very useful! If the way a software part works internally changes, other parts that use it won't be affected. As long as the interface stays the same, the other parts will still be able to communicate. It's like knowing how to use a remote control without needing to know how the TV works inside.

Interfaces in Object-Oriented Programming

In some programming languages, an interface is a special type of blueprint. It doesn't contain any actual code or data itself. Instead, it defines a set of actions (called methods) that a program part can perform.

A class (which is like a blueprint for creating objects) can then "implement" an interface. This means the class provides the actual code for all the actions defined in that interface.

One big advantage is that a class can implement many different interfaces. This allows a single object to act like different types of things at the same time. For example, an interface called "Stack" might define two actions: push() (to add something) and pop() (to remove something). Different classes could implement this interface in various ways, like a FastStack (for speed) or a GenericStack (for flexibility).

Sometimes, an interface might not define any actions at all! These are called marker interfaces. They simply tell the computer something special about the program part. For example, the Java language has a Serializable interface. It tells the system that an object can be saved and loaded.

Programming to the Interface

Using interfaces leads to a programming style called programming to the interface. This means you write your code to work with the general rules of an interface, not with the specific details of how something is built.

This makes your code more flexible and easier to reuse. It reduces how much your code depends on specific implementations. It's like designing a car to use "a wheel" rather than "this specific brand of wheel." Any wheel that fits the interface will work.

User Interfaces

A user interface is the point where you, the human, interact with a computer. It includes everything you use to give commands and receive information. This can be graphics on a screen, sounds, movements, or even your voice. It's how data moves between you and the computer system.

See also

• Abstraction inversion
• Application binary interface
• Application programming interface
• Business Interoperability Interface
• Computer bus
• Hard disk drive interface
• Implementation (computer science)
• Implementation inheritance
• Interoperability
• Inheritance semantics
• Modular programming
• Software componentry
• Virtual inheritance