A Hardware Abstraction Layer (HAL) is a software layer that provides a simplified interface between the operating system and the hardware components of a computer or device. It allows the operating system to interact with various hardware without needing to know the specifics of each device. This abstraction helps in making software more portable and easier to develop, as developers can write code that works across different hardware platforms. By using a HAL, changes or upgrades to hardware can be made with minimal impact on the software. For example, if a new type of graphics card is introduced, the HAL can manage the differences, allowing existing applications to run without modification. This separation of concerns enhances system stability and flexibility.