Nineth Chapter: Hardware Abstraction Layer: HAL

The hardware abstraction layer is the interface layer between the operating system kernel and the hardware circuitry, which is designed to abstract the hardware. It hides the hardware interface details of a particular platform, providing the operating system with a virtual hardware platform that is hardware agnostic and can be ported across multiple platforms. From the point of view of hardware and software testing, the test work of hardware and software can be done separately based on the hardware abstraction layer, which makes it possible to parallel the hardware and software testing work.
The hardware abstraction layer is a programming layer that allows computer operating systems to interact with hardware devices at the logical layer rather than at the hardware level. Windows 2000 is one of the operating systems that support the hardware abstraction layer. The hardware abstraction layer can be called by either the operating system core or the hardware driver. In either case, the calling program does not need to know the specifics of the hardware design, only the parameters required by the abstraction layer. [1]?
Characteristics
* Hardware abstraction layer has close correlation with hardware
* Hardware abstraction layer with OS agnostic
* The features defined by the interface should contain all the features required by hardware or system hardware support
* Interface definition is straightforward, too many interface functions add complexity to software simulations
* Measurable interface design facilitates system hardware and software testing and integration
Working mode
The hardware abstraction layer to the user device interface function simulation mainly by the virtual driver module, including the data packet Transceiver and protocol message preprocessing and so on, for the upper layer protocol software to provide standard API functions, and the user device interface management by the upper layer network management software through the Management module management system to manage its configuration and monitoring, The internal communication module runs in the internal team Ethernet network and coordinates the functional interface between the modules, ensuring real-time and reliable data transfer between the processing unit and the main processing unit.

Nineth Chapter: Hardware Abstraction Layer: HAL