各种商用实时操作系统，都采用了分层设计的方法，它将系统中与硬件直接相关的一层软件独立出来，称之为Board Support Package即简称BSP。顾名思义，BSP是针对某个单板而设计的，并且它对于用户（指开发者）也是开放的，用户可以根据不同的硬件需求对其作改动或二次开发，而操作系统本身仅仅提供了CPU内核的无关性。BSP在系统中的角色，很相似于BIOS在PC系统中的地位。-A variety of commercial real-time operating systems, have adopted a layered design approach, which is directly related to the system and hardware independent software layer, called the Board Support Package that is referred to as the BSP. As the name suggests, BSP is designed for a single board, and it is for the user (referring to the developer) is open, the user needs according to different hardware or to make changes to its secondary development, and the operating system itself provides only the CPU kernel-independent. BSP' s role in the system, very similar to the system BIOS in the PC position.