The virtual OS instance can access the mounted file systems without any issues, but direct mounting from OS instance is not possible.
虚拟OS实例可以正常访问挂载的文件系统，但是无法直接从OS实例挂载文件系统。
2
The first copy (see Figure 1) is performed by the direct memory access (DMA) engine, which reads file contents from the disk and stores them into a kernel address space buffer.
This paper introduces the design & implementation of a parallel file system based on direct data access, and gives out the primary functions and key technologies of parallel file system.