In a portable FireWire compatible device, a direct memory access (DMA) bus switch coupled by way of a DMA bus to a central processing unit (CPU), a local hard drive (HDD), and a FireWire port, provides a direct connection between the FireWire port and the HDD bypassing a main bus and the CPU when a data transfer request is received and processed by the CPU. Otherwise, until the data transfer request is received and processed, the CPU is directly connected to the HDD. In this way, a high speed data transfer between the FireWire port and the HDD is provided only when an appropriate data transfer request is received and processed.