Homework / test English to Polish Tech/Engineering Computers: Hardware

"bus muster" to z tego co mi wiadomo moduł nadrzędny magistrali, ale czy istnieje coś takiego jak modułowanie/modulowanie nadrzędnej magistrali? Dla mnie brzmi to trochę dziwnie.
Tekst dotyczy CPU

"In the past, the CPU controlled the data transfer between the hard disk drive and the RAM memory. Since the hard disk drive is slower than the RAM memory, this slowed down the system, since the CPU would be busy until all the data was transferred from the hard disk drive to the RAM memory. This method is called PIO, Processor I/O (or Programmed I/O). Nowadays data transfer between the hard disk drive and the RAM memory in made without using the CPU, thus making the system faster. This method is called bus mastering or DMA (Direct Memory Access). In order to simplify our drawing we didn’t put the north bridge chip between the hard disk drive and the RAM memory in Figure 1, but it is there."