The size of the data count register of a DMA controller is 16 bits. The processor needs to transfer a file of 29,154 kilobytes from disk to main memory. The memory is byte addressable. The minimum number of times the DMA controller needs to get the control of the system bus from the processor to transfer the file from the disk to main memory is _________.

1. Maximum Data Transfer per DMA Operation: The data count register of the DMA controller has a size of 16 bits. Since the memory is byte addressable, a 16-bit register can count up to:

   $$2^{16} = 65,536\text{ bytes} = 64\text{ KB}$$

2. Total File Size to be Transferred:

   $$\text{File Size} = 29,154\text{ KB}$$

3. Minimum Number of DMA Transfers:

   $$\text{Number of transfers} = \left\lceil \frac{29,154\text{ KB}}{64\text{ KB}} \right\rceil = \lceil 455.53125 \rceil = 456$$

Each DMA transfer requires obtaining control of the system bus from the processor once. Therefore, the DMA controller needs to get control of the system bus a minimum of 456 times.