One of the IDE hard drives in a server is transferring data very slowly. What command must be

run to enable DMA on it?

A.
hdparm -d /dev/hda

B.
hdparm –dma /dev/hda

C.
hdparm –dma /dev/hda1

D.
hdparm -d /dev/hda1

E.
hdparm -d1 /dev/hda

Explanation:

hdparm provides a command line interface to various kernel interfaces supported by the Linux
SATA/PATA/ SAS “libata” subsystem and the older IDE river subsystem. Many newer (2008 and
later) USB drive enclosures now also support “SAT” (SCSI-ATA Command Translation) and
therefore may also work with hdparm. Eg. recent WD “Passport” models and recent NexStar-3
enclosures. Some options may work correctly only with the latest kernels.
-d Disable/enable the “using_dma” flag for this drive. This option now works with most
combinations of drives and PCI interfaces which support DMA and which are known to the kernel
IDE driver. It is also a good idea to use the appropriate -X option in combination with -d1 to ensure
that the drive itself is programmed for the correct DMA mode, although most BIOSs should do this
for you at boot time. Using DMA nearly always gives the best performance, with fast I/O
throughput and low CPU usage.