How do I change the hard drive from PIO mode to DMA mode?

1. Right-click My Computer to select Properties, and then select Device Manager under the Hardware tab:

2. Expand the IDE ATA/ATAPI controller node;

3. Double click on your "Primary IDE controller";

4. Click "Advanced Settings" and change to DMA

The following is a detailed analysis of the hard disk DMA mode and PIO mode.

The English spelling of DMA is "direct Memory access" (memory is accessed directly). This refers to a high-speed data transfer operation that allows data to be read and written directly between external devices and memory, neither through the CPU nor CPU intervention. The entire data transfer operation is performed under a control called a "DMA controller". The CPU can do other work in the process of transferring, in addition to doing some processing at the beginning and end of data transmission. In this way, for most of the time, the CPU and the input and output are in parallel operation. Therefore, the efficiency of the whole computer system is greatly improved.

(ULTRA-DMA/33), 1996 by the Intdl and quantum developed a data transmission mode, this way I/O system burst data transmission speed of up to 33mb/s, can also reduce the I/O system to the CPU resource occupancy rate. Now there is a udma/66, twice times more speed.

Pio's English spelling is "programming Input/output model", and PIO mode is a data interchange mode that uses CPU to execute I/O port directives to read and write data. Is the most previous hard disk data transfer mode, low data transfer rate, CPU share is very high, a large number of data transfer because of excessive CPU resources and cause system pauses, can not do other operations. The PIO Data mode is divided into PIO mode 0, PIO Mode 1, PIO mode 2, PIO mode 3, PIO mode 4, and data transfer rates range from 3.3mb/s to 16.6mb/s. Constrained by low transmission rates and extremely high CPU occupancy, this data transfer pattern was quickly eliminated.

How do I use the DMA mode for the disk? Use the Hdparm tool to view:

For example, when we view the disk cache, the following error occurs:

[cnangel@cadev03 ~] $sudo hdparm-i/DEV/SDA

/DEV/SDA:

Hdio_get_identity failed:invalid argument

Prohibit the use of DMA mode:

[cnangel@cadev03 ~] $sudo HDPARM-D0/DEV/SDA

/DEV/SDA:

Setting USING_DMA to 0 (off)

HDIO_SET_DMA failed:invalid argument

Because the DMA mode of the hard disk is not turned on by default after the system is installed, the general method is to add a line to the/etc/rc.d/rc.local:

/sbin/hdparm-d1-c3-m16/dev/sda

So each time the boot, the hard drive DMA will be turned on, do not have to manually set each time.