AHCI in SATA Mode

If you buy a hard disk, most of them look at the brand and capacity. If you have some knowledge about the hard disk, you may consider a hard disk with a larger single disk capacity. This is basically a matter of consideration. Then, after the purchase, connect to the SATA port and start partitioning and formatting, and then install the system for use. This is almost the way most people use hard disks.
When purchasing the product, I may ask at the Forum: Is Seagate better or Western data better? Seagate's three yellow doors. What is the firmware door? Is Seagate's hard drive worth buying? Is it because western digital technology is not in place, so there are few single-disc 1 TB? I even asked, is it because the 808.8G product of Western Digital cannot be sold again?

After these problems are solved, some friends have chosen the hard disk and left after they have bought it. At most, you can test the disk speed and view the hard disk curve. In fact, even the aforementioned "homework" are rarely considered. The most common practice is: Boss, I need a GB hard disk.
In fact, hard disks are not what you think. Just plug in and use them. If you want to enjoy the improved technology and performance brought about by the technological development, you must set them by yourself, and enable the advanced features of the hard disk. So today, let's talk about what are the advanced features of the hard disk and how to enable the advanced features of the hard disk.
　　
A hard disk stores information by writing information to a specific location on the disk track. Therefore, the access sequence is as follows: first, find the target disk (platter) for storing data and access the disk. Then, find the target track for storing data on the disk to access the track. Find the target cluster for storing data on the track and access the cluster. Find the target sector for storing data on the cluster and access the sector. Search for the target data and read the data.
To put it simply, disk-track-target cluster-target sector-read data.

Winchester hard drive
As for hard disk writing, this mode is also used. However, the disk data is not recorded in order. For example, in a game, thousands of files are also allocated to different disks, and a file may be allocated to different slices and clusters. For example, if you want to read a file, you may first read the 432 sector of Disk 1, then read the 812 sector of Disk 2, and then jump to disk 1 to read the 665 sector, this is a waste of time. There is another problem: reading a file is so troublesome. Isn't it necessary to read multiple files at the same time to play a game?
Indeed, this is a mechanical hard disk and has become a major drawback of the Winchester hard disk. Because the hard disk is read mechanically, the head needs to keep beating on the disk to read data. This irregular beating directly affects the speed at which the disk reads scattered files. In this regard, you may have some feelings: copying a huge ISO file may be 120 M/second, but copying a M scattered folder may be two or three minutes. Although the large ISO files are not arranged in order, their regularity is relatively high.
As long as it is a mechanical hard disk, this problem cannot be solved, so solid state disks become the pursuit of performance updates. However, SSD capacity is not high, and the price is exaggerated, so it cannot be popularized. In this case, the sata ii specification provides a compensation mechanism, or an advanced feature: NCQ. This NCQ technology requires AHCI.
　　
With the development of hard drive technology, many new technologies have emerged. When a single disk is GB towards GB, the application of vertical record increases the disk capacity per unit volume. The SATA interface hard disks that appeared earlier are constantly being upgraded. New technologies provide more powerful support for hard disks and new functions are emerging, it also provides the NCQ and hot swapping functions.

　NCQ is called "Native Command Queuing, NCQ )". Full-speed command queue is the most advanced and expected feature of sata ii. It is an important part of the sata ii specification and the only technology related to hard disk performance. NCQ is a powerful interface/hard disk technology. It improves hard disk performance and service life by optimizing the execution sequence of jobs inside the hard disk.
Commands received by hard disks supporting NCQ are rearranged according to the distance of the addresses they access. In this way, intelligent internal management is implemented for the implementation of Hard Disk mechanical operations, greatly improve the efficiency of the entire workflow: extract the commands in the queue, and then re-
In order to effectively obtain and send host request data, while executing a command on the hard disk, new commands can be added to the queue side by side in the jobs waiting for execution. Obviously, after the command arrangement, the time for the head arm to move back and forth is reduced, Making Data Reading more effective.
If you perform a series of reads on the hard disk, because the data distribution on the disk is different, when the NCQ technology is not enabled, the head may first read 78 sectors of disk Disk 1, read the 760 sector of Disk 2, then read the 261 sector of Disk 1, and then read the 43 sector of Disk 2. However, if NCQ is enabled, data of Disk 1 will be read first, for example,-sectors, and then read from the 43-760 sector in the jump to Disk 2. This effectively reduces the disk jump frequency and increases the reading speed of small files.
　　
As mentioned above, NCQ is actually a meaningful new hard disk feature. But Will NCQ be enabled as long as it is a hard disk that supports NCQ? This is almost impossible. Because the hard drive enables NCQ technology, you must enable AHCI In the BIOS, and some chipsets must be configured in the system. This involves the support of the Motherboard chipset. Generally, most of the current P43, P45, NVIDIA motherboard, and AMD mainstream chipset support the AHCI function, however, we recommend that you read the motherboard manual.

AHCI motherboard not enabled
Almost all the mainboards. By default, the interface mode of the hard disk is IDE. Although it is a SATA interface hard disk, to ensure compatibility, the motherboard treats them as IDE devices for data processing. This can be seen from our figure: the Device Manager contains a large number of IDE devices.
After being recognized as an IDE device, the NCQ and hot swapping technologies are lost. performance and speed will be treated as an IDE device in a regular manner. Although the reading and transmission speeds of most hard disks can be met in IDE mode.

After AHCI is enabled, there are only two native IDE Channels
For the following content, refer to Baidu: AHCI, all called Serial ATA Advanced Host Controller Interface (Serial ATA Advanced control Interface/Advanced Host Controller Interface). It is under Intel's guidance, API standards jointly developed by multiple companies, which allow storage drivers to enable advanced Serial ATA functions, such as local command queues and hot swapping, its R & D team members mainly include Intel, AMD, Dell, Marvell, Alto, Microsoft, Red Hat, Seagate, StorageGear and other famous enterprises.
AHCI is essentially a PCI device, it acts as a common interface between the system memory bus and the internal logic of the Serial ATA device (that is, it is common in different operating systems and hardware ). This type of device describes a general system memory structure with control and status areas and command sequence entry tables. Each Command table entry contains SATA device programming information, and a pointer to the description table (used to transmit data on devices and hosts.
Simply put, when we enable the AHCI function, the management of the hard disk is transferred to the AHCI module and driver for control. In this state, the NCQ and hot swapping functions can be enabled.
　　
The AHCI driver module is different from the general IDE driver module. Therefore, if the system has been installed and changed in the BIOS, the system cannot be entered. So if you are a new installation system user, you can check this page.
　　
　　

First, we need to enable the AHCI function in the BIOS. Select AHCI as shown in. Press F10 or another save shortcut, save the BIOS, and restart.

Take VISTA as an example (also applicable to Windows 7). In the installation process, select a new installation, and then select "load driver" on the hard disk partition interface to find the originally placed driver, if the 32-bit system is installed, select the X86 folder. If the 64-bit system is installed, select the X64 folder. Click OK to wait for driver installation. After the installation is complete, the normal partition enters the system.
Note:
1: The above method is only applicable to INTEL and AMD chipset, while the NVIDIA chipset motherboard only needs to load a special driver in the system, so the NVIDIA chipset to enable AHCI method will be detailed on the next page.

2: AMD RAIDXpert needs to be installed on the AMD chipset. When you enter RAIDXpert, the default account password is admin. Find "physical disk View" and select the corresponding hard disk, select enable NCQ in the settings option and click "send.
Because the driver module is different, only the options in the BIOS are changed, then the operating system cannot load the AHCI module and thus crash. Therefore, we must make some changes in the operating system. The following description is applicable to VISTA and Windows 7. Note: The following steps apply only to INTEL and AMD chipset.

VISTA and Win7 System 1: type the regedit command in "run", find HKEY_LOCAL_MACHINE \ System \ CurrentControlSet \ Services \ Msahci, and double-click "Start" in the "name" column ", in the value data box, type "0", and then confirm and exit the Registry Editor.
2: Change the options in the BIOS to AHCI and save the settings as described above.
3: after entering the system, new hardware will be found. For AMD chipset users, manually select the amd ahci driver and install it. After installation, restart and install AMD RAIDXpert. When you enter AMD RAIDXpert, the default account password is admin. Find "physical disk View" and select the corresponding hard disk, select enable NCQ in the settings option and click "send. For INTEL chipset users, manually install Intel Matrix Storage Manager.
　　
AHCI functional performance Q &
Q: Can AHCI increase the hard drive speed?
A: AHCI is not a function that can increase the disk speed. Therefore, even if it is enabled, it may not show any advantages in the disk read/write speed test. As mentioned above, AHCI optimizes the read/write sequence to a greater extent, reducing the time needed to read a large number of scattered files.
Q: Why do I feel that the XP scroll bar turns several more times when I enable AHCI?
A: After AHCI is enabled, the system will wait a little longer when it enters the scroll bar. Because AHCI is loaded as a management module, it is a little slower than the normal IDE mode. However, after entering the system, it can reflect its advantages.
Q: What should I do if the above techniques are applicable to AMD and INTEL chipset?
A: Most NVIDIA chipsets do not use BIOS to implement AHCI. In the NVIDIA chipset's built-in driver, there is an ide sw driver. Install this driver to enable AHCI.
Note:

Supported but not enabled AHCI
Hard drive support for AHCI and AHCI are completely different concepts. The hard disk supports AHCI. After hd tune is enabled, we can check some options in "supported features.

Enable AHCI
However, after AHCI is enabled, the supported feature options will change to a filled blue lattice, which means that AHCI is actually enabled. In this status, the disk information and standards are as follows, and the health is invisible.