Difference Between AHCI and SATA

An interface is a kind of shared medium through which the components of a computer system exchange information. In an operating system, a software interface may refer to a different range of applications or programs, which run via data streams, pipelines, and filters. Two of these interfaces in operating systems are the Advanced Host Controller Interface (AHCI) and Serial Advanced Technology Advancement (SATA).

AHCI vs SATA

The main difference between AHCI and SATA is that AHCI is a newer programming interface that adds extra functionalities. It is an updated version of SATA. SATA, on the other hand, is a computer bus interface that was designed to replace the Parallel Advanced Technology Attachment (PATA) and provide a better speed than the previous one.

The Advanced Host Controller Interface (AHCI) is an Intel-designed host controller interface that adds extra functionalities. It was designed as an updated and newer version of SATA. It allows access to the indigenous functions of the SATA interface such as Native Command Queuing (NCQ) and hot-plugging. Being a bit more advanced, AHCI might be difficult for the motherboard to adapt to the drive.

While, the Serial Advanced Technology Attachment (SATA) is a newer computer bus interface designed to overtake the older version of Parallel Advanced Technology Attachment (PATA). These hosts and controllers communicate with the help of high-speed seven-wire cables that enhance the performance of the SATA.

Comparison Table Between AHCI and SATA

Parameters of ComparisonAHCISATA
VersionIt is a newer version of SATA.It is relatively older than AHCI.
ApplicationsIt specifies the actions of different host controllers like SATA.It passes the information between storage devices and host controllers.
ImplementationSince it is an advanced version of host controllers, it is not adaptable to all the operating systems.It can be easily implemented in all operating systems.
Latest versionThe latest version is 1.3.1, launched in 2011.The latest version is 3.5, launched in 2020.
CreationIt was created and launched by Intel.It was created by the Serial ATA Working Group.

What is AHCI?

AHCI stands for Advanced Host Controller Interface. It is a host controller which is designed by Intel. It was designed as an advanced version of host controllers of Serial ATA in its motherboard chips. It is directly supported indigenously in the operating system so that the users don’t have to install the driver separately. However, Microsoft Windows XP does not support this host controller and the users might have to install the drive separately. The specification of AHCI is that it specifies a structure in the system memory which is used by computer hardware makers while these makers exchange data between the connected storage devices and host system memory.

AHCI provides a standard technique to recognize, configure, and programme the adapters of SATA/AHCI to software developers and hardware designers. Although AHCI is quite different from the standard SATA 3 Gbit/s, it also enhances the capabilities of SATA’s like the queuing of native command and hot swapping which is available to the host computers. The interface has been supplanted by NVMe for current solid-state drives.

The latest version of the AHCI is 1.3.1, which was launched on November 11, 2011. If the SATA controller is not present in the AHCI mode when the operating system was installed, various operating systems which includes Windows Vista, Windows 8, Windows 10, Windows 7, and Windows 8.1, cannot arrange all by themselves to load the AHCI driver which is at boot. Even though this is a simple fix, the AHCI standard continues to have problems.

Technically, it is an implementation bug of AHCI that can be minimised and avoided, however, it has yet to be resolved. Before installing an operating system, Intel suggests converting the drive controller to AHCI or RAID as a workaround. The operating systems like Windows Vista, NetBSD (since version 4.0), Linux-based systems, macOS, GNU Mach, eComStation (since version 2.1), OpenBSD (since version 4.1), ArcaOS, FreeBSD (since version 8.0), and Solaris 10 (from version 8/07) which is provided out of the box support to AHCI.

What is SATA?

SATA stands for Serial Advanced Technology Attachment (SATA). It is a computer bus interface which is designed so that it can connect host bus adapters to various mass storage devices efficiently. These devices may be hard optical drives, hard disk drives, and or even various solid-state drives. It has overtaken the earlier Parallel Advanced Technology Attachment smoothly and has proved to be the predominant interface for storage devices.

The interface was declared in 2000 that it could provide considerable advantages over the other PATA like by reduction in costs and sizes of cable, faster transfer of data through high signaling rates, and quite efficient and effective data transfer. The Seagate Barracuda SATA V, was launched in January 2003, and was known as the world’s first SATA hard disc drive.

SATA devices and host adapters can efficiently communicate through two pairs of conductors using a high-speed serial cable. Parallel ATA (the renamed old ATA specs) employs a bit of 16 wide of data bus with various other additional support and control signals, and all of these can operate and function at a significantly lower frequency. SATA functions mainly on the same basic ATA and ATAPI command sets which are provided as traditional ATA devices and ensures compatibility in the backward with legacy ATA software and applications. A point-to-point architecture is used by SATA.

A controller’s physical connection which is to a storage device cannot be shared with any other controllers or various storage devices. Multipliers can be defined by SATA and enable an individual controller of SATA port can even drive up to 15 storage devices efficiently. In the hub, the multiplier can serve as a hub, and other controllers and storage devices are connected to the hub.

Main Differences Between AHCI and SATA

  • AHCI is a host controller interface, while SATA is an interface that connects storage devices.
  • AHCI specifies the actions of a host controller, while SATA is a host controller itself that connects storage devices.
  • AHCI supersedes the SATA, whereas SATA supersedes the PATA.
  • AHCI supports extra features like NCQ and hot-plugging, while SATA does not support such features.
  • At times, AHCI is difficult to implement in some operating systems, while SATA can be easily implemented in all operating systems.
  • Conclusion

    Hence, AHCI and SATA are two different interfaces used in operating systems. AHCI is a host controller that assigns tasks to different host controllers, while SATA connects the storage devices and host controllers.

    Though the former is more advanced than the latter, both of these interfaces provide considerable speed and perform with reputable efficiency. Both the interfaces have different features and should be evaluated.

    References

  • https://link.springer.com/chapter/10.1007/978-981-13-0599-3_9
  • https://sata-io.org/sites/default/files/images/NVMe_and_AHCI_as_SATA_Express_Interface_Options_final.pdf
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