2012年2月16日星期四
ATA & AHCI
ATA技术是一个关于IDE（Integrated Device Electronics）的技术规范。IDE接口全球标准化协议将该接口自诞生以来使用的技术规范归纳成为全球硬盘标准，这样就产生了ATA（Advanced Technology Attachment）。你可以把它理解成ATA接口硬盘的一种工作模式。
而AHCI（Advanced Host Controller Interface）是SATA主机总线接口的一种工作模式。AHCI是在Intel的指导下，由多家公司联合研发的接口标准。它的主要作用是在系统内存和串行ATA设备之间扮演一种接口的角色。将硬盘模式设置成这个会提高硬盘运行速度，而AHCI技术需要硬盘和主板两方面的支持。对于硬盘而言，目前还没有完全支持AHCI 1.0的产品，但部分硬盘已经支持NCQ功能，配合支持AHCI的主板就可以实现。 AHCI gives software developers and hardware designers a standard method for detecting, configuring, and programming SATA/AHCI adapters. AHCI is separate from the SATA 3Gb/s standard, although it exposes SATA's advanced capabilities (such as hot swapping and native command queuing) such that host systems can utilize them. As of October 2010, the current version of the specification is v. 1.3.
AHCI操作系统支持：
AHCI is supported out of the box on Windows Vista and newer versions of Windows, Linux-based operating systems (from kernel 2.6.19 onwards), OpenBSD (version 4.1 onwards), NetBSD, FreeBSD, OS X, and Solaris 10 (8/07 and onwards). DragonFlyBSD based its AHCI implementation on OpenBSD's and added extended features such as port multiplier support. Older versions of operating systems require hardware-specific drivers in order to support AHCI. Windows XP does not provide support out of the box.
Some operating systems, notably Windows Vista and Windows 7, do not configure themselves to load the AHCI driver upon boot if the drive controller was not in AHCI mode at the time of installation. This can cause failure to boot with an error message if the SATA controller is later switched to AHCI mode. For this reason, Intel recommends changing the drive controller to AHCI or RAID before installing an operating system.只有安装windows vista或windows 7时设置为AHCI，该模式才会启用，如果操作系统安装之后才切换到AHCI模式，将导致操作系统启动失败，所以intel建议在安装操作系统之前设置AHCI模式。AHCI 为 SATA 设备提供了若干种功能。其中包括热插拔功能和电源管理功能。
这就是ATA 和AHCI 的区别，ATA模式下的硬盘没有AHCI模式下的硬盘运行速度快，因为只有SATA接口的硬盘可以设为AHCI，而ATA模式是针对IDE硬盘存在的，这两种不同接口在传送数据快慢上有很大区别。
// 发贴者：放牛娃的春天 @ 二月 16, 2012 
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