我在装gentoo的时候当时就疑惑过为什么我的硬盘被recognize as /dev/hda，以前都是/dev/sda的。。。
今天发现是因为内核里面没有编译SATA的支持。
打开对SATA的支持，关掉对ATA的支持。（注意选上你相应的设备支持，像我是Intel ICH）
记得backup kernel...否则万一出错了就不好完了。。。
p.s. performance comparison
freepeter@localhost ~ $ sudo hdparm -tT /dev/hda
/dev/hda:
Timing cached reads: 1392 MB in 2.00 seconds = 695.92 MB/sec
Timing buffered disk reads: 8 MB in 3.54 seconds = 2.26 MB/sec
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freepeter@localhost ~ $ sudo hdparm -tT /dev/sda
/dev/sda:
Timing cached reads: 1706 MB in 2.00 seconds = 852.66 MB/sec
Timing buffered disk reads: 94 MB in 3.04 seconds = 30.93 MB/sec
另外UDMA也打开了。。。生活真美好～～～
p.s.
/dev/sdX device files are for SCSI, SATA disks.
/dev/hdX device files are for IDE hard disks.