fb53硬盘问题，求助

freepower

freebsd5.3r下，dmesg显示：

ad0: 19536MB <ST320423A/3.02> [39693/16/63] at ata0-master UDMA66
ata1-master: FAILURE - ATA_IDENTIFY status=7f<READY,DMA_READY,DSC,DRQ,CORRECTABLE,INDEX,ERROR> error=7f<UNCORRECTABLE,MEDIA_CHANGED,NID_NOT_FOUND,MEDIA_CHANGE_REQEST,ABORTED,NO_MEDIA,ILLEGAL_LENGTH> LBA=0
ata1-master: FAILURE - ATA_IDENTIFY status=7f<READY,DMA_READY,DSC,DRQ,CORRECTABLE,INDEX,ERROR> error=7f<UNCORRECTABLE,MEDIA_CHANGED,NID_NOT_FOUND,MEDIA_CHANGE_REQEST,ABORTED,NO_MEDIA,ILLEGAL_LENGTH> LBA=0
ata1-master: FAILURE - ATA_IDENTIFY timed out
ata1-master: FAILURE - ATA_IDENTIFY timed out

在freebsd4.x下没有这种错误提示

请问是什么原因造成的 ？？