How FreeBSD identifies hard disks and drives

FreeBSD identifies various types of hard disks and drives with following naming convention

ad ATAPI (IDE) disk

da SCSI direct access disk

acd ATAPI (IDE) CDROM

cd SCSI CDROM

fd Floppy disk

To know the hardware detected by the kernel at boot time refer the file /var/run/dmesg.boot or use the command dmesg. The various hard disks and drives detected by the FreeBSD kernel can be determined with the help of either of the following commands

dmesg | egrep ‘^ad[0-9]|^da[0-9]’

(or)

egrep ‘^ad[0-9]|^da[0-9]’ /var/run/dmesg.boot

Eg1: $ egrep ‘^ad[0-9]|^da[0-9]’ /var/run/dmesg.boot

ad0: 476940MB <WDC WD5000AADS-00L4B1 05.04C05> at ata0-master SATA300

ad0: 976773168 sectors [969021C/16H/63S] 16 sectors/interrupt 1 depth queue

da0 at umass-sim0 bus 0 target 0 lun 0

da0: <Imation Atom PMAP> Removable Direct Access SCSI-0 device

da0: Serial Number \^_

da0: 40.000MB/s transfers

da0: 3820MB (7823360 512 byte sectors: 255H 63S/T 486C)

ad0: Intel check1 failed

ad0: Adaptec check1 failed

ad0: LSI (v3) check1 failed

ad0: LSI (v2) check1 failed

ad0: FreeBSD check1 failed

To determine the info about ATA disks, there exists a command utility atacontrol.

Eg 2: atacontrol list

ATA channel 0:

Master:  ad0 <WDC WD5000AADS-00L4B1/05.04C05> Serial ATA II

Slave:       no device present

ATA channel 1:

Master:      no device present

Slave:       no device present

ATA channel 2:

Master:      no device present

Slave:       no device present

ATA channel 3:

Master:      no device present

Slave:       no device present

Eg3: atacontrol info ata0

Master:  ad0 <WDC WD5000AADS-00L4B1/05.04C05> Serial ATA II

Slave:       no device present