what is ssd5/6/7 in "iostat -en"

Hi

what is ssd5 here in output.

it is showing in iostat -en/En ,but not in format command.

and it not is use also.

it is 480R system with 2 disk and cd-rom .

root@rcomsapp40a05 # iostat -en

  ---- errors ---

  s/w h/w trn tot device

    0   0 283 283 c0t0d0

   0  15 11814 11829 ssd5

    0   1   0   1 c1t1d0

    0   0   0   0 c1t0d0

    0   0   0   0 10.8.55.84:/Interface/dss

    0   0   0   0 10.8.55.84:/Interface/phonegen

    0   0   0   0 10.8.55.84:/Interface/asg

    0   0   0   0 10.8.55.84:/Interface/statp40

    0   0   0   0 97.253.16.100:/bdcusers/pmdata

    0   0   0   0 97.253.16.100:/infocomm/mm

    0   0   0   0 97.253.16.100:/sapmnt/trans

    0   0   0   0 97.253.16.100:/sapmnt/P40/profile

    0   0   0   0 97.253.16.100:/sapmnt/P40/global

    0   0   0   0 97.253.16.100:/sapmnt/WMS_IN

    0   0   0   0 97.253.16.100:/sapmnt/WMS_OUT

    0   0   0   0 97.253.16.100:/sapmnt/WMS_Bckup

    0   0   0   0 97.253.16.100:/sapmnt/AMC/

    0   0   0   0 97.253.16.100:/sapmnt/AMC_BACKUP

    0   0   0   0 97.253.16.100:/sapmnt/MASTER

    0   0   0   0 97.253.16.100:/sapmnt/epayserver

    0   0   0   0 97.253.16.67:/tmp

    0   0   0   0 97.253.16.100:/sapmnt/P40/exe