bash-3.00# cat /proc/partitions
major minor  #blocks  name

   3     0   78150744 hda
   3     1      96358 hda1
   3     2    2000092 hda2
   3     3   10000462 hda3
   3     4   66051247 hda4
   8     0  293057352 sda
   8     1     152586 sda1
   8     2    2096482 sda2
   8     3   52428127 sda3
   8     4  238372470 sda4

bash-3.00# mount /dev/sda3 /mnt/sda3/
mount: special device /dev/sda3 does not exist

bash-3.00# fdisk /dev/sda

Unable to open /dev/sda

bash-3.00# dmesg | grep -i sda
SCSI device sda: 586114704 512-byte hdwr sectors (300091 MB)
sda: Write Protect is off
sda: Mode Sense: 00 3a 00 00
SCSI device sda: drive cache: write back
SCSI device sda: 586114704 512-byte hdwr sectors (300091 MB)
sda: Write Protect is off
sda: Mode Sense: 00 3a 00 00
SCSI device sda: drive cache: write back
 sda: sda1 sda2 sda3 sda4
sd 0:0:0:0: Attached scsi disk sda