I'm not sure what is wrong here but when running fdisk -l I don't get an output, and when running     fdisk /dev/sdb # I get thisfdisk: unable to open /dev/sdb: No such file or directoryI'm running Ubuntu 12.10 ServerCan someone please tell me what I'm doing wrong? I want to delete /dev/sdb2-3 and just have one partition for sdbThe only thing I've done differently with the setup of this server is use ext4 instead of ext3, I figured the extra speed of ext4 would help since I am using SSDs nowroot@sb8:~# ll /dev/sd*brw-rw---- 1 root disk 8,  1 Nov 23 14:58 /dev/sda1brw-rw---- 1 root disk 8,  2 Nov 23 14:55 /dev/sda2brw-rw---- 1 root disk 8, 17 Nov 23 19:20 /dev/sdb1brw-rw---- 1 root disk 8, 18 Nov 23 15:45 /dev/sdb2brw-rw---- 1 root disk 8, 19 Nov 23 14:51 /dev/sdb3brw-rw---- 1 root disk 8, 33 Nov 23 15:47 /dev/sdc1brw-rw---- 1 root disk 8, 49 Nov 23 15:48 /dev/sdd1root@sb8:~# cat /proc/partitionsmajor minor  #blocks  name   8        0  117220824 sda   8        1  112096256 sda1   8        2    5119968 sda2   8       16  117220824 sdb   8       17   20971520 sdb1   8       18   95718400 sdb2   8       19     526304 sdb3   8       48 1953514584 sdd   8       49 1863013655 sdd1   8       32 1953514584 sdc   8       33 1863013655 sdc1root@sb8:~# ll /dev/disk/by-path/total 8drwxr-xr-x 2 root root 4096 Nov 23 15:48 ./drwxr-xr-x 5 root root 4096 Nov 23 15:42 ../lrwxrwxrwx 1 root root   10 Nov 23 14:58 pci-0000:00:1f.2-scsi-0:0:0:0-part1 -> ../../sda1lrwxrwxrwx 1 root root   10 Nov 23 19:20 pci-0000:00:1f.2-scsi-1:0:0:0-part1 -> ../../sdb1lrwxrwxrwx 1 root root   10 Nov 23 15:45 pci-0000:00:1f.2-scsi-1:0:0:0-part2 -> ../../sdb2lrwxrwxrwx 1 root root   10 Nov 23 15:47 pci-0000:00:1f.2-scsi-2:0:0:0-part1 -> ../../sdc1lrwxrwxrwx 1 root root   10 Nov 23 15:48 pci-0000:00:1f.2-scsi-3:0:0:0-part1 -> ../../sdd1root@sb8:~# df -T /devFilesystem     Type 1K-blocks    Used Available Use% Mounted on/dev/root      ext4 111986032 1993108 104388112   2% /
/dev/sdb: No such file or directory (but /dev/sdb1 etc. exist)
linux;ubuntu;devices;disk
On most non-embedded Linux installations, and many embedded installations, /dev is on a RAM-backed filesystem, not on the root partition. Most current installations have /dev as a tmpfs filesystem, with the udev daemon creating entries when notified by the kernel that some hardware is available. Recent kernel offer the possibility of having /dev mounted as the devtmpfs filesystem, which is directly populated by the kernel.I think Ubuntu 12.10 still uses udev. Either way, /dev should not be on the root partition (as shown by the output of df /dev), it should be on its own filesystem. Did you accidentally unmount /dev?The first thing you should try is to reboot: this should mount /dev properly. Before that, check that you haven't added an entry for /dev in /etc/fstab (there should be no line with /dev in the second column).Even with /dev on the root partition, you can create /dev/sdb by runningcd /devsudo MAKEDEV sdbBut not having /dev managed dynamically isn't a stable configuration, you'll run into similar problems for a lot of other hardware.