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Only 'sdb' shows up when installing 12.04 on a new Dell inspiron 14z

I tried to install ubuntu 12.04LTS on my Dell 14z inspiron 5423 i already try with Live way but i can't make it install on right partition ps. it show only SSD .So i try alternative way by install via wubi and it install complete but when i reboot it show message that"No root file system is defined. Please correct from the partition menu" firstly that drive is NTFS then i find some advice that it should be ext2,3,4 but when i change it format it doesn't show on wubi anymore anybody have a suggestion?? ps.sorry for my poor english


1 Answer 1


It seems Ubuntu sees the small SSD and big HDD set in RAID and cannot install Ubuntu side by side without disabling the RAID. See Only 'sdb' shows up when installing 12.04 on a new Dell inspiron 14z.

I am not sure why WUBI install didn't work at first. Changing the NTFS partition to ext4 was a mistake. WUBI install does not use the partition directly but uses a large file inside a Windows partition (NTFS). This is why one can use WUBI install without making any new partition. The installation will put the big file in C: by default. Since Windows cannot read/write ext4 (or any other Linux partition) WUBI cannot use these types of partitions. Remember WUBI installations is done from within Windows.


First, Boot Windows and uninstall WUBI installation using Windows Uninstall feature.

  1. Boot from USB stick and select "Try Ubuntu"
  2. Open a terminal by pressing Ctrl+Alt+T and enter sudo dmraid -E -r /dev/sda.
  3. Using Gparted delete the ext4 partition you had created before. Default side-by-side Ubuntu install should create all the partitions it needs on its own.
  4. Start the Install Ubuntu process as before.

Once the RAID is removed you should get the "alongside" option. However, you may choose "something else" and use the small SSD for the / partition and the the HDD for /home and swap. See Is it safe to install the / partition on an SSD?

  • I cann't create a new logical par via Gpart i can only create a primary part and when i try to create another part it said that my primary part is more than 4 already so what should i do?
    – user93887
    Commented Oct 3, 2012 at 17:26
  • Do not create a 4th primary partition. Create an Extended partition. Inside the extended partition you will be able to create as many logical partitions as you need/want.
    – user68186
    Commented Oct 3, 2012 at 17:49

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