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

I got my brand new Dell Inspiron 14z yesterday, but failed to install Ubuntu.

I can boot from a USB stick, and it works well. When trying to install, I confirm that the laptop is connected to the Internet etc (as in the 2nd picture in the installation guide: How do I install Ubuntu?). When pressing "Continue" I do not get the question on installation type (alongside/replace/something else). Instead I get a window where I can select partitions:

The problem is that I can only select sdb in the drop drop down box, and I can do do nothing with sdb (like adding partitions etc).

The main disk (sda) is partitioned using GParted the following way:

As far as I understand from other posts on Ask Ubuntu, this should work.

What can I do to install Ubuntu alongside with Windows 7?

It seems you have a small SSD (/dev/sdb) and a hard drive (/dev/sda) that uses Intel Smart Response Technology, that Ubuntu recognizes as RAID0.

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 extended partition /dev/sda4 and all the logical partions inside it (sda5, sda6, sda7).


4. Start the Install Ubuntu process as before.

(The above worked)

Alternately

If you have the Intel Smart Response Technology:

1. Deactivate it from within Windows using the GUI,


2. Change the SATA mode in the BIOS from RAID to normal.

Then your Ubuntu installer should recognize both disks. (But beware, I don't know how Windows or rather ntfs behaves if you deactivate the RAID mode. Your ntfs filesystem could also get damaged) From No HDD shows up during install 12.04 on Lenovo U410.

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?

Hope this helps