unable to open '/dev/dm-1'
unable to open '/dev/sda'
unable to open '/dev/sdb'
Generating locales...
  en_US.UTF-8... done
Generation complete.
pwconv: failed to change the mode of /etc/passwd- to 0600
Using CD-ROM mount point /cdrom/
Identifying... [ddc7a595807435ac18b11d4fa8d28545-2]
Scanning disc for index files...
Found 2 package indexes, 0 source indexes, 0 translation indexes and 1 signatures
Found label 'Ubuntu 14.04 LTS _Trusty Tahr_ - Release amd64 (20140417)'
This disc is called: 
'Ubuntu 14.04 LTS _Trusty Tahr_ - Release amd64 (20140417)'
Copying package lists...gpgv: Signature made Thu Apr 17 01:35:09 2014 UTC using DSA key ID FBB75451
gpgv: Good signature from "Ubuntu CD Image Automatic Signing Key <cdimage@ubuntu.com>"

Reading Package Indexes... 0%

Reading Package Indexes... Done
Writing new source list
Source list entries for this disc are:
deb cdrom:[Ubuntu 14.04 LTS _Trusty Tahr_ - Release amd64 (20140417)]/ trusty main restricted
Repeat this process for the rest of the CDs in your set.