Operating systems based on Linux kernel are very stable, so the system requires the rearrangement is very rare. Various images from the LiveCD handy to satisfy curiosity, to restore the systems installed, and so on, but for myself many experienced linuksoydy prefer over the network, being able to choose only the packages you really need them. To do this, there are minimum installation images Netboot, equipped with a text intallyatorom Debian Installer. Such images do not weigh more than 20 megabytes.
Of the major changes include:
based on Linux-kernel version 3.0.3;
technology integration in GNOME 3 Ubuntu;
GDM login manager replaced LightDM;
Evolution mail client is replaced by Thunderbird;
updated Ubuntu Software Center;
window system is updated Unity.
The server version adds:
set of applications Orchestra;
service OpenStack, designed to work in large data centers;
new tools for provisioning and deployment of operating systems on different physical servers;
software to create cloud, automated OS system administration, intrusion detection, etc.
Processor: Any Intel or AMD;
Memory: 512 MB;
Sound Card: Any Sound Blaster - compatible card or built-in AC97;
Minimum free disk space: 6GB - at least, and 10GB - recommended;
Serial ATA: Most controllers supported in non-RAID mode and some in RAID-mode;
Video Card: NVIDIA, ATI, Intel ® i8xx and i9xx, SIS, Matrox, VIA;
Optical Drive: DVD-ROM.