Hello reader.

Some time ago, I've bought a new laptop, since video chip on my previous one had burnt. But despite that, I decided to fix it, and now I have two working laptops. So, to make my money for the new laptop not wasted, I want to use the old laptop somehow to my advantage.

And one little idea that came in my mind - is it possible to connect a remote (on a different computer) X server as a second, external monitor to the local one (e.g. dual-head setup)?
If it is, then how?

Thanks in advance.

Yes, it is possible.
You need to look into remote X login.

Correct me if I'm wrong, but it only allows to manually run applications on remote X server, doesn't it? What I need is to run only one desktop session (desktop environment) over two X servers, acting as two monitors.

EDIT after some "googling":
Most of info I found was about how to create setup, where several X servers act as clients to one XDMCP server in separate sessions (sorry if I'm saying smt weird, but I don't have much experience in this). My goal is to make two X servers work in one session to draw parts of one "workspace" on different computers' monitors.

You have to look also for multiple login sessions and allowing them.

Your questions aren't quite clear to me.

But you might try running a vncserver on the remote, and using vncviewer on your reconditioned laptop to connect to it. It's fun. Favourite-search-engine it.

Otherwise you might like to search on / install krfb because that is fun too. F-S-E that too.

nx is reported to be much faster, but you may not need this : http://freshmeat.net/projects/nx

The thing is that I want to use both laptops simultaneously, and use the reconditioned one as a second monitor, being an extension to the monitor of the new one. Just like anyone would connect a monitor to laptop via DVI or VGA port (using Xinerama or smt like that), I want to connect old laptop's monitor in the same manner.
VNC will only get the same image on both laptops, which is not what I need.

The only thing that came in mind that seemed something like a solution is to configure second screen device in xorg.conf, but somehow tell X server that that device is located on remote computer. If that's possible, that would probably do the trick.

You set up X to have more than one screen and you setup remote login for the other.