On Tuesday 16 April 2002 09:14 pm, bob smith wrote:
> I was looking around the gentoo site and saw an
> interesting link about "User Mode Linux". I checked
> the website and it looks really cool. It allows
> you to have Linux running within Linux. I assume that
> it is something like VMWare. I immidiately thought of
> the posting about the Linux store and how to restrict
> users from doing harm to the system. It looks like
> this is a possible solution to that problem. Has
> anyone had any experience with UML? I would like to
> use it to try and get XFree86 working with the
> ati-gatos drivers (I hosed my system the last time I
> tried it).

Yes, I was working with it a bit just a few weeks ago.  I wanted to setup a 
virtual server that handled my web, smtp, and eventually file serving in a 
"portable" way.  That is, I wanted to be able to shut it down, copy over 
the disk files to another computer and start it up with minimal 
interruption (a few minutes maximum).

I looked at UML and VMWare.  UML looks pretty slick.  It's fast and seems to 
take up less memory normally than VMWare.  However, it wasn't horribly 
reliable when I did my testing.  There was constant disk thrashing and I 
found myself running out of memory the longer I used it.  Once, it even 
locked up my system so badly that I needed a hard reboot.  It was after 
this that I went with VMWare which, while bloated, has never given me 
problems.

Through questions on the uml support lists and watching replies to other 
people, I came to the conclusion that my problems would likely have gone 
away if I had just use a tmpfs based /tmp directory on my host system.  I 
haven't really had time to check if that's true.. but I have no reason to 
doubt it.

I never tried to get X working (it's just a server, after all).  I would 
*strongly* suggest you read about how it's done on their website.  It's 
entirely possible that it doesn't use X drivers at all.  Off the top of my 
head, I think it's just an Xnest using whatever X your host system is 
running.

UML is a blast to play around with if you're a geek, though.  I strongly 
recommend it to anybody who thinks building systems from scratch is a fun 
time :-)
-- 
Kurt Granroth - "KDE -- Conquer Your Desktop"
KDE Developer/Evangelist | granroth@kde.org
http://www.granroth.org  | kurt@granroth.org