How to start a virtual machine 

1) In normal circumstances my virtual machine doesn't run. If I want to
   start it, it it neccessary to connect via ssh to the server
   unix.dcs.fmph.uniba.sk, i.e.
       > ssh unix.dcs.fmph.uniba.sk -l carrot
       if my name is e.g. Joseph van der Carrot. You will be asked to enter your password.  

2) If everything went fine, one problem still may appear -- virtual computer
   may refuse to start, because it is already running. In this case, it is
   recommended to verify this fact :). You can do it by jumping directly to
   step 4 of this tutorial. If the machine is not running, you can safely
   answer 'a' to unlock and start it. 

3) Virtual machine starts booting and write a lot of messages; most of them
   are not very interesting. One of the interesting messages is quite close to
   the beginning and looks roughly like this: 

Kernel command line: ubd0=/home/mrkva/ubd0.cow,/boot/ubd0.img
con0=fd:0,fd:1 con=port:44042 umid=mrkva mem=16m
ubd1=/home/mrkva/ubd1.img ubd2r=/boot/cd.iso ubd3=/home/mrkva/ubd3.img
eth0=daemon root=/dev/ubd0

   There I can find out (if I have forgotten) number 44042, which is quite
   important in next steps. This number depends on user name and doesn't
   change, so simply rememebering it should be enough. And if you are
   reading also this sentence, your machine already shows you login prompt
   on something similar to console of your machine. You DO NOT log in there! 

4) I'll try to telnet (ssh unfortunately doesn't work here) to
   unix.dcs.fmph.uniba.sk, to the port with number I was supposed to
   remember (or find out in step 3). So:
   > telnet unix.dcs.fmph.uniba.sk 44042
   and I can see login-prompt where I can safely log in and start working
   with my virtual machine. If I need more terminals, I can open another
   ones using the same telnet command.

5) If I'm logging in for the first time, there is only one user on the
   virtual machine -- root, which doesn't have any password set. It is
   STRONGLY RECOMMENDED to change it. :-)

6) After finishing I have to turn my computer correctly off (the virtual
   one, but you can also the real one, if you like:). This can be achieved
   by executing "poweroff" and waiting until it shuts down.

7) Recommendation for better security: The telnet protocol transfers
   everything in plaintext over the network. We can avoid it by using the
   following command in the step 1:
   > ssh unix.dcs.fmph.uniba.sk -l carrot -L2323:127.0.0.1:44042
   where, in place of 44042, we use our number from the step 3 (so we have
   to use the unmodified command from the step 1 for the first time to find
   it out), and then, in the step 4 we use:
   > telnet 127.0.0.1 2323
   This way, the telnet connection will be tunnelled through the encrypted
   ssh channel.