Problem with Metasploit Ruby Language

[centaurios]

I am not really familiar with ruby programming language neither a professional in metasploit, I really need to understand how this exploit ms01_033_idq.rb works.
what I don't get is target.ret[-4, 4] and rand_text_alphanumeric(1). I wonder if you could help me figure out what these commands are and what they actually do.

Thanks in advance

[espreto]

Here not is support for metasploit.

For more information, see.

Metasploit Unleashed - Mastering the Framework

And join the irc channel.

#metasploit

Regards,