Oracle Database Discussions

Well, I am trying to install Oracle 11g Database (Personal Edition) and, as I try to key in an administrator password, I get error INS-30004, whilst I am trying to key in a password with the following format, amongst others, which have proven to be invalid: Anaa$aaaa (9 characters long).
A refers to A-Z
a refers to a-z
$ is the literal $ sign

I have also tried using numbers within other passwords, since I tend to keep passwords based on similar phrases which I memorize. Has anyone else encountered this problem? Why is security so restrictive by default? Can't a superuser override this? I do not really bother about password complexity for training environments, since the philosophy is to make the environment as simple as possible, which is different from the production environment, where, best practices are taken into consideration.

I also noticed that Oracle does not seem to enjoy running in environments having less than 2Gb of RAM, and, this might be a problem on my little laptop, is there a way of installing a 'mini-version' for tutorials and training?

So far I had installation issues when trying to install Ora11g within the following environments:
Windows Server 2008 running as a guest machine on VMWare due to memory available. I guess Windows is memory hungry.
Ubuntu Server, because I could not find a way of installing x-server, so I could not install oracle from a UI. Can oracle be installed through apt-get commands, or similar installation packages? I used to run CentOS as well on another VM, hoping to find a solution for these issues; and I have training deadlines as well.

What happened to Oracle 12g, is it still in beta stage?