oracle 11.2.0.1.0 oradiag_oracle $HOME

From what I read so far this directory and sub directories get created everytime a user connects to Oracle. I have a few more questions:

1) Is there any other reason why this directory is needed?

2) is there anyway to re-direct the directory to a different location other than $HOME? is so how?

3) is there any way to disable the creation of this directory, is so how?

4) If it can't be disabled, I can write a script to remove information under that directory, but can somebody tell me what is safe to remove?

Thanks in advance to all those who answer this post.

BTW, I am running on AIX 6.1 box if this information is pertinent to the issue.