some questions about linux system.

Hi,i am a newbie in linux,l have some questions when i study unix system.Could you help me?thx.

Q1:an linux file system is broken,it can not be mounted after system boot up .how to recover it?

Q2:When the UNIX system shore memory is not enough,how to change the system paramenters?

Q3:How creat a raw device(disk) on linux machine? How to craet files system on it and then mount it?

This sounds very homework like so I will not answer the questions. Read the forum rules. If you can be more specific about your questions, perhaps give an example of which filesystem is broken, what you want to use the raw devices for, and which parameters you want to change - then I would be more willing to answer you.

thanks,my friend.