[drive:] Change the current driver, without changing its current directory
cd [drive:] [path] Just change the current directory of driver, without changing the current driver.
cd [/d] [drive:] [path] Change the current driver and its current directory
cd [\] Come back to root of the current driver
cd [..] Up one level
If you are in the current driver and want to enter its directory, you could use relative path.
e.g., The current driver is E: E:\>，so you can just type 'cd \joan\joansky' to enter 'E:\joan\joansky>'
If the directory you want to enter is not in the current driver, you need to use absolute path 'cd e:\joan\joansky'