Oracle Database Management - Oracle 10g Database Administration Concepts and Implementation Made Simple - page 233

But let me tell you one thing which we are neglecting over here
i.e. every OS has a file size limitation without going into details
e.g. in Windows 98 you cannot have file size greater than 2 GB
where as in Windows XP/Server you cannot have file size
greater than 4 GB.
So if Oracle would have said that a tablespace can reside in only
one data file than it means Oracle tablespace size is limited to the
OS maximum file size. That's the reason, Oracle has lifted this
limitation by saying that you can add as many data files as you
like. It all depends on your resource limit (e.g. Hard Disks size
etc.) but not on OS file size limit.
Bottom line is that Oracle tablespace size is unlimited and is not
bounded by OS maximum file size limit.
DROP TABLESPCE statement helps in dropping of tablespace
as shown below.
DROP TABLESPACE users;
If the tablespace is not empty then we have to add the clause
INCLUDING CONTENTS.
DROP TABLESPACE users INCLUDING CONTENTS;
Remember that if you have named the data files according to file
naming convention defined in OMF (Oracle Managed Files) then
once dropping a tablespace with DROP TABLESPACE
statement will drop/delete the data files associated with that
tablespace too otherwise you have to remove the data files
yourself at the OS level relating to that tablespace or use the
following statement which will remove the data files too.
DROP TABLESPACE users INCLUDING CONTENTS AND
DATAFILES;