Hi, all I have a question, just for curious. I can prove "alter system dump datafile # block #" will *NOT* read the block into buffer cache although that block is not in the buffer cache. But, can anyone prove if that block is dirty, will DUMP action cause the DBWn to write this block into disk or not? -- Kamus <kamusis@xxxxxxxxx> Oracle8i & 9i Certified DBA from China