Hi All, I have always been thinking of this, but could'nt find answer. In AS400 Hardware manuals when we check the DASD Part number against feature codes we find that a single feature code is having multiple part numbers along with description mentioning LEVEL's . What is meaning of this level? What will be the result if I add two DASD belonging to two different level in the ASP(auxilary storage pool)or Disk Parity or Disk mirroring ? TAI. RGDS Rajesh