ODM I/O normally bypasses the file system cache and directly reads from and writes to disk. Cached ODM enables some I/O to use caching and read ahead, which can improve ODM I/O performance for certain workloads. Cached ODM can perform a conditional form of caching that is based on per-I/O hints from Oracle. The hints indicate what Oracle will do with the data. ODM uses these hints to perform caching and read ahead for some reads, but ODM avoids caching other reads, even for the same file.