• demodb contains the database data;
• demodb_lgar000, 001 and so forth are log archives used for point in time restore or in the event of a system crash;
• demodb_lgar_t - represents the temporary log archive file;
• demodb_lgat - represents the active log and holds the recent changes to the database;
• demodb_t32766 represents a temporary volume; (Note: You might see other value than t32766 appended to the database name as the value decreases from 32766 to 1)
• demodb_lgat__lock - displays which process holds the lock on the database;
• demodb_loginf - holds log archive information;
• demodb_vinf - holds volume creation information;
• lob folder is where CLOB/BLOB data types are stored;

牛人看的,一般人大概看下就可以了. 以demodb为例.