Oracle System Architecture Question:

Database buffer contains the data which server process reads recently from disk. Database buffer may have three parts: 1. free buffer 2. dirty buffer 3. pinned buffer Free buffer area is free to be used to store data. Dirty buffer area contains the data which is updated since read from disk, but not written to the disk till now. Pinned buffer is a area where processing on specific data for current transaction is going on. Database buffer may be of three types: 1. keep 2. recycle 3. default Database buffer may be divided into five different block size buffers: 2k,4k,8k,16k,32k and 64k also but supported by most of the servers (HP, IBM AIX, SOLARIS 10)