Concepts and Architecture Question:

The Physical Architectureof the Oracle involves,
1)SGA i.e Shared Global Area or System Global Area part of the Memory of system which is used by the Oracle Database.

2)Background Processes: To start up the oracle data base these are the minimum background processes required.

a)PMON: Process Monitor releases all the reources and transactions(I/D/U) which is held by the user after disconnecting from the database.

b)SMON: System Monitor performs the failure of Instance Crash suppose if the Data missing in DF. SMON recognizes such inconvinence and writes the data from RF to DF

c)Checkpoint: All the DB buffer changes wil be written into the DF aftr issuing the checkpoint. Checkpoint will be issued on timely basis by DBA.

d)DBWR: It writes the DB buffer changes to DF aftr the check point.

e)LGWR: It writes the LOGBUFFER changes to the RF when rollback or checkpoint is encountered.

3)Database files: Oracle data base contains three types of files that are,
a)DataFile(DF)
b)Redolog Files(RF)
c)Control File(CF)

To start up DB one Datafile two Redologfile and one Control file is needed.

Datafile is the place where data gets stored permanentely.
Redolog file is the place where all the comitted data gets stores.
Control file stores the information about the DF & RF.

Oracle Architecture also comprises of the following,
1)Tablespace
2)Extents
3)Segments
4)Data Base Blocks