Difference between PFILE and SPFILE

Q#1 Difference between PFILE and SPFILE?

PFILE:

• PFILE is a parameter file.
• PFILE is a init.ora file.
• PFILE is a static parameter file.
• PFILE is a text file.
• PFILE can be modified with an operating system editor.
• Changes to the file take effort on the next startup.
• Only opened during instance startup.

Its default location is:$ORACLE-HOME/dbs.
Types of Parameter:
There are two types of parameter
Explicit:
Having an entry in the file.
Implicit:
No entry within the file: but assuming the Oracle default values.

SPFILE:

• SPFILE is a server parameter file.
• SPFILE is a dynamic parameter file.
• SPFILE is a binary file.
• SPFILE are maintained by Oracle server.
• Always resides on the server side.
• Ability to make changes persistent across shut down and startup.
• Can self-tune parameter file?
• Can have Recovery Manager support backing up to the initialization parameter file.