User`s guide

Basic Structures
2-2 Oracle Database Installation and Administration Guide
Therefore, Oracle Database 11g Release 2 for BS2000/OSD requires the POSIX file
system. While in Oracle Database 10g the use of the POSIX file system was optional, it
is mandatory in Oracle Database 11g Release 2.
During the installation of the Oracle Database software executables, libraries and other
files are installed both in the BS2000 DMS and in the POSIX file system.
You must provide access to the POSIX file system. Refer to Chapter 3, "Oracle
Database Installation and Deinstallation" for information about access to the POSIX
file system.
2.1.2 POSIX Shell
Starting with Oracle Database 11g Release 2, you can start a subset of Oracle Database
utilities not only in the BS2000 environment by using SDF commands, but also in the
POSIX shell by using shell commands.
The diagnostic data in ADR can be viewed with the command line utility ADRCI . Start
this utility in the POSIX shell.
Set the environment variable ORACLE_HOME , prior to starting utilities in the POSIX shell.
2.1.3 Processes
All processes of an Oracle Database instance, for example, dedicated server processes
and background processes, run as BS2000 tasks.
If you start a client utility, such as SQL*Plus, in the BS2000 environment by using SDF
commands, then the corresponding program is executed in the BS2000 login task.
If you start a client utility in the POSIX shell, then a new POSIX process is created.
Client processes running in the POSIX shell connect to an instance, such as clients in
the BS2000 environment. The server process always starts in the BS2000 environment.
For more information about processes in the BS2000 environment, refer to
Chapter 9,
"Oracle Net Services".
2.2 Basic Structures
The concepts of tasks (that is, processes in Oracle terminology) and memory structures
(areas) are not BS2000 specific.
Refer to "Memory Architecture" in Oracle Database Concepts and "Process Architecture"
in Oracle Database Concepts for detailed information.
This section includes the following:
■ Database Files and Log Files
■ Other Oracle Database Files
■ Oracle-Managed Files
■ Bigfile Tablespaces
2.2.1 Database Files and Log Files
One or more database files contain the data dictionary, the user data, and indexes.
Oracle Database requires a minimum of two log files that need not be the same size,
although on BS2000/OSD, the recommended minimum is 10000 PAM blocks. The size
of a log file is set in BS2000 blocks and not Oracle Database blocks.