PeopleSoft Architecture Quick Walkthrough

File server:
File server is the home for the peopletools executables and Peoplesoft application.About Peopletools, it's a collection of binary files, executables and configuration files.For any Peoplesoft application to work, primarily the tools should be installed. Peoplesoft applications such as HRMS, Finance are installed above this base directory. Fileserver is allways on windows.
File system structure:
Choose a Peoplesoft home directory while installing peopletools

1. For e.g, C:\XXXXDEMO – Peoplesoft home (generally known as PS_HOME)
   
2. Specify Unicode or non-unicode installation
   
3. Specify the bin path of the database to connect
   
4. Install the Peoplesoft application with the necessary modules after the tools installation is complete
   

Webserver: Webserver can be either Weblogic or Websphere. In this context let us look in to weblogic as a component.
Points to be noted:

1. More than one domain can be hosted on a Webserver. In other words, more than one instance can run on a single Webserver simultaneously.
   
2. Weblogic is installed on a server and you specify the Bea home location.
   
3. For e.g. C:\BEA - Weblogic Home
   

The domains D1, D2, D3 reside in the path ….(Till PeopleTools 8.44)C:\BEA\wlserver6.1\config\D1\C:\BEA\wlserver6.1\config\D2\C:\BEA\wlserver6.1\config\D3\. Startiing from Peopletools 8.46 domain are created under PSHOME/webserve Directory.

Application Server:

1. This component acts as the workhorse at the center of the environment.
   
2. Collection of processes such as psappsrv, psqrysrv, pssamsrv, etc comprises an application server.
   
3. Invoking these appserver processes requires a Peoplesoft home.
   
4. There can be more than one domain for an appserver.
   
5. $PS_HOME/appserv is the default path of an appserver where $PS_HOME denotes the Peoplesoft home.
   
6. The domains are configured under the directory $PS_HOME/appserv
   
7. The configuration files pertaining to the domain are under the path $PS_HOME/appserv/<domainname>
   

There are two major components that make up a PeopleSoft application server.The foundation upon which the application server is built is BEA Tuxedo. Tuxedo manages connections to the application server, spawns and decays internal processes to scale appropriately depending on workload, and allows a platform independent communication layer between the client and PeopleSoft server processes.

Jolt is a Java-enabled subset of Tuxedo. It performs identical functions, but handles connections to Java applets/servlet exclusively. All communications between the application server and the web server are managed through Jolt.

Application server when started, invokes more than a dozen number of appserver processes. The server processes take their orders from Tuxedo, communicate with the database with SQL, and pass responses (if required) back up the line to Tuxedo or Jolt, depending on where the request came from.
Tuxedo can be considered as a separate component.For e.g. Tuxedo is installed under c:\TUXEDO directory.
All the executables and configuration files lie under this TUXDIR home directory... (In Peopletools 8.45 and above the tuxedo is installed under c:\bea\Tuxedo8.1)The screen shot below explains it. Batch server / Process scheduler server:
Matched very closely to the database server is the batch server. The batch server holds a number of pre-programmed processes and tools that allow it to perform common functions against a database without the need for user intervention.
$PS_HOME/appserv/prcs Default path where the process scheduler domain resides.

$PS_HOME/appserv/prcs/XXXXDEVL XXXXDEVL is the domain name.
$PS_HOME/appserv/prcs/XXXXDEVL/cache Cache details
$PS_HOME/appserv/prcs/XXXXDEVL/logs Log files
$PS_HOME/appserv/prcs/XXXXDEVL/log_output File output after the process is completed
This component acts as the report scheduler of the environment.

1. Collection of processes such as psaesrv, psdstrv, etc comprises a batch server or a process scheduler.
   
2. Invoking these processes requires a Peoplesoft home.
   
3. There can be more than one domain for a process scheduler.
   
4. $PS_HOME/appserv/prcs is the default path of a process scheduler where $PS_HOME denotes the Peoplesoft home.
   
5. The domains are configured under the directory $PS_HOME/appserv/prcs
   
6. The configuration files pertaining to the domain are under the path $PS_HOME/appserv/prcs/<domainname>
   

Database server:
This component can be further split up into three different categories Database Tables
When referring to the tables in a PeopleSoft database, we always categorize them into three general areas:
System Catalog Tables
System catalog tables are analogous to a table of contents for a book, or to File Allocation Tables on a hard drive. The structure and table names vary depending on which RDBMS is being used, but the function is identical. The system catalog tables keep track of all of the objects that reside in the database instance.A term often used to describe the contents of the system catalog tables is metadata. This term means data about data.
Peopletools Tables
While the system catalog tables contain metadata about all objects in the database, the Peopletools tables hold metadata about the PeopleSoft application that is installed on the database. The Peopletools tables contain the structure that applications use to define specific objects. The structure of the tables is the same for all applications. Each application enters data into the Peopletools tables when it is installed.To take one example, the table PSMENUDEFN contains columns that are used to define the navigation for an application. The columns in the table include the menu name, label, menu group it belongs to, a version number, and other property information.The Peopletools tables define the structure of all objects that make up an application. The contents of the tables are filled in by the specific application installed. Obviously, navigation will vary between a Human Resources application and a Student Administration application.The naming convention used for Peopletools tables is PS*.
Application Data Tables
As you would expect, the Application Data tables contain data entered for use by your organization. The specific tables and their structure are determined by the application installed. You enter the data. Any table updated as part of a component is an application data table.For example, an ERP application will include tables to store inventory information, while a Human Resources application will offer tables to hold employee data. PeopleSoft supplies databases that include sample data for use in development and testing, but during implementation, you will start with empty tables, and fill them with your own rows of data.The naming convention used for Application Data tables is PS_*.
Metadata-Driven Architecture
From the very beginning, PeopleSoft has used metadata to drive the delivery of its applications. All of the objects that make up an application are stored in the Peopletools tables rather than externally in code. The processes written in code are used to fetch the object data from the Peopletools tables, compile it, and deliver the results to the user interface.