16. Identify all R3 Basis configurations.
A: Central system with centrally installed presentation software.
B: Two-level client/server system with rolled-out presentation software.
C: Two-level client/server system. Presentation and application run on the same computer.
D: Three-level client/server system. Presentation, application and database run on
separate computers.
17. What is the maximum number of session per user session?
Six.
18. What are the Roll and Page areas?
The Roll and Page areas are SAP R/3 buffers used to store user contexts ( process requests ). The SAP Dispatcher assigns process requests to work processes as they are received. If the required work process is unavailable the process requests are queued in the Roll and Page Areas.
19. The CPI-C Starter Set consists of what calls? * not covered in manual
The calls are embedded in ABAP/4 or C. The library is CPICSDK, RFCSDK, SAPMNT/TEK/EXE.
CMINIT Initialize_Conversation Define communications parameters.
CMALLC Allocate_Conversation Establish conversation.
CMACCP Accept _Conversation Accept conversation
CMSEND Send Send data
CMRCV Receive Receive Data
CMDEAL Deallocate_Conversation Terminate conversation
20. What is ABAP/4-Query? * not covered in manual
Used for generating ABAP/4 reports not contained in R/3 standard; it is especially intended for users who have no programming knowledge of ABAP/4. Description of the requested result of a report written in ABAP/4. It is a link into logical databases.
Monday, November 24, 2008
System Architecture - Interview Questions
11. Identify the two update types and explain their differences.
If an online work process updates the database directly the update will be synchronous, or immediate. If on the other hand the online work process uses an update work process the update type will be asynchronous, which has log records.
12. What has log records?
Asynchronous updating. Online programs generate log records which are then handled by an update work process after the online portion is complete.
13. What are the types of log records?
Primary U1, critical timing and must complete successfully for continuation. If an error occurs, processing ends and a rollback occurs.
Secondary U2, several may line up after a U1, if an error occurs, that block stops,
rolls back and processing continues.
14. What does a service refer to within R3?
A service is a process or group of processes that perform a specific system function ( i.e. “service” ) and often provide an application programming interface (API) for other processes to call.
15. What does it mean that R3 is a multi-client system?
Highly suited to the multi-level client/server architectures, for example, the three level concept for the presentation, application logic and data storage.
If an online work process updates the database directly the update will be synchronous, or immediate. If on the other hand the online work process uses an update work process the update type will be asynchronous, which has log records.
12. What has log records?
Asynchronous updating. Online programs generate log records which are then handled by an update work process after the online portion is complete.
13. What are the types of log records?
Primary U1, critical timing and must complete successfully for continuation. If an error occurs, processing ends and a rollback occurs.
Secondary U2, several may line up after a U1, if an error occurs, that block stops,
rolls back and processing continues.
14. What does a service refer to within R3?
A service is a process or group of processes that perform a specific system function ( i.e. “service” ) and often provide an application programming interface (API) for other processes to call.
15. What does it mean that R3 is a multi-client system?
Highly suited to the multi-level client/server architectures, for example, the three level concept for the presentation, application logic and data storage.
R/3’s system architecture Interview Questions
1. What is the function of the SAP Dispatcher?
The SAP Dispatcher is the proprietary control agent which, along with the respective operating system, manages the resources for the R/3 applications.
The main tasks of the dispatcher are:
1) Equal distribution of transaction load to the work processes.
2) Management of buffer areas in main memory.
3) Integration of the presentation level.
4) Organization of communication activities.
2. What is a Work Process and identify the ones within R3.
A work process is where individual dialog steps are actually processed and the work is done. Each work process handles one type of request:
online, (process only one request at a time),
background, (started at a specified time),
update, (primary, U1, or secondary U2),
enqueue, (lock mechanism)
spool, (generated online or during background processing for printing).
3. In R3 there are 2 services that deal with communication. Identify and explain their function.
1) Message service: used by the application servers to exchange short internal messages, all systems communication.
2) Gateway service: enables communications between R/3, R/2 and external applications, using the CPI-C protocol. Also used by EDI, RFC, which are:
RFC: remote function calls, internal tables are passed on "with references". A copy of the table is copied to thee target system, updates performed using only the one log table. Data transfer may be synchronous or asynchronous. Batch input sessions are also a possibility.
EDI: electronic data interchange; converts the temporary structures to EDI messages and vice-versa (SAP does not provide this element of the EDI architecture). Automatic processing of business transactions.
4. Understand/Describe the data flow of a Dialog Step.
First, user input is accepted by SAPGUI. SAPGUI is the SAP software that runs on your PC. SAPGUI converts the users input into process requests that the dispatcher can understand, and then sends the process requests to the dispatcher.
After receiving the process request the dispatcher places it into request queues called the Roll and Page areas.
As work processes become available the dispatcher dispatches the queued process request to the appropriate work process. The actual processing takes place in the work process.
Work processes are specialized components of the SAP software that are designed to very specific activities. For example if the dispatcher receives a process request to print a report, that process request will inevitability find its way to the work process that manages the print spool.
When processing is complete, the result of a work process is returned, via the dispatcher, to the SAPGUI. The SAPGUI interprets the received data and generates the output screen for the user.
5. Which work process triggers database changes?
Online work processes can directly trigger database changes, but the update work process is normally local to the database and thus has shorter communication path.
The SAP Dispatcher is the proprietary control agent which, along with the respective operating system, manages the resources for the R/3 applications.
The main tasks of the dispatcher are:
1) Equal distribution of transaction load to the work processes.
2) Management of buffer areas in main memory.
3) Integration of the presentation level.
4) Organization of communication activities.
2. What is a Work Process and identify the ones within R3.
A work process is where individual dialog steps are actually processed and the work is done. Each work process handles one type of request:
online, (process only one request at a time),
background, (started at a specified time),
update, (primary, U1, or secondary U2),
enqueue, (lock mechanism)
spool, (generated online or during background processing for printing).
3. In R3 there are 2 services that deal with communication. Identify and explain their function.
1) Message service: used by the application servers to exchange short internal messages, all systems communication.
2) Gateway service: enables communications between R/3, R/2 and external applications, using the CPI-C protocol. Also used by EDI, RFC, which are:
RFC: remote function calls, internal tables are passed on "with references". A copy of the table is copied to thee target system, updates performed using only the one log table. Data transfer may be synchronous or asynchronous. Batch input sessions are also a possibility.
EDI: electronic data interchange; converts the temporary structures to EDI messages and vice-versa (SAP does not provide this element of the EDI architecture). Automatic processing of business transactions.
4. Understand/Describe the data flow of a Dialog Step.
First, user input is accepted by SAPGUI. SAPGUI is the SAP software that runs on your PC. SAPGUI converts the users input into process requests that the dispatcher can understand, and then sends the process requests to the dispatcher.
After receiving the process request the dispatcher places it into request queues called the Roll and Page areas.
As work processes become available the dispatcher dispatches the queued process request to the appropriate work process. The actual processing takes place in the work process.
Work processes are specialized components of the SAP software that are designed to very specific activities. For example if the dispatcher receives a process request to print a report, that process request will inevitability find its way to the work process that manages the print spool.
When processing is complete, the result of a work process is returned, via the dispatcher, to the SAPGUI. The SAPGUI interprets the received data and generates the output screen for the user.
5. Which work process triggers database changes?
Online work processes can directly trigger database changes, but the update work process is normally local to the database and thus has shorter communication path.
Interview Questions on R/3’s system architecture
1. What guarantees the integration of all the application modules?
The R/3 Basis system. It guarantees that the application modules are platform- independent. The R/3 Basis software provides the run-time environment for the R/3 applications, ensures optimal integration, defines a stable architectural frame for system enhancements, contains the administration tools for the entire system, offers interfaces for decentral system components and non-SAP products. One of the Basis system's main tasks is to guarantee the portability of the complete system.
2. What are the central interfaces of the R3 system?
Presentation Interface, Database Interface, Operating System Interface
3. Which interface controls what is shown on the PC?
Presentation interface.
4. Which interface converts SQL requirements in the SAP development system to those of the database?
Database interface.
5. What is a Transaction?
A series of logically connected dialog steps, usually consisting of several screens.
Monday, November 17, 2008
R/3 System Startup Procedure and Stopping Procedure
Starting Procedure:
For starting SAP system, internally it follows the following procedure:
Database will started first, then Message Server , next Dispatcher and finally Work Processes.
DB - Msg Server- Dispatcher - WP
Stoping Procedure:
For Stopping SAP System, internally the system follows the following procedure:
WP - Dispatcher - Msg Server - DB
For starting SAP system, internally it follows the following procedure:
Database will started first, then Message Server , next Dispatcher and finally Work Processes.
DB - Msg Server- Dispatcher - WP
Stoping Procedure:
For Stopping SAP System, internally the system follows the following procedure:
WP - Dispatcher - Msg Server - DB
Start Profiles
Startup Profile consists of the starting procedure information of the R/3 system.
Start Profile resides in all application servers including central instance.
Start Profile resides in all application servers including central instance.
Instance Profiles
Instance Profile consists of the configuration information of its respective application server. Instance profile exists in all the application servers including central instance also.
Modifications performed to the Instance Profile parameters will reflect only in its respective application servers (Instance).
Modifications performed to the Instance Profile parameters will reflect only in its respective application servers (Instance).
Default Profiles
Default Profile consists of the global parameter values.
There will be only one default profile in the entire R/3 system.
Modifications performed to the Default Profile will effect the whole R/3 system.
There will be only one default profile in the entire R/3 system.
Modifications performed to the Default Profile will effect the whole R/3 system.
System Profiles
Profiles are 3 types :
1) System Profiles
2) User Profiles
3) Client Profiles
System Profiles:
A system profile is an operating system file which consists of the R/3 system configuration information.
path : usr/sap/SID/SYS/Profile
System Profiles are 3 types:
i) Default Profile
ii) Instance Profile
iii) Start Profile
1) System Profiles
2) User Profiles
3) Client Profiles
System Profiles:
A system profile is an operating system file which consists of the R/3 system configuration information.
path : usr/sap/SID/SYS/Profile
System Profiles are 3 types:
i) Default Profile
ii) Instance Profile
iii) Start Profile
Friday, November 14, 2008
Main Concepts in SAP BASIS
Profiles
Operation Modes
Background Jobs
Spool Administration
User Administration
Kernel Upgradation
Client Administration
Database Administration
Operation Modes
Background Jobs
Spool Administration
User Administration
Kernel Upgradation
Client Administration
Database Administration
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