SAP Basis

ADM100 Lesson: Process of a System Logon
Figure 3: Process of a System Logon
After the transfer of the logon screen from the dispatcher to the front end
(notshowninthefigure),SAPGUIsendstheuser’slogondatatothe
instance (step 3 in the above figure). After the dispatcher has determined
a free work process to process the logon, it transfers the logon data to
this work process (step 4). The work process, in turn, checks whether the
received combination of user ID and password is known to the system
using a request to the database (steps 5-8). A positive response from the
database prompts the work process to return the initial screen of the
system to the front end.
During a logon session, the assignment of the user to the instance is
unique. Only during a new logon can the user possibly be assigned to a
different instance by the message server.
Dialog Work Process Multiplexing
The important term work process multiplexing is repeated here. This
property of the system, which means that successive dialog steps for
the same user can be processed in different dialog work processes, has
far-reaching consequences, ultimately including the use of “asynchronous
updates”. The function of request queues can also be explained here.
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