System Architecture & the ABAP Platform

How many message servers does an SAP system have, and what is its main responsibility?

In HANA's multitenant architecture, what is the special responsibility of the SYSTEMDB?

An in-memory database (IMDB) keeps data in main memory rather than on disk — what two inevitable consequences follow?

In the command field, what do the `/N`, `/O`, and `/NEX` prefixes do?

What is the difference between Open SQL and Native SQL, and what role does the DBI play?

Into what intermediate form is ABAP source compiled before execution, and where is it stored?

All work processes are internally the same executable — what is it called?

How does a single work process crash differ from a dispatcher crash in its impact on the instance?

Why is an application server easy to replace and reinstallable from the installation media if needed?

Which component lets SAP GUI for HTML call business transactions directly from a browser?

When monitoring work processes, how do the scopes of SM66, SM50, and SM51 differ?

What are HANA's two core services, and what does each handle?

What are the length rules for a transaction code?

How does the presence or absence of a UP2 process affect how the UPD process handles V1/V2?

What is the minimum number of dialog (DIA) work processes a dialog instance must have?

What kind of data does the table buffer cache, and what does it never cache?

When does a work process use heap memory, and what are heap memory's drawbacks?

Why can't ICF services be called directly by default, and how do you enable them?

How do you test the system's internet connectivity using the ping service?

Why should production systems use a three-level hardware configuration?

What is the system-wide minimum work process count for the background, update V1, and spool services?

What role does the ICF (Internet Communication Framework) play in the system?

What are the 5 types of work process in a dialog instance?

Which two services run on the central services instance (ASCS), and why must it be protected in production?

What do PBO and PAI mean in the dynpro interface?

What three layers make up the S/4HANA client/server architecture?

Which four components does a client request pass through inside a work process, in order?

In an SAP instance's profile file name (name 2) format, what do D, ASCS, and ERS stand for?

Gateway and ICM run inside a dialog instance — why are they not work processes?

How do V1 and V2 updates differ in priority and rollback behavior?

What is the difference between a technical instance and a dialog instance?

Which transaction and menu path are used to monitor the ICM and view its ports?

What is extended memory, and why does it have a quota?

What database always underlies S/4HANA, and what are its two core characteristics?

What does "enqueue" mean in SAP, and what does the enqueue process do?

What is the identifier of a HANA system called, and what is the instance type identifier on each host?

What do the three-level, two-level, and one-level hardware configurations mean?

What kind of process is the ICM (Internet Communication Manager), and what parameter decides whether it starts?

What does an SAP system physically consist of?

What role does the dispatcher play in an instance?

Where does the SAP Web Dispatcher sit, and what is its main job?

How many gateways and ICMs does each dialog instance have?

What is the valid range for an instance number, and why must it be unique on the same server?

Why are writes more complex in HANA's column-store, and what mechanism eases the write overhead?

What role does the enqueue replication server (ERS) play in a high-availability setup?

Today, what is the only difference between a primary application server (PAS) and an additional application server?

What are the naming rules for an SID (system ID)?