SAP Basic Understanding Regarding to Spool

Basic Understanding Regarding to Spool

Explain on Local Printing, Remote Printing, Front End Printing.
Concept of logical server and SAPLPD.

Tcode : SPAD

Local Printing means that your spool server (R/3) and print manager (OS) are running on the same machine and the printer is connected locally or via network connection to the Print manager (OS).
Access Method for local printing :
C : Direct operating system call - for windows
L : connect locally via lp/lpr with signal - for unix

Remote Printing means that your spool server (R/3) and print manager (OS) are running on different machine and the printer may be connected locally or via network connection to the print manager (OS).
Access Method for Remote printing :
U : Print on LPDHOST via berkeley protocol - for windows and unix
S : Print on LPDHOST via SAP protocol - for windows

Front end printing means that printer is connected to the front end system. there is no need to define the printer on the SAP system.
Access method for front end printing :
F : Print on front end (locally) via SAPLPD

Logical Server are mapped to the physical server or another logical server. These servers are used for load balancing purpose.

SAPLPD daemon is an interface between Spool server (R/3) and Print Manager (OS). when using the access method U,S and F this daemon program should be running on the print manager (OS) (in case of U,S) and on the front end system (in case of F).