Important Categories of SAP System Properties

RDISP/* Parameters for Dispatcher or processes controlled by the dispatcher (ex: work processes)
ES/* & ZTTA/* Parameters that control extended memory settings
SCSA/* Shared Common System Area settings
ENQUE/* Enqueue work process or standalone enqueue server settings
GW/* Gateway settings
MS/* Message server parameters
INSTANCE* Settings that identify instance or server
ABAP/* Settings that control ABAP program execution, including heap
AUTH/* Authorization specific parameters
LOGIN/* Controls the logon environment (ex multiple sessions)
DBS/<DB Type>/* Parameters related to database
EM/* General system related settings
ICF/* & ICM/* Internet control framework and ICM settings
STAT/* Statistics collector related parameters