FNDSM is executable and core component in GSM ( Generic Service Management Framework discussed above).
You start FNDSM services via application listener on all Nodes in Application Tier in E-Business Suite.
So your apps listener must be up.
Please refer below doc ids to understand in detail about FNDSM
210062.1 - Generic Service Management (GSM) in Oracle Applications 11i
GSM was earlier configured manually in 11i and below is doc id for your reference -
Generic Service Management Configuration Using Applications Context Files (Doc ID 204090.1)
As per below document guide by Oracle -
The Service Manager is a component of the Generic Service Management (GSM) architecture rather than Concurrent Processing, although GSM and Concurrent Processing are closely integrated.
coming onto FNDFS -
this executable is nothing but Report Review Agent, which allows users to view request logs and outputs.
It is default text viewer in Oracle applications. Please refer below for more details -
111383.1 - The Basics About Report Review Agent (FNDFS) on 11i