Definition
End of Service Life, which IBM labels End of Standard Service (EOSS) in its own lifecycle notices, is the point at which IBM stops issuing new firmware, program temporary fixes, and code updates for a hardware generation, and standard IBM service contracts on that platform wind down. Systems do not stop running on this date. What stops is new code coming from IBM.
Once a generation passes EOSL, buyers who need continued formal support typically move to a third-party maintenance provider, plan a migration to a currently supported generation, or accept the increasing operational risk of running unsupported hardware. The EOSL date, not the earlier End of Marketing date, is the one that should actually drive a support or upgrade decision.