What is OSS - Online SAP Support Notes ?
OSS stands for Online SAP Support notes for SAP System users.
These OSS notes can be considered as patches or hotfix for critical problems in SAP Systems.
You can apply OSS notes as a solution to critical problems and bugs in SAP systems.
A SAP ABAP developer or administrator can reach and read SAP OSS Note using SNOTE transaction. And other method to read SAP OSS notes online is using the Search SAP Notes web pages at SAP Support Portal.