SAP ABAP Developer vs. SAP ABAP IS-U Developer

Hi Experts,

I am very curious to know what an SAP ABAP developer does in an IS-U company. Will he/she use any different tables while coding other than ABAP standard tables like VBAK, VBAPu2026.etc? What is the difference between a normal SAP ABAP Developer vs. SAP ABAP IS-U Developer? What extra qualifications does he/she should have in order to get a SAP ABAP IS-U job? Is there any websites which has documentations or tutorials or sample codes on SAP ABAP IS-U other than saphelp.com? I have searched about SAP ABAP IS-U on SDN and other sites. But I couldnu2019t find any useful info. Please advice.

Thanks,

Nani.