can not find HostSystem mob on vpshere mob webpage.

Hello,

     I am trying to check some iscsi infomation, I followed this discussion How to get the iscsi initiator name(iqn) of esx using vsphere sdk , I login into the (version 6.0) vcenter's mob webpage and entered ServiceContent entity, but I can not find HostSystem entity.

    anyone knows where is the HostSystem entity is ? please help , thanks in advance.

     this is what my ServiceContent shown.