HiSSDS and SDS are same. previusly SDS is launched ACE Model. Now microsoft will planning to launch SDS RDBMS Model of SDS. Yes you can use SDS on Azure Platform. but you have to wait for launching of relational model of SDS, microsoft going to stop SDS ACE model.From url http://msdn.microsoft.com/en-us/library/dd557595.aspx you can find Preliminary SDS RDBMS Model Document.RegardsKapil