[RFC-004] Comment-2

Organization: George Mason University

Comments on DAP2 protocol

In past a few months, I implemented a CEOP server which function as a data converter to serve NASA Satellite data to OpenDAP clients. From my experience of implementing CEOP server, I feel DAP2 protocol is easy to follow. But I feel like its would be more convenient and clear to add following in it:

• add a query method for the DAP client to query a DAP server what data sets the server can offer to client. So the client only need to know the servers url and use this query it will get all data sets that the server serves.
• In the protocol, please be more specific on how the server returns the each data type to DAP clients. Make it as a standard for DAP servers and clients. Currently in implementation , server need to pad the 16 bits short ( in Java) data type to 4 bytes int ( 32 bits ) for each data value and then send it back to client. But then byte data type is padded only in the end to 4s multiples. The padding method is not described in the protocol and this confuses the DAP server developer who know little about the DAP clients implementation.