NW Developer Studio

Hi Experts,

in oder to work on Adapter Modules,I hav to download NW Developer Studio .I hav market place Id, and when I am putting a search , I am getting downloads as SAP Netweaver Developer Studio 2.0 SP 23 . This is a .SAR file of more than 450 MB. I would like to knw is this the software I am lookinf gor, I mean is the software and service pack the same thing?

If yes then how to run this .SAR file.

If No then where do I get to find this SAP Netweaver Developer Studio software, I mean is there any specific link in the market place???

Regards,

Arnab