Portable Document Format (PDF) is a file format created by Adobe Systems in 1993 for document exchange.
PDF is used for representing two-dimensional documents in a manner independent of the application software, hardware, and operating system.
Adobe Reader 9.0 has lots of new innovated plugins with it.
It can handle modern PDF mechanism.
Download size is 32 MB for Version 9.0. It will occupy 130+ MB in your hard disk after installing it.
If you want to view normal PDF files without having any modern mechanism (just a plain document), do not go for Adobe Reader 9.0.
It will take more time to load for a small plain document in version 9.0.
Look for the following alternatives for viewing small, normal PDF files.