I want to update my iPad 1 os. How?
If you are using iOS 4 (or earlier) there is no Software Update in Settings. That feature was first added in iOS 5.
To update you will have to connect your iPad to iTunes on a computer (preferably the one you sync with and backup to).
See here: http://support.apple.com/kb/HT4972
The iPad 1 can be updated to iOS 5.1.1
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