What's the difference of UIView frame and bounds.

UIView and its subclasses all have the properties "frame" and "bounds". What's the difference?

The frame of an UIView is the rectangle, expressed as a location (x,y) and size (width,height) relative to the superview it is contained within.
The bounds of an UIView is the rectangle, expressed as a location (x,y) and size (width,height) relative to its own coordinate system (0,0).

Difference between delegate and data source?

 http://stackoverflow.com/questions/2232147/whats-the-difference-between-data-source-and-delegate

Can't run - was built for 'armv7', but device requires 'armv6' or compatable architecture.

This error may appear when connecting to device from iPhone Sdk 4, (Xcode 3.2.3)

to fix this
in Xcode Project->Edit Active Target
Set the Architectures:Standard(armv6 armv7)