Ever so gently, we're starting to peel away the layers of mystery surrounding the A4 system-on-chip that powers Apple's fancy new slate device. iFixit, helped by reverse engineering firm Chipworks, have gone to the trouble of both dissecting and X-raying the iPad's central processing hub in their quest to lift the veil of ignorance. Their findings confirmed that the A4 is built using a "package on package" method, meaning that the 256MB of Samsung-provided SDRAM is stacked immediately atop the CPU, which is noted as being reductive to both l