Recent uproar over Panic Software’s discovery of ARM processor and 256MB of RAM in Apple’s Digital AV adapter provoked rumours that Apple might be using its AirPlay technology to stream the content over the cable to large displays but things have been described in a more clear way by an anonymous Apple employee of Slashdot Forum about why a simple cable uses such complicated hardware and confirmed through his detailed explanation about the working. Read on for more details
The only similarity between iOS and the Kernel of the adapter seems to the booting of XNU, apart from that there is no launchd nor shell image nor any other utilities. The SoC (System on Chip) directly boots a Daemon code that is designed to accept incoming signals, process them and output them through A/V connectors.
The very reason for using such a technique is that Lightening being a serial bus is not capable of handling raw HDMI signals, the only other way to handle such complex transmission is to tweak the parent hardware, i.e iPhone or iPad or iPod touch, to handle the processing and use a simple lightening cable. Apple wanted the hardware to remain independent of these complexities so that all the variations are handled by the adapter rather than the hardware.
One major advantage of using such a system is that Apple can now product multiple variations of this cable using this technology by just varying the final output port in the adapter. The whole processing is independent of the hardware sending the incoming signal and the output port, both of which can be varied by multiple combinations.