Found this chart on asymco.com in an article comparing the new iPad to the macbook air of four years ago. It’s generally a fair comparison, but…
1) The 2008 macbook air actually had an ambient light sensor as well to automatically adjust keyboard backlight and screen brightness.
2) Crude Geolocation is possible to do via software if the computer is connected to the internet.
But I’m nitpicking here. There’s no doubt that progress is not linear - it is usually exponential. The website comes to the conclusion that the technological gap between the two platforms is about 4 years. This is an interesting conclusion.
"The new iPad now exceeds the total display resolution, has similar speed and storage capacity while having twice the battery life of the thinnest laptop of four years ago. It also has very high quality cameras and GPS and cellular network connectivity which have yet to appear on mainstream PCs. It’s still a lot smaller and half the price and has a larger selection of available software titles at prices a fraction of its elder cousin."
Well, I’d actually argue that the main advantage the iPad has over the mac is that of better, higher quality software. Because the iPad is such a clean sheet design, borrowing only what it absolutely has to borrow from the mac and no more, it is able to become a highly optimized, zero-legacy platform. This is something the mac can no longer do as an aging and wider-spectrum (all types of different hardware configurations to deal with) platform. There are only 3 iPad generations, with each only having 2 major hardware configurations in terms of connectivity. This makes managing and writing the software that much easier and better. iPad also deals in a whole new paradigm of computing based on natural interactions (direct multi-touch and, now, voice) which are simpler, and thus add to its advanced-ness.
The problem for Asymco is that its is usually hard to quantify gains coming form software improvements. iOS has made possible (in fact, necessary) for us to have iCloud, for example. This adds a lot of quality to one’s computing, but its not easy to compare the gains from the old days when we had macs and no iCloud.
In conclusion, it seems to me that the gap is probably narrower than 4 years. I’d say maybe 2, or 3 at the most.