This is 'Windows' we are talking about, which has the highest number of inbox drivers any OS ever had.
Plus for most of the USB devices (like thumb driver, external HDD, Digi Camera, keyboard, mouse, etc.) Windows doesn't need particular driver, there are class drivers, which works just fine with respective class of devices.
The reasons Microsoft built Surface were:
1. MS felt the OEM Win8 tablets not upto the mark with iPad.
2. There is no dedicated OEM working on Win8 tablet.
3. MS thinks there isn't OEM with market perception comparable to Apple in tablet space.
All these issues aren't present in WP8 space, as Nokia has history of marking amazing phones, it is dedicated to WP8 and market perception of Nokia isn't bad in phone space. So it doesn't make sense for Microsoft to make their own phone.
with Win8 and WP8, they both have the same kernel, so for e.g. any device drivers written for one can be used on the other directly without any changes.
Although I agree it's not exactly the same OS, but the most of major OS component are same with special components as per different uses.
astronomy noob here.
Parsec is unit of length= 3.26 light-years per http://en.wikipedia.org/wiki/Parsec.
so what's the measuing unit for expantion rate of unit?
74.3 +/- 2.1 kilometers per second per megaparsec
correspounds to "length per time per length"
so is it
1. Cancelling lengths all it remains is "per time"? which seems wrong.
2. length * length / time?