clayj said:
Who says it has to have a hard drive? Throw a couple of GB of flash RAM in there, give it enough memory to run several applications and data simultaneously...
That helps some, but it throws a lot more money at the problem, particularly if you're thinking about something large enough to hold Microsoft-code-(in)efficency-sized applications: at Apple's price of $25 per GB, a 20GB flash RAM analog would retail for $500 for just this one component.
From a power perspective, the backlit color display is a major consideration. For example, Apple iPod nano has a 3.7V, 330 mAh battery, which is able to power the device for only 2 hours when in video playback mode.
Now grow that tiny screen into something 4.5" x 8" or thereabouts, and you probably have ~16x the power draw...doing the math, you need around 5WH for 2 hours runtime...30WH for 12 hours. Fine, you've now saved 18WH, which means instead of needing a 2lb battery for 48WH, you're down to a 1.3lb battery.
...and then use a Wi Fi connection to access data across the Internet...
Standard 802.11b is 1W transmitter. At 80% RF conversion efficency (very high) and times 12 hours runtime, it will burn 15WH of power...which sums to 45WH required, so you're back up to needing a ~2lb battery again.
you'd almost cut battery usage down to the level of a cellphone.
My cellphone doesn't have 12 hours of talk time. And when it talk mode, its rating isn't assuming that its LCD display is illuminated the whole time.
Overall, the game that MS is going to have to play is the "up to..." X hours of operation. This is why I joked that it is probably all in standby mode. If MS's 12 hour claim comes through, the acid test will be to see if it can play the entire LOTR trilogy on a single charge.
-hh