Linked by Kroc Camen on Thu 30th Sep 2010 12:12 UTC
Talk, Rumors, X Versus Y "I am truly shocked that so many people are being duped by BlackBerry's recent announcement of their tablet, the PlayBook. I have read endless comments from people who are saying they can't wait to get this tablet computer. Well, I think I have some bad news for you folks. There is no evidence that the PlayBook exist as advertised. Why do I say this? I will make it brief..."
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RE[4]: Have to agree
by tony on Thu 30th Sep 2010 20:24 UTC in reply to "RE[3]: Have to agree"
Member since:

True, but the operating system can go very far in determining battery life. My Android phone, the Motorola Cliq, has a friggin' huge battery but barely makes it through a day of light browsing once or twice an hour, and a couple of phone calls and texts. Why? It has a low power, efficient processor, and an energy efficient screen so those aren't the culprits. The cell and WiFi radios are no different than any other Motorola smartphone when it comes to power draw, so it's not them either.

No, I'll tell you why: Because it's running the older, less efficient version 1.5 of the OS, and the MotoBlur UI that runs on top of the OS is constantly polling data, even when you set the phone in "Battery Saver" mode. This device is a clear case of the software, not the hardware, running the battery down. I'm looking forward to the 2.1 update mostly for the gain in battery life.

That's the power management functionality aspects of the operating environment, which are higher level functions, not scheduling, I/O ops, or microkernel versus monolithic, etc.

Reply Parent Score: 2

RE[5]: Have to agree
by Neolander on Thu 30th Sep 2010 21:44 in reply to "RE[4]: Have to agree"
Neolander Member since:

Actually, proper scheduling can make devices more power-efficient.

As an example, usual round robin algorithms run software whenever it can run, keeping the processor busy and energy-hungry as long as one task is active and it's not put in a sleep state.

A power-efficient scheduling algorithm could swap out some tasks under certain conditions, so that the processor can be put to rest more often. E.g. pausing a game when it's put in the background in order to read some mail won't hurt its functionality the tiniest bit, and CPU use during the time spent reading the mail will drop from 100% (game running in the background) to a few % (scrolling text from time to time).

Defining which tasks are swapped out can be the role of a high-level API, but as you see the ability to swap a task out and stop scheduling it must first be provided at a low level.

Reply Parent Score: 2