Few things in life are free and even if something appears to be free, it is merely a matter of perception.
On the Internet, you may pay for the consumption of content by viewing ads. Free smartphone apps also include ad viewing most of the time. However, apps also require you to pay with battery power as researchers from Purdue University have found that ads are responsible for the lion's share of an app's thirst for power.
When evaluating the power usage of ads in six popular apps including Angry Birds, Facebook and Android Browser, they found substantial power usage of the ads. For example, the ad module in Angry Birds consumes about 75 percent of the entire power, meaning the actual game consumed only 25 percent. The high power consumption is caused by ad modules that track the user's geographical location, send information about the user to advertisers and download ads. The researchers will be providing details about their findings in a paper that is scheduled to be published during the EuroSys 2012 conference, which takes place from April 10 to 13 in Bern, Switzerland.
Other factors that cause energy drain include inefficient programs and software glitches called "energy bugs," said Charlie Hu, a Purdue University professor of electrical and computer engineering. "The past assumption has been that, whenever you see usage you have power consumption, and when there is no usage there is no power consumption," Hu said. "This does not hold true for smartphones."
The scientist said that that simple data network usage results in an additional "tail" after the usage. "The ad module in Angry Birds obviously uses 3G for network uploading and downloading, while the game itself did not, which is why we blame the ad module for the tail," he explained.
In their paper the researchers also provide a method to "improve energy efficiency with a technique that has been shown to reduce the energy consumption of four apps by 20 percent to 65 percent." while they did not provide details yet, the researchers said that they aim to develop an "energy debugger that automatically pinpoints flaws in software and fixes them without the intervention of a human software developer."