The comparison between the Android operating mechanism JNI, Dalvik, and art. Android L Modify the operating mechanism.

Android L uses the art operating environment by default and is fully compatible with 64-bit mobile processors. Google says it will be twice times more powerful than the previous Dalvik mode, but it will take up more memory space. Android has three modes of operation: JNI, Dalvik, ART. Dalvik is obviously the slowest, the complete JNI pattern is the fastest but the development is difficult, art is in between, and does not affect the existing development model, so Google chose art. Our technical engineers have made a technical interpretation of this:

1)JNI: In the development process, using the compiler in C + + and other languages directly compiled into machine code, run time can take full advantage of system performance, this is the fastest. Both the iOS object C and the Android NDK are this mode.

2)Dalvik: Android L system before all Android version of the operation, using the bytecode, at run time to explain the execution becomes machine can recognize the machine code. This process is relatively slow.

3)ART: The new operating environment launched by Android 4.4, using the Dex2oat tool to directly convert Dex files to machine code files when the app is installed, runs in machine code mode, and can take full advantage of system performance; The improved memory recovery mechanism makes the memory recovery rate in art run mode only 50% in Dalvik runtime mode, and also improves system speed.

Although the speed of the operation has increased, art has its drawbacks as well:

1) The app installation process will be slow;

2) The app takes up more storage space, and the system is more prone to lack of system space.

Google this year to the Android ecosystem security mentioned in a very important position, but the Android L system still has some congenital defects:

1) Malware and viruses continue to grow

Android system has been born, has been suffering from a variety of malicious software, with various types of operating system ROM preinstalled built-in and the application of the market is not strict audit, the Android platform malware and virus number is a straight-up trend. 5 years ago, we began to focus on the malicious behavior of various types of software on Android, set up the cloud of app behavior, and analyze the behavior of all kinds of apps in a dynamic and static manner.

From the monitoring data of CM security, a total of more than 4.5 million malicious samples were found, including malware and viruses. In the first half of 2014, the two growth trend over the 150%,android platform of security warfare is a protracted war.

2) system and third-party software vulnerability only Google patches is not enough

The Android L system adds googleplay support for system patches, but due to the fragmented distribution of Android version and the various custom system ROMs, not all vulnerabilities can be patched by GooglePlay. And for third-party software running on the Android system, there are also a number of vulnerability risks (such as WhatsApp privacy leak vulnerability, Adobe Reader webview Arbitrary code execution Vulnerability, etc.), for these vulnerabilities risk, tightly googleplay patch mechanism, is unavoidable or fully patched, the risk of Android vulnerabilities remains grim.

3) The security of mobile phone theft is increasingly important

The US legislation has boosted smartphones ' support for anti-theft, and this feature has been enhanced in the Android L system to completely prevent two scalping or information theft after a phone theft. According to the US Consumer report (Consumer Reports), more than 3 million smartphones were stolen in the United States in 2013, far exceeding 2012 years in 1.6 million.

4) The education of the privacy protection mechanism takes time according to the CM Security Lab's app behavior Cloud Analytics, there are about 200,000 applications (about 4.4%) Will ask users for unnecessary privacy rights, such as text messages, call log read and write permissions, user location data permissions. These apps secretly get the user's privacy in the background, causing the user's daily whereabouts to be exposed.

The Android l system provides a mechanism to adjust app permissions to avoid the risk of user privacy breaches. For the most common users, learning how to do the underlying settings to manage app permissions also requires a certain education cycle.

This article comes from the network, if there is a violation, please prompt to delete