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Introduction of Android OS
Transcript of Introduction of Android OS
Introduction of Android OS
Android is a Linux-based operating system and software platform for smart phones and tablets.
Android Inc was founded in Palo Alto of California, U.S. by Andy Rubin, Rich miner, Nick sears and Chris White in 2003.
The first commercially available phone to run Android was the HTC Dream, released on October 22, 2008 With Android Version 1.0
Inter-process communication (IPC) is a set of programming interfaces that allow a programmer to coordinate activities among different program processes that can run concurrently in an operating system.” Binder is an Android-specific inter-process communication mechanism. Binder takes a different approach with the constructs used, to better support Android interface definition language (AIDL).
Binder refers to a kernel memory which is shared between all processes. This minimize the overhead caused by memory copy.
Android has security feature built into the operating system that significantly reduce the impact of security issues.
The Android system is designed so typically process with default system and file access permissions avoid difficult decisions about security.
The Android Application Sandbox isolates application data and code execution from other application. Each application with implementations of common security functionality such as cryptography, permissions.
It also allows user-granted permissions to restrict access to system feature and users data, with encrypted file system that can be
enabled to protect data on lost
Open source – Free development platform
Built in components can be improved
Android has been selected by many hardware manufacturers to run on a wide range of devices.
Android is a User Friendly OS.
The above figure shows the diagram of Android Architecture. The Android OS can be referred to as a software stack of different layers, the kernel and low level tools, native libraries, the Android Runtime, the framework layer and on top of all the applications. where each layer is a group of several program components. Together it includes operating system, middle ware and important applications. Each layer in the architecture provides different services to the layer just above it.
Threads have been an essential part of operating system. Most modern operating systems support threads, and Android is no exception. Threads are the core of any multitasking operating system and can be considered as smallest unit of process running within a main process. This method enable the purpose of parallel execution of the application which result in quick and responsive to the user.
Android is truly open, free development platform based on Linux and open source.Handset makers can use & customize the platform without paying a royalty.
How deadlock is handled
Deadlock is a common problem in multiprocessing systems.
And there are 3 ways most of the OS uses to deal with deadlock they are as follow:
o Prevent or avoid
o Detect and recover
o Ignore the problem
Android use second option to handle the deadlocks, as it is hard to prevent from occurring deadlocks it let deadlocks to occur. Then system detect that a deadlocks has occurred and try to recover from it. Detecting a deadlocks is easily possible since each process has locked and are waiting for one another. Now it has to recover, an algorithm has to tracks resource allocation and process states, it goes back and start over again with one or more of the processes in order to remove the deadlock.
A thread has the following states:
• Blocked : The thread is blocked and waiting for a lock
• New: The thread has been created, but has never been started. A thread is started by calling its start () method.
• Runnable: The thread may be run.
• Terminated: The thread has been terminated.
• Timed waiting: The thread is waiting for a specified amount of time.
• Waiting: The thread is waiting.