Android Installation

Android Installation

1. Options

You have different options to install the Android development tools. The simplest way is to download a full packaged pre-configured Eclipse.

For other options please see Android installation

2. Standalone ADT installation

Google provides a pre-packaged and configured Eclipse based

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Using Resources

1. Reference to resources in code

The Resources class allows to access individual resources. An instance of Resources can get access via the getResources() method of the Context class.

The Resources class is also used by other Android classes, for example the following code shows

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Resources

1. Resources

Android supports that resources, like images and certain XML configuration files, can be keep separate from the source code.

These resources must be defined in the res directory in a special folder dependent on their purpose. You can also append additional qualifiers to the folder name to indicate

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Android Application Architecture

1. AndroidManifest.xml

The components and settings of an Android application are described in the AndroidManifest.xml file. For example all Activities and Services of the application must be declared in

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Android Development Tools

1. Android SDK

The Android Software Development Kit (SDK) contains the necessary tools to create, compile and package Android application. Most of these tools are command line based.

The Android SDK also provides an Android device emulator, so that Android applications can be tested without a real Android phone. You can create Android virtual devices (AVD) via

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Other Android components

Android has several more components which can be used in your Android application.

Intents

Intents are asynchronous messages which allow the application to request functionality from other components of the Android system, e.g. from Services or Activities. An application can call a component directly (explicit Intent) or ask the Android system to evaluate registered components based on the Intent data (implicit Intents ). For example the application could implement sharing of data via an

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1. What is Android?

Android Operation System:

Android is an operating system based on Linux with a Java programming interface.

The Android Software Development Kit (Android SDK) provides all necessary tools to develop Android applications. This includes a compiler, debugger and a device emulator, as well as its own virtual

What is page thrashing?

Some operating systems (such as UNIX or Windows in enhanced mode) use virtual memory. Virtual memory is a technique for making a machine behave as if it had more memory than it really has, by using disk space to simulate RAM (random-access memory). In the 80386 and higher Intel CPU chips, and in most other modern microprocessors (such as the Motorola 68030, Sparc, and Power PC), exists a piece of hardware called the Memory Management Unit, or MMU.

The MMU treats memory as if it were composed of a series of “pages.” A page of memory is a block of contiguous bytes of a certain

What are short-, long- and medium-term scheduling?

Long term scheduler determines which programs are admitted to the system for processing. It controls the degree of multiprogramming. Once admitted, a job becomes a process.

Medium term scheduling is part of the swapping function. This relates to processes that are in a blocked or suspended state. They are swapped

What is a binary semaphore? What is its use?

A binary semaphore is one, which takes only 0 and 1 as values. They are used to implement mutual exclusion and synchronize concurrent processes.

Explain Belady's Anomaly.

Also called FIFO anomaly. Usually, on increasing the number of frames allocated to a process' virtual memory, the process execution is faster, because fewer page faults occur. Sometimes, the reverse happens, i.e., the execution time increases even when more frames are allocated to the process. This is Belady's Anomaly. This is true for certain page reference patterns.

Explain the concept of Reentrancy.

It is a useful, memory-saving technique for multiprogrammed timesharing systems. A Reentrant Procedure is one in which multiple users can share a single copy of a program during the same period. Reentrancy has 2 key aspects: The program code cannot modify itself, and the local data for each user process must be stored separately. Thus, the permanent part is the code, and the temporary part is the pointer back to the calling program and local variables used by that

List out some reasons for process termination.

• Normal completion


• Time limit exceeded


• Memory unavailable


• Bounds violation


• Protection error


• Arithmetic error


• Time overrun


• I/O failure


• Invalid instruction


• Privileged instruction


• Data misuse


• Operator or OS intervention


• Parent termination.

What is time-stamping?

It is a technique proposed by Lamport, used to order events in a distributed system without the use of clocks. This scheme is intended to order events consisting of the transmission of messages.

Each system 'i' in the network maintains a counter Ci. Every time a system transmits a message, it increments its counter by 1 and attaches the time-stamp Ti to the message. When a message is