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Mobile Software Development Framework

4/14/2009

Richard Yang

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Admin.

Homework 4

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Recap

What are the major considerations in developing a software environment and application framework for mobile wireless applications? Handle heterogeneous devices/configurations Efficient (memory, battery, …) Easy programming for event-driven

programming …

Overview

Software framework for mobile applications is a quite large topic, we will see three representative examples TinyOS J2ME Android

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TinyOS

http://www.tinyos.net/tinyos-1.x/doc/tutorial/

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Hardware

Assembled from off-the-shelf components

4Mhz, 8bit MCU (ATMEL) 512 bytes RAM, 8KB ROM

Devices serial Port temperature sensor & light

sensor 900Mhz Radio (RF monolithics)

• 10-100 ft. range LED outputs

1.5” x 1.5”

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Schematic Diagram of a Mote

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Sample Application: Environment Monitoring

Environment monitoring, e.g., measure temperature, lighting

values/events periodically transmit measurements/events

to a base station forward data for other nodes that are out of

range of the base station

…

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Requirements on Software Dev. Framework

Small foot print devices have limited

memory and power resources

Support one application at a time but flexible reprogramming

Flexible configuration of attached devices

TinyOS Application Dev. Framework

Basic principle: Generate customized OS + application for each given scenario

We say each generated scenario generates a tinyOS

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Schematic Diagram

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TinyOS: Software Components

A tinyOS consists of one or more components linked together software components motivated by hardware

component

Each component specifies that it provides some interfaces

• allows other components to control it also uses some interfaces

• control other components

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Interface

An interface declares a set of

functions called commands that provider must implement and

another set of functions called events that the interface user must implement

A uses interfaces I1 and I2

B provides I1 C provides I2

commands events commands eventsI1 I2

C provides I3

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Interface: Examples

StdControl.nc

interface StdControl {  command result_t init();  command result_t start();  command result_t stop();}

Timer.nc

interface Timer {

command result_t start(

char type,

uint32_t interval); 

command result_t stop(); 

event result_t fired();

}

ADC.nc

interface ADC {

async command result_t getdata(); 

async command result_t getContinuousData(); 

event result_t dataReady(uint 16_t data);

}

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TinyOS Component: Implementation

Component contains: commands and event

handlers• can invoke lower level

commands, but cannot block

• event handler can signal higher level signals while command cannot

frame (storage)• statically allocated, fixed

sized to know memory requirement and avoid overhead of dynamic allocation

Component

Internal StateInternal Tasks

Commands Events

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Linking Components

Two types of components:

modules: individual components

configurations : assemble components together, connecting interfaces (objects) used by components to interfaces (objects) provided by others

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Example Application

A simple TinyOS application which periodically reads in the light intensity value, computes a moving average, displays it on the LEDSee SenseTaskM.nc

SenseTask.nc

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TinyOS Execution Model

Concurrency model: only two threads long running tasks that can be interrupted by hardware

event handlers

Tasks perform the primary computation work commands and event handlers post tasks call lower level commands signal higher level events schedule other tasks within a component

Each task is atomic with respect to other tasks run to completion, but can be preempted by events the task scheduler is a simple FIFO scheduler

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Running tinyOS Program make mica ncc -o main.exe -target=mica SenseTask.nc avr-objcopy --output-target=srec main.exe

main.srec Use uisp to install

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A More Complete Sample Application Sensor network

monitoring monitor temperature and

light conditions periodically transmit

measurements to a base station

sensors can forward data for other sensors that are out of range of the base station

dynamically determine the correct routing topology for the network

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Internal Component Graph

RFM

Radio byte

Radio Packet

UART

UART Packet

I2C

Temp

Light

Active Messages

Clocksbit

byte

packet

Ad hoc Routing Applicationapplication

HW

SW

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Message Send Transition

Total propagation delay up the 5 layer radio communication stack is about 80 instructions

Timing diagram of event propagation

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Evaluation: Storage

Component Name Code Size (bytes)

Data Size (bytes)

RoutingAM_dispatchAM_temperatureAM_lightAMRADIO_packetRADIO_byteRFMLightTempUARTUART_packetI2C

884078

1463563348103108464

196314198

00

328

4040

81111

408

Processor_initTinyOS schedulerC runtime

17217882

3016

0

Total 3450 226

Scheduler only occupies 178 bytes

Complete application only requires 3 KB of instruction memory and 226 bytes of data (less than 50% of the 512 bytes available)

Only processor_init, TinyOS scheduler, and C runtime are required

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Evaluation: Timing

Operations Cost (cycles)

Time (µs)

Normalized to byte copy

Byte copy 8 2 1

Post an Event

Call a Command

Post a task to scheduler

Context switch overhead

10104651

2.52.5

11.512.7

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1.251.25

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Interrupt (hardware cost) 9 2.25 1

Interrupt (software cost) 71 17.75

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Discussion

What would we need to extend to tinyOS if we were to use it for writing mobile applications for mobile phones and PDAs?

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Java2 Micro Edition (J2ME)

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Java Platforms

Java2 is divided into three platforms J2EE (Java2 Enterprise Edition)

• business applications

J2SE (Java2 Standard Edition)• general applications

J2ME (Java2 Micro Edition)• small devices such as mobile phone, PDA, car

navigation

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J2ME

Based on Java

Uses “versioning” to avoid using lowest common denominator

Uses java virtual machines to mask device heterogeneity

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J2ME Versioning To accommodate heterogeneous mobile

devices, define configurations and profiles

http://developers.sun.com/techtopics/mobility/getstart/articles/survey/

-A configuration provides fundamental services for a broad category of devices (e.g., lang, io, util)

- A profile supports higher-level services common to a more specific class of devices or market (e.g., life cycle, GUI)

-An optional package adds specialized services that are useful on devices of many kinds, but not necessary on all of them

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J2ME

128-512K mem16-32 bit proc

Upto 2M mem32 bit proc

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Two Available J2ME Configurations Connected Limited Device Configuration (CLDC)

160 KB to 512 KB of total memory available 16-bit or 32-bit processor low power consumption and often operating with

battery power connectivity with limited bandwidth many Java features deleted, e.g., floating point, finalize examples: cell phones, certain PDAs

Connected Device Configuration (CDC) 2 MB or more memory for Java platform 32-bit processor high bandwidth network connection, most often using

TCP/IP examples: set-top boxes, certain PDAs

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Available J2ME Profiles

Mobile Information Device Profile (MIDP) delivers an enhanced user interface, multimedia and game

functionality, end-to-end security, and greater networked connectivity to mobile phones and entry level PDAs

Foundation Profile set of Java APIs that support resource-constrained devices

without a standards-based GUI system

Personal Profile Together with CDC and Foundation Profile, Personal Profile

provides a complete application environment for the high-end PDA market. Personal Profile contains the full set of AWT APIs, including support for applets and Xlets

Personal Basis Profile provides a J2ME application environment for network-

connected devices supporting a basic level of graphical presentation

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Mobile Phone Framework

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Typical J2ME Technology Stack

Mobile Information

Device Profile

KVMCLDC = KVM + J2ME Core

APIs in this

example DSP chip(e.g., ARM)

J2ME core APIs

YourMIDlet

Yellow Pages, train schedules and ticketing, games…

UI, HTTP networking...

Threads, no Floats…

32-bit RISC, 256K ROM, 256K Flash, 64K RAM

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CLDC Available Packages

java.lang java.util java.io javax.microedition.io

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CLDC Classes Boolean Byte Character Class Integer Long Math Object Runnable Runtime Short String StringBuffer System Thread Throwable

Calendar Date Enumeration Hashtable Random Stack TimeZone Vector

ByteArrayOutputStream ByteArrayInputStream DataOuput DataInput DataInputStream DataOutputStream InputStream InputStreamReader OutputStream OutputStreamWriter PrintStream Reader Writer

java.lang java.util java.io

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Networking Connection

Based on a framework called the Generic Connection Framework (GCF)

GCF consists of an interface hierarchy that is extensible a connection factory, and uses Standard Uniform Resource Locators

(URLs) to indicate the connection types to create• scheme://user:password@host:port/url-path;parameters • e.g.socket://www.j2medeveloper.com:80file:///myResourceFile.resdatagram://www.j2medeveloper.com:7001sms://+12034326400

http://developers.sun.com/techtopics/mobility/midp/articles/genericframework/

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MIDP Hardware

Memory (added to CLDC memory) 128 KB non-volatile for MIDP components 8 KB non-volatile for application persistent

data 32 KB volatile for KVM

Display screen 96x54 display depth 1-bit pixel shape (aspect ratio) 1:1

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MIDP Hardware

Input (one or more)one-handed keyboard (ITU-T phone

keypad) two-handed keyboard (QWERTY keyboard)or touch screen

Networking two-way wireless possibly intermittent limited bandwidth

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MIDP Packages

java.io java.lang java.util javax.microedition.io javax.microedition.lcdui javax.microedition.rms javax.microedition.midlet

javax.microedition.lcdui.game javax.microedition.media javax.microedition.media.contr

ol javax.microedition.pki

addition in version 2.0version 1.0

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MIDP Application Model

An MIDP application is called a MIDlet similar to the J2SE applet GUI based

MIDlet suites – for applications that share resources or data

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MIDP: Application Lifecycle

MIDlets move from state to state in the lifecycle, as indicated

start – acquire resources and start executing

pause – release resources and become quiescent (wait)

destroy – release all resources, destroy threads, and end all activity

Pause

Active

Destroyed

startApp

destroyApp

pauseApp

destroyApp

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HelloWorldMIDlet.javaimport javax.microedition.midlet.*;import javax.microedition.lcdui.*;

public class HelloWorldMIDlet extends MIDletimplements CommandListener {

private Command exitCommand;private Display display;private TextBox t;

public HelloWorldMIDlet() { display = Display.getDisplay(this);exitCommand = new Command("Exit", Command.EXIT, 2);t = new TextBox(“CS434", "Hello World!", 256, 0);t.addCommand(exitCommand);t.setCommandListener(this);

}public void startApp() { display.setCurrent(t); }public void pauseApp() { }public void destroyApp(boolean unconditional) { }public void commandAction(Command c, Displayable s) {

if (c == exitCommand) {destroyApp(false);notifyDestroyed();

}}

}

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Developing J2ME Applications

Identify the devices Identify the profiles supported by devices

using the MID profile, the application will target cell phones and pagers

Develop application install jdk, a package supporting the wireless

target (e.g., Sun Wireless Toolkit for CLDC) debug using a simulator for deployment, preverify by pre-generating

“stack map”

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Stack map attribute increases the size of a classfile by appro. 5% but substantially reduces device mem and CPU usage

Deploying: Two-Phase Class File Verification Process

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Deploying

Generate deployment files: two files• Java Application Description file (.jad)• Java archive file (.jar)

Upload .jad and .jar to the device or a server where the device can download the application

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Over-The-Air Application Loading Process

Web Page

JAMDownloadsApp

UserSelectsApp

AdvertiseApp on Web Page

Network Transfer Java ApplicationManager

(Name,Version,

Size,…)

Jar File

DescriptorFile

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Summary: J2ME

Scale down a popular programming environment to ease learning

Use virtual machines to mask (some) device heterogeneity

Use versioning to avoid using lowest common denominator

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Windows .NET Compact Framework Similar to J2ME Scales down a popular programming environment to ease

learning the .NET CF is a subset of the full .NET framework with some additions designed for resource constrained devices 1,400 classes for .NET CF vs. 8,000 for full 27 UI controls for .NET CF vs. 52 for full 1.5 MB for .NET CF vs. 30 MB for full

Uses versioning to avoid using lowest common denominator pocket PC pocket PC phone version smart phone version

Uses virtual machines to mask device heterogeneity programming languages compile to MSIL

• MSIL is JIT compiled on the device• MSIL code is smaller than native executables• MSIL allows your code to be processor independent

Andriod

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Andriod

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Andriod Features

Linux kernel as foundation

Java based framework (J2SE not J2ME)

Dalvik Virtual machine

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Application Framework: Key Concepts

Activity Visible screen

Service Background services

Content provider Shared data

Broadcast receivers Receive and react to broadcast events

Intent Activating component

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