1 Mobile Software Development Framework 4/14/2009 Richard Yang

2 Admin. r Homework 4

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

Overview r Software framework for mobile applications is a quite large topic, we will see three representative examples m TinyOS m J2ME m Android 4

5 TinyOS

6 Hardware r Assembled from off-the-shelf components r 4Mhz, 8bit MCU (ATMEL) m 512 bytes RAM, 8KB ROM r Devices m serial Port m temperature sensor & light sensor m 900Mhz Radio (RF monolithics) ft. range m LED outputs 1.5” x 1.5”

7 Schematic Diagram of a Mote

8 Sample Application: Environment Monitoring r Environment monitoring, e.g., m measure temperature, lighting values/events m periodically transmit measurements/events to a base station m forward data for other nodes that are out of range of the base station r …

9 Requirements on Software Dev. Framework r Small foot print m devices have limited memory and power resources r Support one application at a time but flexible reprogramming r Flexible configuration of attached devices

TinyOS Application Dev. Framework r Basic principle: Generate customized OS + application for each given scenario r We say each generated scenario generates a tinyOS 10

11 Schematic Diagram

12 TinyOS: Software Components r A tinyOS consists of one or more components linked together m software components motivated by hardware component r Each component specifies that m it provides some interfaces allows other components to control it m also uses some interfaces control other components

13 Interface r An interface m declares a set of functions called commands that provider must implement and m 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 events I1 I2 C provides I3

14 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); }

15 TinyOS Component: Implementation r Component contains: m commands and event handlers can invoke lower level commands, but cannot block event handler can signal higher level signals while command cannot m frame (storage) statically allocated, fixed sized to know memory requirement and avoid overhead of dynamic allocation Component Internal State Internal Tasks CommandsEvents

16 Linking Components Two types of components: m modules: individual components m configurations : assemble components together, connecting interfaces (objects) used by components to interfaces (objects) provided by others

17 Example Application r A simple TinyOS application which periodically reads in the light intensity value, computes a moving average, displays it on the LED See SenseTaskM.nc SenseTask.nc

18 TinyOS Execution Model r Concurrency model: only two threads m long running tasks that can be interrupted by hardware event handlers r Tasks perform the primary computation work m commands and event handlers post tasks m call lower level commands m signal higher level events m schedule other tasks within a component r Each task is atomic with respect to other tasks m run to completion, but can be preempted by events m the task scheduler is a simple FIFO scheduler

19 Running tinyOS Program r make mica r ncc -o main.exe -target=mica SenseTask.nc r avr-objcopy --output-target=srec main.exe main.srec r Use uisp to install

20 A More Complete Sample Application r Sensor network monitoring m monitor temperature and light conditions m periodically transmit measurements to a base station m sensors can forward data for other sensors that are out of range of the base station m dynamically determine the correct routing topology for the network

21 Internal Component Graph RFM Radio byte Radio Packet UART UART Packet I2C Temp Light Active Messages Clocks bit byte packet Ad hoc Routing Application application HW SW

22 Message Send Transition r Total propagation delay up the 5 layer radio communication stack is about 80 instructions Timing diagram of event propagation

23 Evaluation: Storage Component NameCode Size (bytes) Data Size (bytes) Routing AM_dispatch AM_temperature AM_light AM RADIO_packet RADIO_byte RFM Light Temp UART UART_packet I2C Processor_init TinyOS scheduler C runtime Total  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

24 Evaluation: Timing OperationsCost (cycles) Time (µs) Normalized to byte copy Byte copy821 Post an Event Call a Command Post a task to scheduler Context switch overhead Interrupt (hardware cost) Interrupt (software cost)

Discussion r What would we need to extend to tinyOS if we were to use it for writing mobile applications for mobile phones and PDAs? 25

26 Java2 Micro Edition (J2ME)

27 Java Platforms r Java2 is divided into three platforms m J2EE (Java2 Enterprise Edition) business applications m J2SE (Java2 Standard Edition) general applications m J2ME (Java2 Micro Edition) small devices such as mobile phone, PDA, car navigation

28 J2ME r Based on Java r Uses “versioning” to avoid using lowest common denominator r Uses java virtual machines to mask device heterogeneity

29 J2ME Versioning r To accommodate heterogeneous mobile devices, define configurations and profiles -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

30 J2ME K mem bit proc Upto 2M mem 32 bit proc

31 Two Available J2ME Configurations r Connected Limited Device Configuration (CLDC) m 160 KB to 512 KB of total memory available m 16-bit or 32-bit processor m low power consumption and often operating with battery power m connectivity with limited bandwidth m many Java features deleted, e.g., floating point, finalize m examples: cell phones, certain PDAs r Connected Device Configuration (CDC) m 2 MB or more memory for Java platform m 32-bit processor m high bandwidth network connection, most often using TCP/IP m examples: set-top boxes, certain PDAs

32 Available J2ME Profiles r Mobile Information Device Profile (MIDP) m delivers an enhanced user interface, multimedia and game functionality, end-to-end security, and greater networked connectivity to mobile phones and entry level PDAs r Foundation Profile m set of Java APIs that support resource-constrained devices without a standards-based GUI system r Personal Profile m 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 r Personal Basis Profile m provides a J2ME application environment for network-connected devices supporting a basic level of graphical presentation

33 Mobile Phone Framework

34 Typical J2ME Technology Stack Mobile Information Device Profile KVM CLDC = KVM + J2ME Core APIs in this example DSP chip (e.g., ARM) J2ME core APIs Your MIDlet Yellow Pages, train schedules and ticketing, games… UI, HTTP networking... Threads, no Floats… 32-bit RISC, 256K ROM, 256K Flash, 64K RAM

35 CLDC Available Packages r java.lang r java.util r java.io r javax.microedition.io

36 CLDC Classes r Boolean r Byte r Character r Class r Integer r Long r Math r Object r Runnable r Runtime r Short r String r StringBuffer r System r Thread r Throwable r Calendar r Date r Enumeration r Hashtable r Random r Stack r TimeZone r Vector r ByteArrayOutputStream r ByteArrayInputStream r DataOuput r DataInput r DataInputStream r DataOutputStream r InputStream r InputStreamReader r OutputStream r OutputStreamWriter r PrintStream r Reader r Writer java.lang java.util java.io

37 Networking Connection r Based on a framework called the Generic Connection Framework (GCF) r GCF consists of m an interface hierarchy that is extensible m a connection factory, and m uses Standard Uniform Resource Locators (URLs) to indicate the connection types to create e.g. socket:// file:///myResourceFile.res datagram:// sms://

38 MIDP Hardware r Memory (added to CLDC memory) m 128 KB non-volatile for MIDP components m 8 KB non-volatile for application persistent data m 32 KB volatile for KVM r Display m screen 96x54 m display depth 1-bit m pixel shape (aspect ratio) 1:1

39 MIDP Hardware r Input (one or more) m one-handed keyboard (ITU-T phone keypad) m two-handed keyboard (QWERTY keyboard) m or touch screen r Networking m two-way m wireless m possibly intermittent m limited bandwidth

40 MIDP Packages r java.io r java.lang r java.util r javax.microedition.io r javax.microedition.lcdui r javax.microedition.rms r javax.microedition.midlet r javax.microedition.lcdui.game r javax.microedition.media r javax.microedition.media.control r javax.microedition.pki addition in version 2.0 version 1.0

41 MIDP Application Model r An MIDP application is called a MIDlet m similar to the J2SE applet m GUI based r MIDlet suites – for applications that share resources or data

42 MIDP: Application Lifecycle r MIDlets move from state to state in the lifecycle, as indicated m start – acquire resources and start executing m pause – release resources and become quiescent (wait) m destroy – release all resources, destroy threads, and end all activity PauseActiveDestroyed startApp destroyApp pauseApp destroyApp

43 HelloWorldMIDlet.java import javax.microedition.midlet.*; import javax.microedition.lcdui.*; public class HelloWorldMIDlet extends MIDlet implements 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(); }

44 Developing J2ME Applications r Identify the devices r Identify the profiles supported by devices m using the MID profile, the application will target cell phones and pagers r Develop application m install jdk, a package supporting the wireless target (e.g., Sun Wireless Toolkit for CLDC) m debug using a simulator m for deployment, preverify by pre-generating “stack map”

45 Stack map attribute increases the size of a classfile by appro. 5% but substantiall y reduces device mem and CPU usage Deploying: Two-Phase Class File Verification Process

46 Deploying r Generate deployment files: two files Java Application Description file (.jad) Java archive file (.jar) r Upload.jad and.jar to the device or a server where the device can download the application

47 Over-The-Air Application Loading Process Web Page JAM Downloads App User Selects App Advertise App on Web Page Network Transfer Java Application Manager (Name, Version, Size, …) Jar File Descriptor File

48 Summary: J2ME r Scale down a popular programming environment to ease learning r Use virtual machines to mask (some) device heterogeneity r Use versioning to avoid using lowest common denominator

49 Windows.NET Compact Framework r Similar to J2ME r Scales down a popular programming environment to ease learning m the.NET CF is a subset of the full.NET framework with some additions m designed for resource constrained devices m 1,400 classes for.NET CF vs. 8,000 for full m 27 UI controls for.NET CF vs. 52 for full m 1.5 MB for.NET CF vs. 30 MB for full r Uses versioning to avoid using lowest common denominator m pocket PC m pocket PC phone version m smart phone version r Uses virtual machines to mask device heterogeneity m 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 50

Andriod 51

Andriod Features r Linux kernel as foundation r Java based framework (J2SE not J2ME) r Dalvik Virtual machine 52

Application Framework: Key Concepts r Activity m Visible screen r Service m Background services r Content provider m Shared data r Broadcast receivers m Receive and react to broadcast events r Intent m Activating component 53