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<!doctype html public "-//w3c//dtd html 4.0 transitional//en"><html> <head> <title>Lesson: Maté</title> </head> <body bgcolor="#f8f8ff" link="#005BB7" vlink="#005BB7"> <table border=0 hspace=4 cellspacing=2 width="100%" cellpadding=3> <tr bgcolor="#e0e0ff"> <td width="100%"> <font face="tahoma,arial,helvetica"><b><big><big> Maté</big><br> <b>Safe and Rapid Sensor Network Programming</b></big></b> <p> Last updated 22 Mar. 2004 </font> </td></tr> </table> <p> <table border=0 hspace=4 cellspacing=2 width="100%" cellpadding=3> <tr bgcolor="#e0e0ff"> <td width="100%"><nobr> <b> <font face="arial,helvetica">Introduction</font> </b></td> </tr> </table> </p> <p>Maté allows users to program TinyOS networks with short, high level event handler scripts. Users install a virtual machine TinyOS application on motes, and a Java application compiles scripts to the VM bytecodes. These bytecodes run in a sandboxed VM environment, so buggy programs cannot crash a mote. Event handlers have version numbers, and motes automatically install new versions they hear. Once a single copy of a newer program is installed, the network will automatically propagate it to every node.</p> <p>Maté simplifies programming by providing a synchronous interface to TinyOS operations. For example, the <code>send()</code> function blocks until the underlying <code>sendDone</code> event is handled by TinyOS. This makes code much less complex, especially for novice programmers. Currently, Maté programs are written in a simple, BASIC-like scripting language called TinyScript. We are working on making the architecture flexible enough for alternative scripting language options.</p> <p>As the core of Maté is a virtual machine, it also provides a form of execution protection. Unlike TinyOS applications, which have no user/kernel boundary, Maté programs cannot crash a mote or render it unresponsive. Maté catches errors at run time (e.g. accessing an invalid heap variable) and has a mechanism for alerting a user to them (all the LEDs blink and it sends a message), including simple debugging information on the code that caused the error.</p> <p>Maté has an event-based execution model; pieces of code are run in response to events, such as a timer or a packet reception. The presence of blocking operations requires that event handlers be able to run in parallel; the presence of shared variables could make race conditions a significant problem. Maté handles this issue by having handlers implicitly lock all shared resources they use; the set of shared resources used is computed with a full program analysis when code is installed. Therefore, a programmer can write several Maté event handlers that share variables and be sure there will be no race conditions without having to consider the necessary synchronization.</p> <p> <table border=0 hspace=4 cellspacing=2 width="100%" cellpadding=3> <tr bgcolor="#e0e0ff"> <td width="100%"><nobr> <b> <font face="arial,helvetica">Building and Installing Maté</font> </b></td> </tr> </table></p> <p>Maté allows users to build customized virtual machines for specific application deployments. However, it also has two simple example VMs which you can build and use.</p> <p>Maté's code resides in two directories. The first, <code>tools/java/net/tinyos/script</code> is the Java toolchain for building VMs and writing scripts. The second, <code>tos/lib/VM</code>, is the actual VM TinyOS code.</p> <p>The first step to using Maté is to build the Java toolchain. Go to <code>tools/java/net/tinyos/script</code> and type <code>make</code>. This builds the two principal tools, VMBuilder and Scripter, as well as all of their supporting code (parsers, etc.).</p> <p>Once you've built the toolchain, the next step is to build a Maté VM and associated scripting environment. Go to <code>tos/lib/VM/samples</code>. You should see two files: <code>bombilla.vmsf</code> and <code>simple.vmsf</code>. These files describe VMs. Build Bombilla by typing: <center> <table border=0 hspace=4 cellspacing=2 width="80%" cellpadding=3> <tr bgcolor="#e0e0e0"> <td width="100%"> <code> <pre>$ java net.tinyos.script.VMBuilder -nw bombilla.vmsf </pre> </code> </td></tr> </table> </center> You <b>must</b> do this from the <code>samples</code> directory. You should see output similar to this: <center> <table border=0 hspace=4 cellspacing=2 width="80%" cellpadding=3> <tr bgcolor="#e0e0e0"> <td width="100%"> <code> <pre>Creating filesGenerating language-based instructions.Organizing function primitives.Making Config fileMaking constants fileMaking component file164 of 256 opcodes used.Making makefile (haha!) </pre> </code> </td></tr> </table> </center> </p> <p>Running <code>VMBuilder</code> on this file creates an application in <code>tinyos-1.x/apps/Bombilla</code>. There should be four files: <code>Makefile</code>, <code>MateConstants.h</code>, <code>MateTopLevel.nc</code> and <code>vm.vmdf</code>.</p> <p>Go there and type <code>make pc</code>. Running make should create a new directory, <code>vm_specific</code>, which contains several Java classes for the Bombilla VM, as well as build a TOSSIM version of the VM. You can correspondingly <code>make mica2</code> for mica2 nodes. Note that every time you build a Maté executable, <code>make</code> regenerates the Java files. Correspondingly, <code>make reinstall.num</code> can be useful.</p> <p>Build Bombilla for the hardware that you have. Install the VM on a single node, with ID 0 (<code>make reinstall.0</code>). Plug that mote into your serial port. Then, from the Bombilla directory, type <center> <table border=0 hspace=4 cellspacing=2 width="80%" cellpadding=3> <tr bgcolor="#e0e0e0"> <td width="100%"> <code> <pre>$ java net.tinyos.script.Scripter -comm serial </pre> </code> </td></tr> </table> </center> </p> If you aren't using a serial port, or have some specific options you need (e.g., <code>-comm serial@COM2</code> or <code>-comm sf</code>), change the parameter correspondingly.</p> <p>This will load a Scripter interface for Bombilla. It should look something like this:</p> <p> <center><IMG SRC="imgs/bombilla.jpg"><br> <b>The Scripter Interface</b></center> </p> <p>This is the interface for writing scripts to install on a Maté network.</p> <p> <table border=0 hspace=4 cellspacing=2 width="100%" cellpadding=3> <tr bgcolor="#e0e0ff"> <td width="100%"><nobr> <b> <font face="arial,helvetica">The Scripter Interface</font> </b></td> </tr> </table> </p> <p>The Scripter interface is broken into three major parts. We'll step through each of them, one by one.</p> <p>The left panel has two fields, Mote ID and Version Number. In Mote ID you should enter the ID of the mote at the end of the serial port; in this case, it's 0, so you don't need to change anything. You generally do not need to change the Version Number field; the interface will take care of that for you. However, sometimes you need to manually change it. For now, leave it alone.</p> <p> <center><IMG SRC="imgs/bombilla-left.jpg"><br> <b>The Left Scripter Panel</b></center> </p> <p>Below the two fields is a selection for which event handler you which to program. The Bombilla VM has two event handlers: Once and Timer0. The Once event handler runs once, when new code is installed. Timer0 runs periodically at some frequency. By default, it is disabled. Other VMs can handle different events than these, such as packet reception, target detection, or processing requests. Bombilla is a simple one, however, so only has these two.</p> <p>Below the selection is an area called <b>Shared Variables</b>. As a later section shows, scripts can declare variables that are shared across scripts. This area displays all of the shared variables currently in use. For now, it's empty. To the right of this display is the <b>Inject</b> button, and a greyed-out button, which you can ignore. Inject is used to introduce a new program to a network.</p> <p> <center><IMG SRC="imgs/bombilla-center.jpg"><br> <b>The Center Scripter Panel</b></center> </p> <p>The center panel has a single area, <b>Program Text</b>. This is where you write TinyScript code to compile and install in a network.</p> <p> <center><IMG SRC="imgs/bombilla-right.jpg"><br> <b>The Right Scripter Panel</b></center> </p> <p>The right panel has two areas. On top is a list of <b>Primitives</b>. These are functions, beyond general TinyScript operations, that scripts can call. Selecting one of them brings up a brief description in the lower panel.</p> <p>When you quit Scripter, you should always do so through the <b>File</b> menu. Scripter saves some state about the current session to a file, and quitting without using this menu item prevents this from happening.</p> <p> <table border=0 hspace=4 cellspacing=2 width="100%" cellpadding=3> <tr bgcolor="#e0e0ff"> <td width="100%"><nobr> <b> <font face="arial,helvetica">A First Program: CntToLeds</font> </b></td> </tr> </table> </p> <p>Select the <code>Timer0</code> handler in the left panel. Then type this program into the program text area: <center> <table border=0 hspace=4 cellspacing=2 width="80%" cellpadding=3> <tr bgcolor="#e0e0e0"> <td width="100%"> <code> <pre>private counter;counter = counter + 1;call led(counter & 7); </pre> </code> </td></tr> </table> </center> This is CntToLeds in TinyScript; it keeps a private variable <code>counter</code>, which it increments each time it executes. It then calls <code>led()</code> with the low three bits, to display them. Press <b>Inject</b>.</p> <p>In the shell you started Scripter from, you should see output similar to this: <center> <table border=0 hspace=4 cellspacing=2 width="80%" cellpadding=3> <tr bgcolor="#e0e0e0"> <td width="100%"> <code> <pre>Generating assembly.Assembling to instruction set.Sending program: 38 81 00 40 38 87 03 1c 02 Sending 1 chunks (9,28): +Garbage collecting variables </pre> </code> </td></tr> </table> </center> This says that it was able to correctly compile the program to assembly code, translate that assembly to the VM opcodes, then send it. Scripter breaks larger programs up into "chunks," which is sends one by one. In this case, the program is nine bytes long and the chunk size is 28 bytes, so it sent a single chunk. Once the program has been sent, the Scripter checks what variables all of the handlers use to see if any shared variables (more on that later) can be reclaimed (garbage collected).</p> <p>When the Timer0 event fires, Maté will run this code. However, Timer0 doesn't fire when the VM boots. We need to tell the VM to start firing Timer0. We'll do this with the Once handler. We'll need to use one of the Primitives, <code>settimer0</code>. Click on it in the right panel to read its description.</p> <p>Select the Once handler, and type this program:⌨️ 快捷键说明
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