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Java for embedded systems Felix G. Hamza-Lup. Outline Embedded systems characteristicsEmbedded...

Date post:23-Dec-2015
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  • Slide 1
  • Java for embedded systems Felix G. Hamza-Lup
  • Slide 2
  • Outline Embedded systems characteristicsEmbedded systems characteristics Application domains Java characteristics Java in embedded systems Future trends References
  • Slide 3
  • Embedded systems Real-Time systems Timing constrains play a critical role in their design and implementation. Have dedicated functionality i.e. designed strictly for a specific set of tasks Incorporate relatively low-speed microprocessors and may have a limited amount of memory.
  • Slide 4
  • Embedded systems - Inputs Random Short-lived external signals Processor must interrupt whatever else it is doing to capture the data, or it will be lost => => embedded programs are organized as a set of individual, but cooperating threads of execution.
  • Slide 5
  • Hardware for embedded applications Most embedded systems are housed within a highly-constrained box. lack of space excessive vibration => => embedded applications will be structured as a small section of initialization code that starts the programs from a ROM disk
  • Slide 6
  • Outline Embedded systems characteristics Application domainsApplication domains Java characteristics Java in embedded systems Future trends References
  • Slide 7
  • Embedded systems applic. domains Machine and process control Medical instruments Data acquisition Network components: routers and switches
  • Slide 8
  • Less constraints Telephony: mobile phones, pagers PDAs
  • Slide 9
  • Outline Embedded systems characteristics Application domains Java characteristicsJava characteristics Java in embedded systems Future trends References
  • Slide 10
  • Characteristics Portability platform independence Software reuse OO Simplicity easy to learn Safety and security -Java TM Authentication and Authorization Service (JAAS) -Java TM Cryptography Extension (JCE) -Secure Socket Extension (JSSE)
  • Slide 11
  • Some key characteristics The key characteristics of Java that make it attractive as a specification language for embedded systems are: Built in multithreading and synchronization Lack of pointer arithmetic Automatic memory management
  • Slide 12
  • Outline Embedded systems characteristics Application domains Java characteristics Java in embedded systemsJava in embedded systems Future trends References
  • Slide 13
  • Technical challenges for embedded environment
  • Slide 14
  • Problems with Desktop Java Too big: JVM + JIT (just-in-time) compiler+libraries 16 MB Too slow: 5 x slower than C code No notion of address: most often hardware is accessed referring to a specific address Security, portability, dynamic behavior not needed in embedded systems
  • Slide 15
  • Problems with Desktop Java Java Garbage Collector - collect unused memory JCG dangerous in embedded systems stop-the- world effect Memory allocation is not fast enough and not predictable
  • Slide 16
  • Java embedded: alternatives Special purpose JVM and core libraries JVM with JIT compiler Compiled JAVA (instead of interpreted)
  • Slide 17
  • Special purpose JVM and Frameworks Suns PersonalJava Sun's EmbeddedJava JIT compiler J2MicroEdition JADEs LEAP
  • Slide 18
  • PersonalJava Re-implements the full set of Java APIs defined by the Java application environment Fits into smaller devices with more limited memory configurations
  • Slide 19
  • EmbeddedJava - Goals Standardize software development for embedded devices Integrate a compact EmbeddedJava application environment directly into new devices Small adjustable memory footprint
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