Software Engineering Radio

Recording Venue:
Guest(s): Peter Kriens
BJ Hargrave

Host(s): Martin Bernd
This episode is about OSGi, the dynamic module system for Java. Our guests are Peter Kriens (OSGI’s Technical Director) and BJ Hargrave (OSGI’s CTO). We’ll discuss what OSGi is all about and why and in which contexts it is useful. Additionally we are having a look at the different layers of OSGI and where and how they are used. Other questions discussed are: What means dynamicity in an OSGI environment? Where is OSGI used? What’s the future of OSGI? How does OSGI interact with existing middleware solutions? How can I run several versions of the same JAR at the same time? Where are OSGI’s problems?

Links:

• Part 2 of a webinar series on OSGi – Installing some bundles
• Part 1 of a webinar series on OSGi – Running OSGi
• Peters blog
• Tutorials for OSGi
• Peter’s tools
• Run OSGi inside an App-Server
• The Spring Framework can run on OSGi as well
• The free OSGi Implementation Knopflerfish
• The free OSGi Implementation Apache Felix
• The free OSGi Implementation Equinox
• The Website of the OSGi Alliance
• The OSGi Specification
• A repository of all kinds of different osgi modules
• JSR 291: Dynamic Component Support for Java SE
• Part 3 of a webinar series on OSGi – Running some games
• Part 4 of a webinar series on OSGi – Installing a php wiki on top of OSGi

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Recording Venue: OOP 2007
Guest(s): Charles Weir
James Noble

Host(s): Markus
In this Episode we’re discussing patterns for small memory software with the authors of the like-named book Charles Weir and James Noble. We look at various aspects of the small memory problem: How can you manage memory use across a whole system? What can you do when you have run out of primary storage? How can you fit a quart of data into a pint pot of memory? How can you reduce the memory needed for your data? How do you allocate memory to store your data structures? Answers to all those questions are provided in this Episode, and of course in their book.

Links:

• Symbian Developer Homepage
• SonyEricsson Developer Homepage
• Windows Mobile Developer Homepage
• Book: Garbage Collection and Memory Management
• Book Homepage
• Book at Amazon
• Penrillian – Charles’ company

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Recording Venue:
Guest(s): Robert S. Hanmer

Host(s): Markus
This is the second part of the discussion on fault tolerance with Bob Hanmer (if you didn’t listen to Episode 77, which contains part one, please go back and listen now; this episode builds on that previous one!)

We start by discussing a set of error detection patterns. Among are the well-known approaches such as checksums and voting. We then look at error recovery patterns, including restart, rollback or roll forward. The next section looks
at error mitigation patterns, which include shedding load and doing fresh work before stale. The last patterns section then looks at fault treatment patterns.

We conclude the episode with a small discussion about how to design systems using (these and other) patterns, and with some thoughts on why actually wrote the book.

Links:

• “Dependability and Its Threats: A Taxonomy” by Algirdas Avizienis, Jean-Claude Laprie and Brian Randell
• A NASA tutorial on Software Fault Tolerance
• Book Bob’s Book at Amazon
• Telecom I/O Patterns
• Bob’s Book at Wiley
• “Computers in Spaceflight: The NASA Experience” by James E. Tomayko

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Recording Venue:
Guest(s): Robert S. Hanmer

Host(s): Markus
In this Episode we discuss fault tolerance based on the new book by Bob Hanmer. This is the actually the first part of the discussion, the remainder will be published in the next episode of SE Radio.

We start by discussing some of the context for fault tolerant systems and the imperfect world assumption. We then discuss a number of terms we will need when discussing the fault tolerance patterns. We then discuss the fault tolerance mindset and connect fault tolerance to a number of related subject areas, such as software quality. We then discuss the shared context for the patterns that follow, among them the important observation that fault tolerance does not come for free!

Finally we provide an overview over the different sections covered in the book and start the detailed discussion of the patterns by looking at the Architectural Patterns section.

The next episode will discuss the remaining patterns in the book.

Links:

• Bob’s Book at Wiley
• Book Bob’s Book at Amazon
• A NASA tutorial on Software Fault Tolerance
• “Dependability and Its Threats: A Taxonomy” by Algirdas Avizienis, Jean-Claude Laprie and Brian Randell
• “Computers in Spaceflight: The NASA Experience” by James E. Tomayko
• Telecom I/O Patterns

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Recording Venue:
Guest(s): Bruce Powel
Douglass

Host(s): Markus
This episode is a conversation with Bruce Powel Douglass on real time systems. We started by discussing what real time software is, and explored the difference between hard and soft real time. We then looked at different scheduling strategies, and the meaning of terms like urgency and importance in the context of scheduling. Next was a discussion of typical architectural styles for real time systems and how architectures are described in this context. This led us to a discussion about the importance of modeling, formalisms and languages as well as the role of automatic code generation from those models. We then looked at how to model QoS aspects and the role of SysML for modeling real time systems. We then had a brief look at which programming languages are used these days for real time systems and the role of static analysis to determine various properties of those programs in advance. The last part of the discussion focused on some best practices for building real time systems, the challenges in distributed real time systems and how real time systems can be tested effectively.

Links:

• Harmony Process
• UML Profile for Schedulability, Performance, and Time, v1.1
• Rhapsody Tool Suite
• UML Profile for DODAF/MODAF (UPDM)
• Book: Real Time UML Workshop for Embedded Systems
• Book: Real-Time UML
• Book: Real-Time Design Patterns
• Book: Doing Hard Time
• SDL

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Recording Venue:
Guest(s):
Host(s): Michael Markus
Recording Venue:
Guest(s):
Host(s): Michael Markus
This episode is an introduction to embedded system. It is an introduction in the sense that we cover many topics very briefly: upcoming episodes will provides details for many of these topics.
We start by discussing what an embedded system is an what the important characteristics are. Among them is limited resources, concurrency, real time and hardware integration. We also discuss the range of embedded systems from small mirocontrollers to mobile phones to distributed real time embedded systems. We also cover the different business case for embedded systems (per unit cost) and some non-trivial developmental aspects (cross compilation debugging, heisenbugs).
We close the episode by discussing some important architectural styles (time triggered, event-based, microkernels, state machines) as well as tools of the trade: languages, operating systems and middleware.

Links:

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Recording Venue: OOPSLA 2006
Guest(s): Steffen Schaefer, IBM
Host(s): Markus
In this episode we discuss sensor networks with our guest Steffen Schaefer, who is the Technical Thought Leader for Sensors & Actuator
Solutions at IBM. The discussion resolves around the TREC device, which can be mounted on containers to track them on their journey over seas, railway tracks and roads. The TREC is a small embedded device developed by Steffen’s employer, IBM, that has various sensors and communications channels.

In the episode we first talked about container transport in general, and then looked at how the TREC device works – specifically, it’s hardware, software and power management. We then looked at the necessary backend infrastructure. The main part of the discussion covered the communication between the device and the backend, using technologies such as Zigby, GSM and satellite communications. We also looked at the middleware infrastructures used, such as the MQtt messaging tool.

We closed the episode with a little discussion of the “Internet of Things” and some discussion about embedded software devleopment in general. Note that SE Radio will feature more embedded topics in the future – an introduction to embedded development will be put online soon.

Links:

• Sun Spots – small wireless Java programmable devices from Sun
• Sensor Network solutions from IBM
• Information on intelligent utility networks
• flash demo on How the EPC Network works
• epcglobalinc.org – cross-industry RFID standards
• rfidjournal.com – great source for any kind of information regarding RFID
• interesting workshop papers from OOPSLA06 workshop on Building Software for Sensor Networks. The paper ‘Secure Trade Lane: A Sensor Network Solution for more predictable and more secure container shipments’ contains details on technology and architecture
• information on a pilot project IBM did on tracking containers stuffed with Heineken beer
• MQ Telemetry Transport – Messaging infrastructure for mobile and embedded devices
• Zigbee Alliance – information on the Zigbee standard

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Recording Venue:
Guest(s): Doug Schmidt

Host(s): Markus
In this episode we talk with Doug Schmidt. Doug is a professor of computer science at Vanderbilt University and a well-respected authority in the fields of middleware, patterns and model-driven development. In this interview we talk about these topics in the context of distributed, realtime embedded (DRE) systems.

Links:

• POSA 2 Book
• OMG Data Distribuion Service
• CORBA
• TAO, The ACE ORB
• OMG MIC PSIG
• Doug’s Web Site
• Vanderbilt ISIS
• GME Tool

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