This e-book includes a summary of sustainable HVAC developments, in particular of heat pumps and refrigerant changes to address climate change.

To meet the ambitious environmental goals being proposed at all levels of government, residential air-to-water heat pumps are emerging as a transformative solution to lower carbon emissions, enhance energy efficiency, and reduce utility bills.

Variable-speed heat pumps, which dominate the heat pump market in many countries, are getting more attention in the U.S. The NEWS asked several manufacturers about the benefits of the technology.

Due to a lack of training, time constraints, and numerous other reasons, many HVAC contracting companies are not performing combustion testing, potentially compromising customers’ safety.

If contractors don’t have a plan in place to handle red tag furnace second opinions, they can expect some mistakes.

A homeowner in Pickering, Ontario works with an experienced HVAC pro to improve comfort, efficiency, and energy savings with a high-efficiency hydronic forced-air furnace upgrade.

Posted by CISA on Mar 21

Posted by CISA on Mar 23

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.

Eric Evans is the author of the well known Domain-Driven Design book. In his day job he works as a consultant and coach for his own company, Domain Language. In this interview, Eric talks about the essential building blocks of domain-driven design as well as about a set of best practices on how to address complex projects. In a third part, he elaborates on the relationship of domain-driven design and MDSD/MDA.

In this Episode we have the pleasure of talking with Gregor Kiczales. Gregor is one of the fathers of aspect-oriented programming (AOP). Today he is a professor of computer science at the University of British Columbia. Back in his days at Xerox Parc, he and a number of other people worked on the early forms of AOP as well as on some of its forerunners, such as meta object protocols. In this interview, we talk about a number of interesting topics, such as the history of AOP, the relationship of AO to interceptors, the industry acceptance of AOP, early aspects (i.e. using AO in development phased before implementation) as well as adoption strategies for AOP.

In this Episode we talk to Ted Neward. Since Ted is active in the .NET and Java universes, we started out by discussing some of the differences between the two platforms. The main discussion, however, focussed on new features in the C# 3.0 language. These include LINQ (language-integrated query). A very interesting discussion about extension methods, lamda expression, typing (dynamic, duck, compiler) and other language "tricks" follows. We also visited the topic of language development on the .NET and Java platforms in general, also looking at topics such as concurrency and the Scala language.

In this Episode, we talk to Michael Stal, a Senior Principal Engineer at Siemens Corporate Technology, POSA 1 and 2 Co-Author and Editor of the german JavaSpetrum magazine. Since Michael's core focus is middlware, much of our discussion centered around that topic. Webservices and SOA, of course, have also been covered. Other topics include Java vs. .NET as well as Patterns.

In this Episode, Arno, Bernd and Markus interview Jutta Eckstein. Jutta is a pioneer and expert on using Agile software development, specifically in larger teams. In the interview we talk about the agile manifesto, the role of personal relationships and trust in software projects, differences between agility in the small and in the large, as well as offshoring.

SOA (Service Oriented Architecture) appears to be just another hype - after all we have been building distributed systems for quite a while now. But the real value of SOA is non-technical. In this episode Eberhard and Markus discuss the advantages and disadvantages, what SOA actually is and how it compares to other approaches that have been tried out before.

In this, as well as in the next episode Eberhard and Markus continue their discussion about SOA (the episode got too long, so we had to split it into two ... SOA 2a and SOA 2b). In this episode, we talk about the various perspectives on SOA (CBD, EAI, BPM), about fundamental requirements towards an SOA, and we discuss the role of models in defining sustainable architectures. We also discuss how a programming model based on the described approach typically looks like. We then discuss a number of issues any large-scale SOA faces (and for which the SOA paradigm does not really provide an out-of-the-box solution: In this episode we discuss data type ownership and (weak) typing of data types.

This is the second snippet of the SOA 2 double-episode. Eberhard and Markus continue the discussion with the issue of service reuse and a couple of development process issues. We also look at the duality between infrastructure development and application development in the context of an SOA. We then discuss the great spaghetti misunderstanding :-). We conclude this episode with a look at how to integrate BPM into the conceptual SOA framework we've built up to now, and we'll also briefly skim over a number of technologies related to SOA. Note that this episode, as well as the last one, is based on a set of slides; these can be downloaded from here. This episode covers slides 39 through 74.

This episode is an interview with Guy L. Steele Jr.. Guy is a Sun Fellow and heads the Programming Language Research Group within Sun, and a generally well known "programming language guy" (see here for details). We briefly talk about Lisp and the resurgence of dynamic languages before we delve into the main topic, the Fortress programming language he is working on. Fortress is a language intended to replace Fortran as a scientific computing language. We talk about how mathematical notations, syntax extensio and built-in support for parallelism are crucial properties of such a language. We then briefly talk about potentials for compiler optimization before taking a closer look at the type system (static typing, type inference), traits and contract specification as well as first-class support for hierarchical components. We conclude the discussion with a look at automatic partitioning and distribuion of concurrent algorithms and a brief look at the future roadmap for the Fortress language.

Designers, programmers, engineers, we must all return to programming! Very few programmers tend to see their (sometimes rather general) difficulties as the core of the subject and as a result there is a widely held consensus as to what programming is really about. If these notes prove to be a source of recognition or to give you the appreciation that we have simply written down what you already know about the programmer's trade, some of our goals will have been reached.

This episode is an interview with Steve Vinoski. Steve works as the Chief Engineer for IONA. He's what you'd call a middleware guru, he was for example deeply involved with CORBA. So, this interview centers mainly around middleware. We begin by talking about his own history wrt. middleare and ORBs and how ORBs evolved over time. We then talked about whether coarse-grained, stateless components might be a better abstraction for distributed systems than "objects". We then covered the future of CORBA, it's use in ethe embedded space as well as the practical relevance of the POSA patterns when building ORBs. Then we switched topics and addressed the role of web services as a "middleware middleware" and the maturity of WS-* specifications. We then looked at what Steve is working on these days, which is e.g. the Advanced Message Queueing Protocol (AMQP) as well as dynamic languages. We concluded the interwiew with his view on SOA.

This episode is an interview with Werner Vogels, the CTO of amazon.com. We first talked about what scalability is, and which aspects there are to scalability. We then took a brief look at the technologies used at amazon, specifically, the middleware systems and the issue of vendor lock-in. Web services, and the role of SOA was the next topic. Then we covered what a service actually is add Werner explained the term "pizza teams". Testing and Deployment was the next topic followed by a look at architectural characteristics of scalable systems, the value of simplicity and the CAP theorem. We concluded the discussion with a brief look at the future of distributed systems

In this episode, Gregor Hohpe gives us a great introduction to enterprise messaging based on his EAI Patterns book. Before we started discusssing the patterns in his book, we characterized messaging and talked about the various interaction styles. We also contrasted the messaging architectural style with an RPC based approach. We then took a look at the relationship to SOA, the role of contracts and the orchestration-vs-choreography discussion. We briefly discussed the nature of pattern languages before we then went through the different section in the book. There are six main sections: channel, message, routing, transfomation, endpoint as well as management and monitoring. We discussed the core patterns for each of these sections. This should give listeners a good high-level view of message-based systems. We concluded the discussion by looking at the critical importance of systems management and monitoring.

This is another episode on concurrency. We talk to two experts in the field, Brian Goetz and David Holmes about aspects of concurrency we hadn't really covered before. We start out by discussing liveness and safety and then continue to talk about synchronizers (latches, barriers, semaphores) as well as the importance of agreeing on protocols when developing concurrent applications. We then talked about thread confinement as a way of building thread-safe programs, as well as using functional programming and immutable data. The next set of topics covers various ways of how compilers can optimize the performance wrt. to concurrency, talking about techniques such as escape analysis as well as lock elision and coarsening. We then covered how to test concurrent programs and the consequences of the Java memory model on concurrency. We then went on to look at some more advanced topics, namely, lock-free programming and atomic variables. We also briefly discussed the idea of transactional memory. Finally, we looked at how better language support - specifically, a more declarative style of concurrent programming as e.g. in the Fortress language - can aid in improving the quality of concurrent programs.

In this Episode we are happy to talk to Grady Booch. We started off by discussing his Architecture Handbook, how it came into being, the progress, and how it will look like once it's finished. In this context we also looked at the issue of how to distinguish architecture from design. We then asked him about how "professional" software architecture is these days, as well as about the ubiquity of software product lines in industry. The next couple of minutes looked at the question of whether software development is an engineering discipline, craftsmanship or an art form, and we discussed the key qualifications of software developers. Grady then elaborated on the problems of developing in large teams as well as the potential limits of complexity we can tackle with software.

We then got back to a more technical discussion, where we looked at model-driven development, DSLs, etc. and the role of the UML in that context. Next was a discussion about scripting languages, and the current trend towards new languages. We then looked at component marketplaces and other forms of reuse, as well as the importance of OO these days and the relevance of AO. We concluded with a (small) outlook to the future.

In this Episode we discuss software architecture evaluation with Dragos Manolescu, an architect at Microsoft's patterns & practices group.

We start off the discussion by trying to define what software architecture evaluation is and when and you want to evaluate an architecture in the system's lifecycle. We then make sure evaluators set the expectations for the evaluation process right - it is important to understand that architecture evaluation is typically not primarily a review of the technology decisions made for the architecture.

We then discuss the kinds of notations that are useful for describing architectures, and which of these are especially helpful for the evaluator. Next we look at the core of the architecture evaluation task, namely, the integration of the various stakeholders and their views. We also discuss real reviews from reviews that are staged "for show" only.

Next in the discussion is a brief look at the tools you can use for architecture evaluation, as well as a closer look at the various methods for achitecture evalualtion proposed by the Software Engineering Institute (SEI). We conclude the discussion by outlining how architecture evaluation fits into an agile development process.

... and finally, we briefly plug the PLOPD5 book, on which Dragos, Markus and James Noble have been working recently :-)

This episode is an interview with Frank Buschmann, one of the pioneers of the pattern movement in Europe. Michael and Frank discuss how it all began: the first conferences on patterns and the first publications by the Gang-of-Four and the POSA 1 team. Frank then elaborates on the new volumes in the Pattern-Oriented Software Architecture book series - POSA 4 and POSA 5 - and gives some examples from the books. The episode concludes with a general discussion on software design and architecture, and best practices on software development.

This episode is a conversation with Erich Gamma. We covered the four things he is known for in chronological order. We started with design patterns and the Gang-of-Four book of which he is the lead author. We then looked at JUnit, the testing framework he coauthored with Kent Beck and how it introduced unit testing to the masses. The next topic is obviously Eclipse, where Erich and his lab in Zürich is responsible for the Java Development Tooling. We also briefly discussed The Eclipse Way, the (obviously) successful process the Eclipse team uses for developing Eclipse itself. Finally, we're looking at Erich's current endeavour, the Jazz project. Jazz is a technology for collaborative software development.

In this Episode we're talking about Web Services with IBM's Olaf Zimmermann. We mainly focus on the WS-* stack. We also discuss a couple of SOA foundations and architectural decisions that need to be taken when building an SOA using Web Serivces. We also briefly mention the REST vs. WS-* debate.

This episode is an interview with Dave Thomas (OTI Dave or Smalltalk Dave, not PragDave). We started our discussion with a look at the (non-)success of objects and components. We then discussed some history behine Eclipse and Dave's role in OTI. We then compared Smalltalk and Ruby and looked at the promises of small and powerful languages such as Lisp. We also discussed the role of (static) type systems and the role of tool support for languages. We then switched gears and looked at what is necessary to scale agile development to the level of large organizations and how techniques from lean production and manufacturing as well as product management can play an important role. In the last part of the interview we looked at the state of research today, and especially the relationship between industry and academia in this area. We concluded the interview with Dave's opinion on what it takes to be a good developer.

In this episode, Markus talks to Rebecca Wirfs-Brock on what she has learned from architecture reviews. This is a very complement to the earlier episode on architecture evaluation.

This episode is the long-awaited (and much requested) interview with Krzysztof Czarnecki, the author, together with Ulrich Eisenecker, of the book Generative Programming. In the interview we discussed the state of generative programming today and related it to model-driven development and DSLs. We then talked a little bit about product lines in general. We then discussed his current field of research, which currently focusses on framework-specific modeling languages and non-trivial roundtrip engineering.

In this episode we have the pleasure of talking to Anders Hejlsberg, Chief Language Strategist at Microsoft. We started by discussing his more distant past, namely, his involvement with Turbo Pascal and Borland's Delphi. We then looked at the influences Delphi had on C# and how C# evolved from Delphi. In the next section we discussed a couple of general language design issues, among them components and checked vs. unchecked exceptions. Next, we discussed interesting issues about languages of the future, static vs. dynamic typing, functional programming, meta programming as well as the importance of good support for concurrency. We concluded the discussion by looking at the interplay between languages and IDEs.

In this episode we're talking to Eelco Visser about parsing text. We start at the basics - what is parsing? - covering classic tools such as Yacc and classic parsing approaches such as LALR before examining how more recent approaches such as scannerless parsing can make parsing easier and enable previously impractical use cases.

This is a discussion with Janos Sztipanovits about Cyber Physical Systems and how DSLs are used to approach some of the challenges in that domain. Specifically, in the second part we talk about formalizing DSL semantics.

This episode is a discussion about code and metrics visualization with Michele Lanza. Michele invented the Code Cities idea about which he talks in this episode.

In this episode, Dirk talks with David Frankel, resident Metamodeller and MDA expert at SAP Labs LLC, SAP's subsidiary in the Silicon Valley. Dave's extensive experience provides a big picture, from the early days of CORBA all the way to current issues that are bugging most enterprise architects' work with MDA.

This episode is a discussion with Jim Des Rivieres about APIs: How to design good APIs, the role of the documentation/specification in APIs, API evolution and other relevant topics.

In this episode we talk with Doug Simon from Sun Microsystems Laboratories about the Maxine Research VM, a so-called meta-circular virtual machine. Maxine is a JVM that is written itself in Java, but aims at taking JVM development to the next level while using highly integrated Java IDEs as development environments and running and debugging the VM itself directly from the Inspector, an IDE-like tool specialized for the Maxine VM. During the episode we talk about the basic ideas behind Maxine, what exactly "meta-circular" means and what makes it interesting and promising to build a Java VM in Java. We talk about the relationship to Sun's current production JVM (HotSpot) and about ideas and directions for the future of Maxine.

This episode is part of our series on agile software development. We talk with David Anderson about Kanban, an agile software development method that is quite different from most of the other agile methods out there. We discuss the basic ideas behind Kanban, the differences between Kanban and Scrum and when and why projects can benefit from using Kanban. This episode is done in cooperation with the German magazine ObjektSpektrum (thanks for sharing this interview with us).

This time we have John Wiegand on the mic for an episode on architectures and agile software development. We talk about the role of architectures in an agile world and why architectures change and need to change over time. We discuss the characteristics of those living architectures, using the Eclipse and the Jazz projects as examples, and the surrounding development methods for such environments.

Micro services is an emerging trend in software architecture that focuses on small, lightweight applications as a means to avoid large, unmaintainable, monolithic systems. This approach allows for individual technology stacks for each component and more resilient systems. Micro services uses well-known communication schemes such as REST but also require new technologies for the implementation. […]

Johannes Thönes talks to James Lewis, principal consultant at ThoughtWorks, about microservices. They discuss microservices’ recent popularity, architectural styles, deployment, size, technical decisions, and consumer-driven contracts. They also compare microservices to service-oriented architecture and wrap up the episode by talking about key figures in the microservice community and standing on the shoulders of giants. Recording […]

Josh Long talks to Activiti cofounder Joram Barrez about the wide world of (open source) workflow engines, the Activiti BPMN2 engine, and what workflow implies when you’re building process-driven applications and services. Joram was originally a contributor to the jBPM project with jBPM founder Tom Baeyens at Red Hat. He cofounded Activiti in 2010 at […]

David Heinemeier Hansson, creator of the Ruby on Rails framework and a partner at the software development company Basecamp, talks to Stefan Tilkov about the state of Ruby on Rails and its suitability for long-term development. He addresses some of its common criticisms, such as perceived usefulness for only simple problems, claimed lack of scalability, and increasing complexity. David also talks about the downsides of building JavaScript-centric, “sophisticated” web UIs, and why he prefers well-structured, “majestic” monoliths to microservices.

Charles Anderson talks with James Phillips about service discovery and Consul, an open-source service discovery tool. The discussion begins by defining what service discovery is, what data is stored in a service discovery tool, and some scenarios in which it’s used. Then they dive into some details about the components of a service discovery tool and how reliability is achieved as a distributed system. Finally, James discusses Consul, the functions it provides, and how to integrate it with existing applications, even if they use configuration files instead of a service discovery tool.

Jeff Meyerson talks to Idit Levine about Unikernels and unik, a project for compiling unikernels. The Linux kernel contains features that may be unnecessary to many application developers--particularly if those developers are deploying to the cloud. Unikernels allow programmers to specify the minimum features of an operating system we need to deploy our applications. Topics include the the Linux kernel, requirements for a cloud operating system, and how unikernels compare to Docker containers.

Kishore Bhatia talks with Travis Kimmel about Engineering Impact: In the age of data-driven decision making, how does one go about measuring, communicating, and improving engineering productivity? We’ll learn from Travis’ experience building data analytics tools in this space, with insights and best practices for engineering teams and business stakeholders for measuring value and productivity.

Nate Black interviews Glynn Bird on using open source to develop your career or get a job, and how maximize productivity and learning. We discuss how to get your pull request accepted, how to make your own project successful, and how to survive updates.