If you're looking for low latency messaging, here's an interesting comparison of some of the more popular MQ products: ZeroMQ, RabbitMQ, ActiveMQ and MSMQ. As the author noted, ZeroMQ is a different beast to the others, as it has a broker-less, peer-to-peer architecture - meaning that it doesn't require a standalone, single-point-of-failure server process.
The benchmark results are startling to say the least: ZeroMQ stands tall over the others, it's like placing the Burj Khalifa next to Big Ben.
However the results are easily debunked. (Debunked is probably the wrong word, as the author does state that ZeroMQ shouldn't really be part of the test). Without doubt ZeroMQ is a quality product, an extremely fast client; but it doesn't provide non-durable queues, meaning it isn't failsafe, and you'll need to provide your own auditing and recovery. An in-memory process is always going to outperform an equivalent process that regularly huffs its data out to disk.
But needs vary, and if you need "very" low-latency messaging (say 10,000 messages/second with latencies under 200ms), a non-broker-based architecture like ZeroMQ or 29West is needed.
There are plenty of other high-performance messaging solutions out there, of course: Kafka, RavenMQ, HornetQ, the Spread Toolkit, 29West (or Informatica Ultra Messaging as it is now) and of course Tibco EMS.
If you enjoy reading about other peoples' travel adventures - or writing about your own - then check out my new website Fingerpress Travel.
As the name suggests, it's the 'sister website' of book publisher Fingerpress. In fact they tie together with a rather nice competition. Anyone can post articles and 'true stories' to Fingerpress Travel; site users then vote for their favourites. After a while - actual time TBD based on how many submissions we receive - we'll pick the top-voted articles/stories and publish them in one or more travel books.
Naturally we'll pay for the articles we publish in the travel books, on a per-word basis plus a free print copy of the book.
All entrants who submit an article of 1000 words or more will also receive a free ebook copy of the first travel guide we publish, so you really can't lose!
Here's an excerpt from a "walking tour" that was posted to the site a couple of days ago:
One of the great things about London is the large number of world-class landmarks that are within reasonably close proximity to one another. This article describes a long walk that I took through the city back in 2008. It's a long enough hike (about 5 miles) that most people wouldn't want to do all of it in a single go, but it can be done in sections, or you can "cheat" and take the tube.
Read more travel guides and stories at Fingerpress Travel.
This "flash fiction" piece (aka "short-short") was published on AntipodeanSF back in August, with the shorter title "Grim Love Bus". It's since moved to their dusty archive room; you can also catch the podcast version (narrated by Mark Tremble); and here's the story in its 500-word entirety:
by Matt Stephens
The doors of the Redhound bus coalesce in Prisca's face, stripping cuticles from the tip of her nose. She peers through the gloop, locates the murky form of the bus driver, and fixes him with her deadliest glare.
"I was right here!" Prisca yells. "What'd you shut the door for?" The driver indicates with his thumb that he can't hear a thing and she should activate her Closed Loop audioconf. Grumpily she twitches her head and repeats the accusation.
"Sorry." He sounds genuine. "Procedures and all that. I have to regulate passenger intake. Give it ten minutes, then I can let you on."
"But you leave for Tau Ceti in ten minutes!"
"I promise, I'll let you on. Meantime, why not switch on your VCR? Let's have some fun while we wait."
She starts in surprise. Are bus drivers really allowed to do that? Even starbound space-pilot bus drivers? Still... she can't piss on this guy. He holds power over her right now. Shrugging, Prisca flutters her eyelids to login to the Virtual Chat Room. Her shoulders hunch and she stands alone, slumped like a solitary zombie.
As part of an occasional series on "cool" IT projects, I wrote this piece on TfL's Countdown II project, for The Register. The project updates the old saying about three buses coming along at once, to "You'll wait 10 minutes and then 3 buses will arrive within 30 seconds of each other":
As winter sets in, commuters in London stand huddled at bus stops, hoping the shelters' electronic signs report an accurate "due" arrival time rather than a crappy guess.
Those lucky enough to have Transport for London's Countdown system of signs installed at their stops can judge by the minutes flickering on the display whether to brave the chill or nip into the warm caff for a coffee.
The problem is, the signs are not at every stop so some passengers are out in the cold figuratively as well as literally. The equipment is also susceptible to vandalism, and the timetable information isn't being pushed to the phone in your pocket.
But TfL plans to change this with the launch of Countdown II, which went live on Monday after three years in the making. ...
jQuery Pocket Reference
by David Flanagan
Published: December 28, 2010
Concise but information-rich: an introduction rather than a reference book.
It seems fitting that for a lightweight library like jQuery, there should be a lightweight manual perched next to your keyboard. And jQuery Pocket Reference does the job perfectly. Its author David Flanagan (of the Java In A Nutshell fame) does a remarkable job of distilling the details into the book's 130 or so pages, while keeping the whole thing readable.
And the paperback's diminutive size has some unseen benefits...
Chapter 7 of Design Driven Testing just went onto the Sparx Community website as a free download. (Sparx are the creators of Enterprise Architect, nowadays the *only* real choice for enterprise analysis and design modeling).
Somewhat uniquely, the book features a real production system as its teaching example. A worldwide interactive hotel mapping (GIS) application, designed with the ICONIX Process, built using Java, Flex, and the ESRI ArcGIS Server mapping software, that we call "Mapplet 2.0", which is in production use on the VResorts.com travel website.
Here's how the chapter is introduced on the Sparx site:
This chapter focuses on Acceptance Testing, and leverages EA's Structured Scenario editor heavily to accomplish something we call "use case thread expansion" where all of the sunny day / rainy day permutations of a use case are expanded out into a complete set of tests.
In test driven approaches to development, unit testing often gets most of the attention. However, unit testing is generally most useful in discovering "errors of Commission" (more poetically, "whoops, I coded that wrong"). Unit testing is of much less help in discovering "errors of Omission" (more poetically, "whoops, I didn't think of that"). In general errors of Omission are much trickier to detect, and there is very little automated support for detecting them. We worked very closely with the development team at Sparx as they developed the "use case thread expander", and it brings a very unique and useful capability to the industry.
As you read this chapter, make sure you don't miss the discussion at the end of the chapter called "And the moral of the story is..." where we describe some actual "errors of Omission" that were caught and fixed before the release of our mapping software using these acceptance testing techniques, and how fixing these errors improved the user experience.
In case you're still undecided about whether to buy a copy of DDT (or like me, if you just like reading free chapters!), Chapter 4 is also available for download. This chapter presents the full ICONIX Process design of the Mapplet project, starting from functional requirements and use cases, all the way down to reverse engineered class diagrams from the final code. One of the unique virtues of using a production example as a teaching example in a book like DDT is that it's possible for readers to look at the use cases in the attached chapter, and then compare them to the released software as deployed on VResorts.com.
My latest article at The Register:
Robert Heinlein was right to be worried. What if there really is a planet of giant, psychic, human-hating bugs out there, getting ready to hurl planet-busting rocks in our general direction? Surely we would want to know?
Luckily, big science projects such as the Large Synoptic Survey Telescope (LSST), which (when it's fully operational in 2016) will photograph the entire night sky repeatedly for 10 years, will be able to spot such genocidal asteroids - although asteroid-spotting is just one small part of the LSST's overall mission.
Two years ago we spoke to Jeff Kantor, LSST data management project manager, who described the project as "a proposed ground-based 6.7 meter effective diameter (8.4 meter primary mirror), 10 square-degree-field telescope that will provide digital imaging of faint astronomical objects across the entire sky, night after night."
I caught up with Jeff again a couple of weeks ago, and asked him how this highly ambitious project is progressing.
They now have a prototype system of about 200,000 lines of C++ and Python representing most of the capability needed to run an astronomical survey of the magnitude typically done today. Next, they have to scale this up to support LSST volumes. According to Jeff: "We hope to have all of that functioning at about 20 per cent of LSST scale of the end of our R&D phase. We then have six years of construction and commissioning to 'bullet-proof' and improve it, and to test it out with the real telescope and camera."
Read the full article here.
Here's my latest at The Register - some thoughts based on my recent trip to the Frankfurt Book Fair:
If some of the speakers at this year's Frankfurt Book Fair are to be believed, your life — or at least the part of it that involves snuggling up in bed with a good book and mug of hot cocoa — is about to be turned upside down.
Sure, we've heard plenty on books going electronic, but the coverage mostly focuses on the devices — Kindles, iPads, et al. — rather than the books themselves.
I've written a number of books on software development, and recently began my own publishing company, Fingerpress. I therefore approached this event from the perspective of an upstart book publisher trying to figure out how our published works should fit into the e-publishing space.
I expected the answer to be a bewildering mix of grey areas, but surprisingly — despite the diversity on offer — the answer turned out to be quite clear-cut.
Der Frankfurter Buchmesse 2010's crowded halls feature several so-called technology Hot Spots. The Devices Hot Spot is oddly named because it isn't about devices. Instead it features advances in content creation and delivery — that murky zone in between the device and the customer. One company inhabiting this area is exhibitor Stilo, which specialize in converting content into XML and EPUB formats. Smashwords, which wasn't at the show, converts to a much broader range of platforms for free — provided you use their distribution service, of course.
The Mobile Hot Spot was exactly that, while the Information Management Hot Spot supposedly bought together "the latest developments in workflow processes, content management systems, multimedia integration and advanced content delivery platforms."
There were also Hot Spots for publishing services, literature, special interest (top shelf, sir?), and education.
The predominant message behind almost all of the tech exhibitors at each Hot Spot was this: e-books are here, they're cool, and we should all be using them. Whether that's actually true or not is a different matter.
. . .
The problem is that books — novels especially — are entrenched in our habits and expectations. People love a good novel, and that's unlikely to change. They don't want the formula to be messed with too much. And as for fragmentation? It's always been easier to print a leaflet than a novel, but novels still sell by the million, whereas "short-shorts" don't.
What is changing, and rapidly, is the way that books are delivered to us, along with the medium the words are displayed on. From the Apple iBookstore to Kindle to Kobo, it's never been easier to buy a book and be reading it a few seconds later. And while the device is where the excitement is, the real war is to potentially own the e-publishing "middle tier" — the site that readers go to in order to buy their books.
It's finally done, and available to buy on Amazon!
This news item was just posted on the Sparx Systems website:
The groundbreaking book Design Driven Testing brings sanity back to the software development process by flipping around the concept of Test Driven Development (TDD)—restoring the concept of using testing to verify a design instead of pretending that unit tests are a replacement for design. Anyone who feels that TDD is “Too Damn Difficult” will appreciate this book. Design Driven Testing shows that, by combining a forward-thinking development process with cutting-edge automation, testing can be a finely targeted, business-driven, rewarding effort. In other words, you’ll learn how to test smarter, not harder.
Design Driven Testing should appeal to developers, project managers, testers, business analysts, architects… in fact anyone who builds software that needs to be tested. While equally applicable on both large and small projects, Design Driven Testing is especially helpful to those developers who need to verify their software against formal requirements. Such developers will benefit greatly from the rational and disciplined approach espoused by the authors.