I am using DropBox quite a bit to move files around between various machines (nothing confidential, just stuff that I need to move around and that is a tad on the large side). Today, I hit a very issue where I saved screenshots from a Ubuntu machine and waited for them to show up on a Windows machine. And they never did. Confused, I went to the web interface, and the files were indeed in place there. I could download it from the web interface without an issue. Weird. Other files did sync in the meantime, so just what was going on?
There is a new post at my Wind River blog, about how I helped a colleague resolve a real problem using the preview version of the new Helix Lab Cloud system. The Lab Cloud right now is basically Simics behind a simplified web user interface, exposing the checkpointing and record-replay facilities in a very clear way. You can also share your sessions for live interactions with other people, which is truly cool.
On June 30, Wind River (my job) released Simics 5, the latest version of Simics. I have been working with Simics since 2002 now, and the tool is still improving, adding new features, and adopting the current world. The announcement blog post provides an overview of the features of the new release, and we will be doing some additional in-depth posts later on.
While I was on vacation, Wind River published a blog post I wrote about the new multicore accelerator feature of Simics 5. The post has some details on what we did, and some of the things we learnt about simulation performance.
I followed-up on my visit to the Bovington Tank Museum in the UK with a visit to the Swedish equivalent, Arsenalen in Strängnäs. It is about 100 km from Stockholm, and thus less far off than the UK variant. Arsenalen is strictly speaking a “vehicle” museum, not just a tank museum, even though a majority of the vehicles on display are indeed tanks or at least armored vehicles.
Last week, I visited the rather wonderful tank museum (http://www.tankmuseum.org/home) at Bovington in England, UK. Fascinating, and I am happy to have seem so many legendary machines for real.
Today, I visited the Portsmouth Historic Dockyard in Portsmouth, UK, together with my kids. Somewhat surprisingly maybe, the kids mostly loved it and I got to see and learn a lot of interesting history. I found it particularly usful to compare the three main ships on display: the 1510 Mary Rose, the 1765 HMS Victory, and the 1860 HMS Warrior. They show both the development and continuity of the Royal Navy over a very long period of time.
I have read a few news items and blog posts recently about how various types of software running on top of virtual machines and emulators have managed to either break the emulators or at least detect their presence and self-destruct. This is a fascinating topic, as it touches on the deep principles of computing: just because a piece of software can be Turing-equivalent to a piece of hardware does not mean that software that goes looking for the differences won’t find any or won’t be able to behave differently on a simulator and on the real thing.
There is a new post at my Wind River blog, about the Simics Agent feature that we included in Simics last year. Took a while to get a blog out, as I had so many other things to write about. It was also nice to get a video demo out to accompany the post. The most interesting part about the Simics Agent to me is how much more convenient it is to script a target with an agent on the inside. Too bad that also changes the target software stack a bit — but I do think that that is OK most of the time. As always, the solution has to be designed with the end goal in mind, and there is no absolute right or wrong here. Read the blog post for more details!
I just got hit by a strange behavior in Microsoft word: the comment and format change “balloons” that pop up next to the text when using change tracking and viewing changes started to overflow their allocated balloons. The font used look very funny too. The issue was that a document contained a format specification for these balloons that used a font not present on my system, which in turn caused Word to use something like Courier to display it. Which did not look nice. However, it was easy to solve.
In a dusty bookshelf at work I found an ancient tome of wisdom, long abandoned by its previous owner. I was pointed to it by a fellow explorer of the dark arts of computer system design as something that you really should read. The book was “Fortress Rochester”, written by Frank Soltis, and published in 2001.
I just read an article from IEEE Annals of Computing history about the COMIC Color-Matching Analog computer built and sold by Davidson and Hemmendinger, a US firm. It seems the computer is pretty well known inside the colorant industry, actually, and it provides an interesting example of how to do a good-enough solution to break open the market – while leaving the user in control of the process to build faith in the approach.
I find the subject of fault tolerance and resiliency in computers quite interesting. It also very interesting to look into what kinds of faults actually do happen in the real world, and what impact they have. I recently found a couple of good sources on this. First of all, a paper from Super Computing 2012 by Fiala et al, called “Detection and Correction of Silent Data Corruption for Large-Scale High-Performance Computing” (ACM Digital Library). One of its references was to a 2011 talk by Al Geist, “What is the Monster in the Closet”, which provided some more data on how common faults are.
I am using the “Webex productivity tools” at work to quickly schedule and start meetings from within Outlook. It really is a very useful piece of software for those of us that do quite a few Webex conferences each week. However, it came with one annoying side effect: little webex tabs started to appear on select application windows. In particular, on top of Skype windows.
When mobile phones first appeared, they were powered by very simple cores like the venerable ARM7 and later the ARM9. Low clock frequencies, zero microarchitectural sophistication, sufficient for the job. In recent years, as smartphones have come into their own as the most important computing device for most people, the processor performance of mobile phones have increased tremendously. Today, cutting-edge phones and tablets contain four or eight cores, running at clock frequencies well above 2 gigahertz. The performance race for most of the market (more about that in a moment) was mostly about pushing higher clock frequencies and more cores, even while microarchitecture was left comparatively simple. Mobile meant “fairly simple”, and IPC was nowhere near what you would get with a typical Intel processor for a laptop or desktop.
Today, that seems to be changing, as the Nvidia Denver core and Apple’s Cyclone core both go the route of a few fat cores rather than many thin cores.
The purpose of the free chapter is to provide a way to understand the style of the book – and hopefully lead people on to buy the whole thing to read it.
The paperback edition looks really nice, and the printed copies that I have had the honor to get have been very well made.
At the Wind River corporate blog, there is a blog post that I wrote about continuous integration and Simics. At the Elsevier Computer Science Connect blog, there is also a blog post about continuous integration and Simics that I wrote. These two texts are essentially the same, and I had the good fortune to get it posted in multiple places. The reason it is up at Elsevier is to help promote our soon-to-be-released book at about virtual platforms and simulation (and a little bit about Simics), and hopefully we will reach a larger audience with both messages: CI with Simics is a great idea, and the book is a great book to buy.
I just found and read an old text in the computer systems field, “Why Do Computers Fail and What Can Be Done About It?” , written by Jim Gray at Tandem Computers in 1985. It is a really nice overview of the issues that Tandem had encountered in their customer based, back in the early 1980s. The report is really a classic in the computer systems field, but I did not read it until now. Tandem was an early manufacturer of explicitly fault tolerant and highly reliable and available computers. In this technical report Jim Gray describes the basic principles of fault tolerance, and what kinds of faults happen in the field and that need to be tolerated.
Recently, I finally got to ride (if that is the right word) a Segway two-wheeler. Quite fun, actually. But when thinking hard about it, it really seems like a pretty pointless invention. Cool technology, fantastic control system design and programming – but still, it does not solve any real problem. As a product manager, my mind tends to view new things with an eye toward “what is the problem they are trying to solve” rather than how fun, attractive, or well-designed they are. Sometimes, good design is the point, of course. However, in this case, we are talking about a transportation device, and as such, the question is where it fits.