The first problem was the same as #2 in the problem set for the 9th World Puzzle Championship (Qualifying Test) (PDF). The second problem was the same as #2 in the 2002 US Championship Puzzles. The third problem was the same as #1 in the 2000 US Championship Puzzles. The fourth problem was essentially the same (verbatim, except for the actual numbers) as #22 in the problem set for the 10th World Puzzle Championship (Qualifying Test) (PDF).
Not being someone who solves puzzles regularly (except for Sudoku, of course), I was quite impressed by these problems since most of them involved considering multiple alternatives, proceeding with one of the alternatives and then backtracking and proceeding with another if that proved invalid, continuing till one finds a solution. They should also be fun to solve using computer programs. (I know of at least one person who did precisely that.) I had asked some of the people at the Google booth if I could reproduce these puzzles on my web site to share with my friends, but they were not sure of the copyright issues and clearance for publication. Well, now we know where they got the puzzles from and have found some more interesting puzzles to work on!
Personally for me, it was a mixed event. I could finally meet some of the people whose work I have admired immensely over the years and I also attended a couple of really illuminating sessions. On the other hand, I didn't get to meet as many people as I had hoped to meet and some of the sessions were bad.
Alan Cox was the star of the event as far as I could tell. He was always surrounded by admirers or people just curious to see how he looks. He always had the Red Hat red hat on and talked very nicely to one and all. Like RMS, he seems to have a bit too much of facial hair and has the same habit of frequently twitching as well. I also met Andrew Cowie (java-gnome), Johnathan Corbet (LWN.net), Sirtaj Singh Kang (KDE) and Harald Welte (iptables/netfilter). By the way, I had imagined Harald to be an old person for some reason all this while so I was rather surprised to find a rather boyish looking young man with a lot of enthusiasm and a cool haircut.
I really enjoyed some of the talks, especially on topics that I knew nothing about. Jaya Kumar's talk on how to put together an embedded Linux system, right from selecting the hardware to customising Linux and burning it into the device, was awesome. The guy really knows his stuff and talks with an infectious enthusiasm on a lot of topics. His other talk on GPL and non-GPL kernel modules was also very nice.
Harald's talk on how he figured out what made up his Motorola A780 mobile phone (that runs Linux), hacking his way to getting telnet access to the phone and finally building and uploading updated kernel and applications was also awesome. He followed it up with a live demonstration. The results of his efforts are at OpenEZX.org. By the way, he uses an encrypted filesystem on his laptop to store everything.
There was a talk on hacking the GCC ".md" machine-description files for a quick-and-dirty solution to a code-generation problem and another on using GCJ with SWIG to interface Ruby with Java. However, I felt that these talks were a bit hurried and would have left most of the audience utterly clueless. By the way, the speaker for the former talk, Amber Ved, had recently fractured his left arm and had it in a sling. It was quite evident that it was excruciatingly painful for him but he persisted and managed to finish his talk. All I can say is, "Wow!". However, I still think GCC is severely under-appreciated and I wish I had put together a talk on GCJ or at least GCC. There's so much that has been happening with GCC that people deserve to know.
Another highlight of the event for me was the Google Quiz or "GQ". This was a set of four logic puzzles handed out to whoever they could lay their hands on and if you completed all four, you had a shot at winning an iPod nano. I really enjoyed solving these puzzles and they kept me busy for quite a bit of time.
Unfortunately for me, the schedule of the talks was such that sometimes I had to make a difficult choice of selecting a single talk among three to four very interesting sounding talks and sometimes I wasn't interested in attending a single talk in a given time slot. "You can't please all the people all the time" and all that. But no one can complain that there wasn't enough stuff going on - this surely must have been the biggest FOSS event ever in this part of the world. I am already eagerly looking forward to attending the next year's event. A big THANKS to Atul Chitnis and his gang of volunteers for pulling this off!
"Hello World" Sans Semi-Colons (Java)
Srikanth has a better solution that works with JDK1.5:
public class Sriki { public static void main( String[] args) { if( System.out.append( "Hello World!\n") != null) { } } }
When Srikanth asked me this question, my immediate and disingenious response was to hide the semi-colon using a Unicode escape sequence like this:
public class Sriki { public static void main( String[] args) { System.out.println("Hello")\u003b } }
However, he has a better solution:
public class Sriki { public static void main( String[] args) throws Exception { if( System.out.getClass( ).getMethod( "println", new Class[] { String.class}).invoke( System.out, new Object[] { "Hello"}) == null) { } } }
Can you come up with a better solution?
Delegates from outside Bangalore might want to check out the annual book sale by the great Strand Book Stall while they are here in Bangalore. The venue for the sale is the Chinnaswamy cricket statium and is quite close to the venue for FOSS.in 2005. Veteran bibliophiles in Bangalore would readily tell you how friendly a store Strand is and how you can get some really good deals (up to 80% off) on books during their annual sale. Unfortunately for them, both Landmark and Crossword have now opened big stores in Bangalore. These stores do not usually give you as good a price on books as Strand, but are closer to the watering holes of many young people and have much more space where you can actually sit down and peruse a book at your leisure. I personally get most of my non-technical books from Landmark now simply because it happens to be much closer to my house and my place of work.
"Information Wants to be Free!"
I really hate it when I come across a reference to a paper or a standard and I am not able to read it because I must buy it or be a member of a subscription plan at prices that are atrocious by the standards of developing nations. In my line of interest (Computer Science), the biggest culprits are the ACM Digital Library and ISO. Fortunately, most of the times I can work around this limitation by using Google with a query like '"<title of the paper>" filetype:pdf' or by taking the help of a friend. I really wish researchers use arXiv or an equivalent service more often. The whole point of publishing papers is to help advance your field, not to retard it, right? (Apparently, the situation is still bearable in Computer Science but is unbearably ridiculous in basic sciences like Physics and Mathematics; hence the genesis of arXiv.)
If I ever publish a useful book, an article or a paper, I would try my best to make it publicly available for all.
By the way, my first attempt to burn these to DVDs failed because I had not realised the sundry incompatible formats in which DVDs come. I had access to a DVD+RW drive and I had initially bought DVD-R discs. Thankfully, I could get a refund on all the discs except the one that I had opened.
More Improvements to GCC
Apart from the projects already planned for GCC 4.2, we now have proposals for Link-time Optimisation, New Register Allocation Method and LLVM Integration. The integration with LLVM, should it happen, would be the most significant change to GCC since Tree-SSA. Pretty exciting times for a hacker to be involved with GCC!
Subversion, Old Dog, New Tricks
It turns out that I do not need too much of extra disc space for working on trunk and gcjx-branch using SVN compared to CVS after all. This is because I used to always create a snapshot of GCC sources and use it as a working copy for fear of messing up my checked-out sources. Since SVN always keeps a copy of the pristine sources around (which is the major cause of the increased disc space usage) and it is easy and fast to use svn diff to figure out the damage and to use svn revert to restore sanity, I no longer need to continue with my weird model of development. It is also quite simple to just ignore everything from the GCC SVN repository except for the interesting stuff - for the gcjx-branch, my checkout only has the bare minimum stuff needed to bootstrap C, C++ and Java and run the libjava testsuite, while for trunk I have removed all the Ada stuff since I can't build Ada anyways. Of course, all this would probably have been possible with CVS as well, but there weren't nice instructions in the GCC Wiki for lazy souls like me for doing this with CVS.
So if any of you out there have all these videos already downloaded, would you be willing to burn it to a DVD-R and send it to me? I am of course willing to pay for the cost of the media, package, postage and reasonable labour charges. Drop a message to rmathew AT gmail DOT com if you can. I would prefer the DivX-compressed versions. I had already written to Hal Abelson to know if they provided such a service and they indicated that they don't.
FOSS.in 2005
There are so many talks I would like to attend in FOSS.in 2005, but it happens to fall bang in the middle of a work week, that too at a time when I cannot afford to take too many days off work. Uggghhh!
New HTML Parser: The long-awaited libxml2 based HTML parser code is live. It needs further work but already handles most markup better than the original parser.
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If you're a C programmer with some spare time, take a look at the mod_virgule project page and help us with one of the tasks on the ToDo list!