Posted by Anil Madhavapeddy
Sun, 01 Apr 2007 22:12:00 GMT
It's been a busy old March (release management of the new XenEnterprise sucked up most of it). I did take a break and go over to EuroSys 2007 in Portugal to present the language and compiler I implemented as part of my PhD work (read it here).
Although the talk I gave was was a bit underwhelming (more preparation and time-practise next time!), I met a whole bunch of really interesting people. My argument about rewriting whole applications also didn't get laughed out the room as I thought it might, as people recognise that retro-fitting safety enhancements on existing languages is a bit of a dead-end road to go down. It has definitely inspired me to make more time to spend on polishing up the Melange applications for a proper release in 2007.
In a pleasant surprise, it also won the Best Student Paper award of the conference as well!
Posted in research | 2 comments
Posted by Anil Madhavapeddy
Sat, 30 Dec 2006 01:11:00 GMT
Inspired by finishing my PhD corrections (!) today, I decided to hook up the DNS server from our Melange project up to the Internet. The authoritative server is called deens (since the co-author is one Tim Deegan, geddit?), and is written in pure OCaml.
This is all rather experimental, to put it mildly, but I stuck in the zone file below, hooked it up as a delegate to our main name-servers, checked it against the DNS Report, and it all seems to be working!
$ORIGIN deens.recoil.org. ;
$TTL 240
deens.recoil.org. 604800 IN SOA (
deens.recoil.org. anil.recoil.org.
2006122401 3600 1800 3024000 1800
)
IN NS ns1.deens.recoil.org.
IN NS deensns.recoil.org.
ns1 IN A 194.70.3.132
dynamic IN CNAME dynamic.recoil.org.
static IN CNAME static.recoil.org.
anil IN CNAME dynamic
stats IN CNAME dynamic
I also modified stats.recoil.org to be an alias to stats.deens.recoil.org, so all the requests for that domain will go via the deens setup. You actually need a user/pass to access the site, but that doesn't matter; if it gets that far, the DNS bit has worked.
There's still an awful lot of tedious work to get the server into a production-ready state, such as proper logging, more error handling and recovery, etc., but I really hope to find the time in 2007 to polish this up somewhat. Performance is excellent already; faster than BIND by quite a lot, and it can optionally use more memory to cache responses to shoot up to crazy levels.
Incidentally, the dig replacement utility also seems to be working fairly well, and David Scott has been messing around with a Bonjour implementation that will get finished sometime in 2007 as well (honest!).
Posted in research, hacking, net | no comments
Posted by Anil Madhavapeddy
Wed, 30 Aug 2006 21:35:00 GMT
An oft-cited criticism of virtualisation is that 3D hardware acceleration doesn't work, preventing you from enjoying your hard-earnt game of Quake 3. Rumours abound that Parallels is developing it for its software, and that VMware is doing something in this area as well.
However, thanks to the Google SoC, the power of open-source itching, and the talented Andrés Lagar-Cavilla, Xen now has support for 3D acceleration as well! Check out the xen-gl web-page with screenshots, or just clone xen-gl.hg and get hacking!
Rather than getting down and dirty with foreign grant mappings, PCI pass-through and all that malarky, Andres adopted for the more pragmatic approach of packetising OpenGL using the Chromium project, and creating an x.org module to correctly position the resulting OpenGL. End result: hardware rendering in a guest domain, without requiring any extra hardware privileges. Awesome to the max!
Posted in research, xen | no comments | no trackbacks
Posted by Anil Madhavapeddy
Mon, 10 Jul 2006 11:43:40 GMT
After an invigorating 120 minutes of questioning, bright lights shining in my face, and general all-round cross-examination, my two examiners Ian Wakeman and Tim Griffin decided to pass me with minor corrections for my PhD! On top of that, it miraculously got nominated for a BCS Distinguished Dissertation award, which does motivate me to really polish it up before submitting the final version. At the Volta Lounge, we are planning to graduate together next summer, so there's no rush...
I haven't quite gotten used to it yet; while booking tickets to San Francisco for Thursday I bottled out to the sales lady and put my title down as "Mr." instead of "Dr."!
Posted in cambridge, research | no comments | no trackbacks
Posted by avsm
Tue, 08 Nov 2005 19:25:22 GMT
I've been majorly focused on finishing off my PhD Thesis recently, hence the lack of updates (but check out the sharp green gradient I'm posting on the thesisometer!).
While researching the history of dynamic bounds checking in languages, I found this remarkable quote from Sir Tony Hoare in his 1980 Turing Award lecture about Algol-60:
A consequence of this principle is that every occurrence of every subscript of every subscripted variable was on every occasion checked at run time against both the upper and the lower declared bounds of the array. Many years later we asked our customers whether they wished us to provide an option to switch off these checks in the interest of efficiency on production runs. Unanimously, they urged us not to - they already knew how frequently subscript errors occur on production runs where failure to detect them could be disastrous. I note with fear and horror that even in 1980, language designers and users have not learned this lesson. In any respectable branch of engineering, failure to observe such elementary precautions would have long been against the law.
Bear in mind he made this statement in 1980, and nothing has really changed in the intervening 25 years as the Internet gets overrun by viruses and worms which take down hospitals and nuclear power plants.
Another amusing one is about Fortran, found on his Wikiquote page:
On October 11, 1963, my suggestion was to pass on a request of our customers to relax the ALGOL 60 rule of compulsory declaration of variable names and adopt some reasonable default convention such as that of FORTRAN. [...] The story of the Mariner space rocket to Venus, lost because of the lack of compulsory declarations in FORTRAN, was not to be published until later."
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Posted by avsm
Fri, 16 Sep 2005 14:33:43 GMT
One of the more interesting discussions I had during Ubicomp was with Tim Kindberg and a very nice chap from France Telecom who lived in Japan for a few years. He was very familiar with the state of barcode tagging as deployed in Japan, and these points stood out:
Most barcodes in use here are QRCodes and NTT phones come pre-installed with a reader. Users can also install a UPC barcode reader. The first such use of QRCodes you see is in your passport; the entry stamp has a barcode on the sticker with your id number on it.
QRcodes are so easy to read since most camera-phones in Japan are auto-focus, in contrast to our crappy fixed-focus attempts here. Our tests with QRcode reading using the KDDI cellphones were pretty successful due to that alone.
QRCode deployment in Japan is by no means ubiquitous, as reports in some blogs suggest. You find them on some products (like, oddly enough, tissue packets) but most advertising posters are distinctly QRCode-free. I certainly never saw people clicking on them in public over around 3 weeks of wandering around the country. The telcos here draw a clear distinction between content providers and application providers. Phones aren't quite as programmable as in the West, and so most barcodes take you to a webpage portal with various actions (such as buying the product or just linking it for future reference). Of course, phones in Japan have cheap high-bandwidth connectivity, so this works very well without the long latencies and download times that we have to put up with on our carriers. We confirmed this by playing with the phones KDDI provided at the conference. One really interesting example was that mobile phone bills sent out to people in the post have a QRCode on them, which, when clicked, is stored in one of the phone "barcode slots" in the reader application. Users then go to a post office or bank, and can pay that bill by pressing their phone against an RFID reader (which pays the bills for all the QRCodes stored on the phone). A superb example of a pick and drop interface in the wild.
Posted in research, ubicomp | 2 comments
Posted by avsm
Thu, 15 Sep 2005 15:01:00 GMT
Ubicomp had a pretty strong technical start in the first few days, at least compared to previous years. The last day of the conference was more HCI-centric, but here's a quick summary of what went on from a combination of notes from myself and Al. It isn't entirely complete, as we admittedly blew off the last session to go watch the September Grand Sumo Tournament (which was unbelievably fun, more on that in a later entry!)
We somehow ended up in the Sumo house during the conference... |
... and found the main ring where battle commenced! |
Later, we found the sumo fanbois gathered around their fave wrestlers banners |
Read more...
Posted in research, ubicomp | no comments
Posted by avsm
Tue, 13 Sep 2005 06:37:00 GMT
I'm in Japan at Ubicomp 2005 at the moment, and have been taking notes along with Al using Subethaedit over the dodgy WiFi network here. The conference has been better than the previous ones I've been, most likely since its in Japan where we can sample some of the more exotic technology in use here. Here's some of the more interesting things we've seen in the first couple of days...
In Japan one drinks... |
... eats ... |
.. and enjoys the view... |
Ubiquitous Networking:
Read more...
Posted in research, ubicomp | no comments
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