Ganesh Swami

Many years ago, I tried playing with distributed version controls. Darcs seemed to be all the rage back then, but somehow I found them to be way too complicated for my uses. Yesterday, I decided to give Git a whirl.

I got it.

Having used Subversion for a couple of years and CVS for more years than I care to remember, I realized that a central repository system was fundamentally broken. It requires one to keep so much in one’s head. I almost always have to execute a svn status before every commit because I can’t remember about files that have moved, changed, deleted, added etc. This also adds a lot of cruft to the metadata of files that have had substantial changes across branch merges.

On the other hand, Git only cares about changes between trees. It cares about content and not files. You diff trees, not files. This is all very beautiful.

I have only scratched the surface. I cheated and took the crash course for people coming from the Subversion world. I haven’t even explored how merges work across branches: they are about five of them in Git.

One day, I will get all of it. Until then, I’ll trust the judgement of the incredibly smart people who work on Git. This is another of Linus’ masterpieces.

PS: Here’s a fairly good explanation of the guts of Git: Git for computer scientists.

I just came back from an awesome 10-day trip to China. We visited 5 cities: Shangai, Suzhou, Hangzhou, Xi’an and Beijing. We drove to Suzhou and Hangzhou from Shangai, flew to Xi’an from Hangzhou and took the overnight train to Beijing from Xi’an.

Only a part-time job

The highlight of the trip was The Great Wall. I was completely blown away — it was nothing like I expected!

The Great Wall

The experiences are far too many for me to write about, so I’ll let you see my photos instead.

Here’s my summary of the hot chips workshop that I recently attended. It was well attended with over 600 people showing up. The organizers also provided lunch on all days and dinner on one day. I learnt a lot, not only from the tutorials and talks, but also from talking to people during lunch and dinner.

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I came across a pure Tamil URL today: http://உதாரணம்.பரிட்சை/முதற்_பக்கம். Searching for such website is hard if ones doesn’t know how to type these.

In other news, lack of WiFi at my hotel encouraged me to walk around downtown SF. I should have gone earlier and rented a bike (shop closes at 6pm.)

I’ll be at Stanford for the next few days for Hot Chips 20, a symposium on high performance chips. Sessions I’m particularly interested in:

• D.E. Shaw’s specialized ASIC for molecular dynamics which I’ve written about earlier and IBM’s PowerXCell powering Roadrunner.
• Upcoming architectures: AMD’s 780G and Intel’s Nehalem (dot products of special interest to me.)
• Chips tuned for network or IO (Sun’s Rock, Fujitsu’s SPARC64VII and Intel’s Tukwila.)
• Algorithmic content: Roofline models for automatic tuning of kernels (good addition to Demmel’s talk on the future of linear algebra from MMDS.)
• Intel’s Larrabee: response to “the can of whoop-ass” (detailed architectural paper from SIGRAPH.)
• CUDA: useful for a class of algorithms (based on memory access.)

I’m going to be trying something new this time — live blogging. I’ll try to push constant updates to my twitter stream : gane5h.

I’ll be staying at the Sheraton in Palo Alto. Drop me a line if you want to meetup for a chat.