2013

My cousin’s working on an interesting project at the Agastya Foundation. A group of scientifically inclined volunteers go around on a bike to schools, taking with them a science lab kit, and show children in rural schools a variety of experiments. Google will award this and 3 other projects (out of 10) Rs 3 crores based on public votes. You can vote for and read more at https://impactchallenge.withgoogle.com/india2013#/agastya|vote Comments Motorbike science lab http://t.co/WWsD9YxGEX - Thej Live 25 Oct 2013 2:14 pm (pingback): […] Motorbike science lab s-anand.net/blog/motorbike… […]

We are often subject to body searches, baggage inspections, and identity verifications. At malls. At airports. At offices. These are to ensure that no one carries ammunition inside, or goods or secrets outside. In other words, to deter terrorists and thieves. It’s nothing personal, of course. When someone does not know me, I can choose to accept that (or not; the choice is mine). When I’m invited somewhere, however, I assume that I am not deemed a security threat. Therefore, I expect that: ...

[This is a post that I’d published internally in InfyBlogs in Dec 2009. Time to share it.] Last month, my first application went live. I’ve been writing code for 20 years. Not one line of my code has been officially deployed in a corporate. (Loser…) It’s a happy feeling. Someone defined happiness as the intersection of pleasure and meaning. Writing code is pleasurable. Others using it is meaningful. But this post isn’t quite about that. It’s about the hoops I’ve had to jump through to make this happen. ...

I’m not that difficult to scare, and this log message certainly didn’t help: ip223.hichina.com [223.4.183.127] failed - POSSIBLE BREAK-IN ATTEMPT! That’s the message I saw – one thousand five hundred and seventy times yesterday in /var/log/auth.log on one of my Amazon EC2 instances. Someone, presumably from China, has been patiently trying out a variety of SSH keys to log into this system. These were grouped as batches. There were exactly 314 attempts at 8am yesterday, then 314 at 12noon, then 314 at 4pm, then 314 at 8pm, then 232 at 3am today. (All times are in UTC – that is, UK time without daylight saving). Every burst took 9 minutes to run through all 314 attempts. The worst part was, when I tried using SSH this morning, I wasn’t able to log in. (It turned out that I had made a configuration error, but this is the sort of thing that gets me quite worried.) Perhaps I shouldn’t be complaining. I’ve written enough scrapers to make most webmasters cringe at their logs. I remember a few years ago, when I was working on a project at Tesco, and was scraping bestsellers lists from most sites. (Here’s a blog post about it.) We were putting together a prototype to see how real-time competitive pricing could help. The scraper was a pretty mild one. It would visit a hundred links, roughly at the pace of one a second. No images were loaded, of course, just the HTML. One fine day, a few weeks after this had started, I got a call from Andy. “Hi Anand, are you running any scrapers on our books website?” “Yes, why?” “Oh! The site’s very slow. Could you shut it down immediately?” Turns out that not a single page on the site loaded, and it had almost crawled to a halt. Now, obviously, my little 100-page script could hardly cause damage, but it’s easy to understand their reactions. No unauthorised scraping! After a few days of trying to figure out what the problem was, they increased the memory and things went back to normal. Not a bad solution, actually – throw hardware at the problem, and if it vanishes, it’s probably the cheapest solution. But anyway, I’m sure it’s some nice chap who’s just curious to know what I’ve got on my servers. I’d be happy to share some of it. And even if it’s not so nice a chap, there’s little that I can do, is there? Update (1pm India, 3rd June): Actually, I now realise that this has been happening ever four hours since May 29th, as regular as a clockwork. Wish I knew enough UNIX programming to pull a prank… ...

I've been trying out a number of options for hosting recently, and have settled on Amazon spot instances. Here were my options: Application hosting, like Google AppEngine. I used this a lot until 2 years ago. Then they changed their pricing, and I realised what “lock-in” means. I can’t just take that code and move it to another server. Besides, I’m a bit wary of Google pulling the plug. Heroku? Same problem. I just want to take the code elsewhere and run it. Shared hosting, like Hostgator. This blog is run on Hostgator and I’m extremely happy with them. But the trouble is, with shared hosting, I don’t get to run long-running processes on any ports I like. Run you own servers. The problem here is quite simple: power cuts in India. Dedicated hosting, like Amazon EC2, Azure, GCE, etc. This remains as pretty much the main hosting option I’m a price optimisation freak. So I ran the numbers for a year’s worth of usage. I was looking at the CPU cost of a large machine with 7-8GB RAM. Bandwidth and storage are negligible. The cost per hour worked out to: ...

Some slides from my talks on visualising networks. (These are part of a series of talks I’m giving at a number of forums; the one at The Fifth Elephant is open to public.)

It’s easy to convert addresses into latitudes and longitudes into addresses in Excel. Here’s the Github project with a downloadable Excel file. This is via Visual Basic code for a GoogleGeocode function that geocodes addresses. Function GoogleGeocode(address As String) As String Dim xDoc As New MSXML2.DOMDocument xDoc.async = False xDoc.Load ("http://maps.googleapis.com/maps/api/geocode/" + _ "xml?address=" + address + "&sensor=false") If xDoc.parseError.ErrorCode <> 0 Then GoogleGeocode = xDoc.parseError.reason Else xDoc.setProperty "SelectionLanguage", "XPath" lat = xDoc.SelectSingleNode("//lat").Text lng = xDoc.SelectSingleNode("//lng").Text GoogleGeocode = lat & "," & lng End If End Function Comments Ryan 8 Jun 2015 9:28 pm: I find this isn’t working and says, Compile Error; User defined type not defined xDoc As New MSXML2.DOMDocument what do I change to fix it? Thank you Richie Lionell 27 Jul 2016 6:40 am: Ryan, Inside the VBE, Go to Tools -> References, then Select Microsoft XML, v6.0 . If that doesn’t work unselect that and select Microsoft XML, v3.0

Google Reader was where I spent most of my browsing time, but now, it’s shutting down. Time for alternatives, but not just for Reader: for all Google products. I’m not sure when one of these might go down, become paid, or become unusable. I just uninstalled Google Drive and Google Talk. but I don’t use it much (I use Skype), so no loss. I’ll leave Chrome for the while, but I’m hearing reports that Firefox is improving faster than Chrome is. Or there’s Chromium. ...