Back after an year

My last post was an year ago! Lot of things have happened in between. I had completed my Masters, majoring in Physics from IISERK, last May and have moved to Singapore to join the Centre for Quantum Technologies (CQT) at NUS for a PhD. My current work is on ultracold molecules, where we are aiming to probe quantum many-body physics in an ultracold Fermi-Fermi mixture of ⁴⁰K and ⁶Li.

Comments

rnoytt said…

Wow!! Seems wonderful to hear about your research topic. All the best!! Keep writing!!

Saturday, November 19, 2011 at 1:52:00 PM GMT+5:30

Making inactve USB Hard Disk spin down automatically in Linux.

I have a 400GB Seagate IDE HDD connected to Mars, our hostel's file-server using an USB enclosure. The USB enclosure is a cheap "Made in China" product. Consequently it has some special "features". One such notable "feature" is that the disk is kept spinning by the controller even if there has been no disk I/O for a long time. I have three other USB disks connected to the same machine, a 1TB Seagate FreeAgent Desk External Drive, a 500GB Maxtor Basics External Drive and a 2.5" 60GB Fujitsu SATA Disk inside a Transcend USB enclosure. All of these spin down themselves if there has been no I/O for sometime. Keeping the hard disk spinning unnecessarily for ever, not only wastes power but also overheats the drive, thereby reducing its life. I tried noflushd, which is supposed to force idle hard disks to spin down, but found it to be of no help. USB enclosure generally work by performing an SCSI emulation over USB. sdparm is an utility which can be use...

Force an application to use VPN, using iptables in Linux

Enforcing an application, for example a torrent client like Transmission , to always use the VPN interface or any particular network interface for that matter, is trivially simple using iptables on Debian, Ubuntu or any other GNU/Linux distro. Personally, I am running Debian Sid on the Raspberry Pi . Occasionally I use it for downloading files ( legal stuff, seriously, believe me :D ) using Transmission Bittorrent client over a VPN connection. Sometimes it happens that the VPN connection fails and doesn't reconnect for whatever reason and Transmission continues pulling stuff directly over my internet connection, which I would like to avoid. Fortunately it is very straightforward to enforce rules based on application owner UID. Transmission runs under the owner debian-transmission in Debian (use htop to check this) and the following two lines of iptables ensures that any process with owner having UID, debian-transmission , will not use any other network interface apart from the...

Rendering LaTeX in Blogger.

Rendering LaTeX in Blogger is pretty easy thanks to the JavaScript LaTeX equation render engine from http://www.yourequations.com . To enable LaTeX rendering go to the Blogger Dashboard --> Layout --> Edit HTML . Then add the line <script> type="text/javascript" src="http://tex.yourequations.com/"></script> <script type="text/javascript" src="http://tex.yourequations.com/"></script> just before <body/> . Half the job is now done. Then, for example to render: \int_{0}^{\pi}\frac{x^{4}\left(1-x\right)^{4}}{1+x^{2}}dx =\frac{22}{7}-\pi Use the code: <pre lang="eq.latex"> \int_{0}^{1}\frac{x^{4}\left(1-x\right)^{4}}{1+x^{2}}dx =\frac{22}{7}-\pi </pre> The LaTeX code will now be displayed as: \int_{0}^{1}\frac{x^{4}\left(1-x\right)^{4}}{1+x^{2}}dx=\frac{22}{7}-\pi Ofcourse Javascript needs to be enabled in the Browser for the renderer to work.

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