My Technophilic Musings

Worried about someone breaking into your house in your absence? Or just need to keep a tab on who enters your room while you are away? Well, all you need is a webcam, a linux PC/laptop and a twitter account. And you are set for real time updates through twitter about all that goes on at your abode behind your back (can even receive a text message/sms on your phone). Keep reading for the very simple setup you need.

1.) Download and install "motion" on your computer. For ubuntu users, this is as simple as running

2.) Setup your motion configuration file. (Usually at /etc/motion/motion.conf). There are quite a lot of options available. You might want to tweak it a lot according to ur needs later on but the most important ones that you can begin with are (leave the rest untouched for now):

2a.) Add/edit the option "target_dir" to point to the directory where you want to save the images of the event when motion is detected.

2b.) Add/edit the option "locate" and set it to "on" so that you get a nice square box around the detected moving object/person.

2c.) Add/edit the option "webcam_port" and set it to, say, "8000". Motion includes a mini http server so now, you can use it to view the actual images of the happening when you get the update and check for false alarms.

3.) Now, comes the most important part, about getting the update. Continue reading »

written by Shantanu Goel \\ tags: fun, linux, motion, motion detection, real time updates, sms, thieves, Twitter, ubuntu, webcam

Did you know that instead of installing special software to view your webcam video, you can simply use mplayer for the same purpose, and with a lot of fine control. e.g. try running the following command with your webcam attached to your computer.

And you can use mencoder to capture and encode video from your webcam:

Have fun playing with the huge number of options available. You could even cat the test.avi file into a folder of your web server and have instant streaming video .

written by Shantanu Goel \\ tags: fun, linux, mencoder, mplayer, stream, video, webcam

I have an old noname cheapo webcam, that I dusted out of my junk (why? More on that in a post coming soon). I hoped that it would work in my Ubuntu setup out of the box like most of my other hardware. I connected it to my laptop's usb port. dmesg gave the following output:

[21328.211333] usb 1-1: new full speed USB device using ohci_hcd and address 2
[21328.319698] usb 1-1: configuration #1 chosen from 1 choice
[21328.439705] Linux video capture interface: v2.00
[21328.458509] zc0301: V4L2 driver for ZC0301[P] Image Processor and Control Chip v1:1.05
[21328.459113] usb 1-1: ZC0301[P] Image Processor and Control Chip detected (vid/pid 0x0AC8/0x301B)
[21328.520576] usb 1-1: PB-0330 image sensor detected
[21328.870287] usb 1-1: Initialization succeeded
[21328.870919] usb 1-1: V4L2 device registered as /dev/video0
[21328.871001] usbcore: registered new interface driver zc0301
[21328.913737] usbcore: registered new interface driver gspca
[21328.913811] ubuntu/media/gspcav1/gspca_core.c: gspca driver 01.00.12 registered

Great! Everything set up, I thought. But running various programs, camorama, camE, kopete, everything gave weird errors like "Connection could not be made", "device not ready" or just showed a blank screen. But soon, after  few trial and errors, I found the solution. Basically the "zc0301" module is the culprit and all you have to do to get your camera working is prevent it from loading. So, this is what I did:

And voila! the webcam started working like magic. Of course, this tip is only for webcams that use this particular chip. And if you want to make this change permanent so that you don't have to run these commands everytime you want to use your webcam, all you have to do is add the following line to your /etc/modprobe.d/blacklist file

blacklist zc0301

This would prevent the module from loading whenever you connect your webcam to your computer. Let me know if this worked for you or if you have some of your own tips/tricks/hacks to get this or other webcams working on linux.

written by Shantanu Goel \\ tags: blacklist, camera, dmesg, gspca, linux, modprobe, ubuntu, webcam, zc0301

HTC announce their shiny new Touch Diamond recently. Everyone ooh'ed and aah'ed while ogling at it until they realized that HTC has taken a step back (or forward towards matching Apple's iPhone crap) by removing the expansion card slot from the phone. Yes, it has 4 GB of internal storage but I'd rather have an SDHC card slot with the ever falling prices of solid state memory (an 8 GB Class 6 SDHC card is worth not more than around 60$ these days). With a history of ultimate-gift-to-mankind phones like HTC Tytn, HTC Tytn II (Kaiser), iPhone, etc that excite so much on the first look and then start becoming dimmer and unwanted as the euphoria settles, we are left to wonder when will we see the real "Super Phone". The do-it-all-be-all-end-all phone.

Well, my prediction is (Nostradamus style) : NEVER. No sir, you are not going to see your dream phone any time soon, or any time at all, for that matter.

Why do I say that. The reasons are pretty obvious, once we take off our wishful thinking hats and don the smart thinking ones.

1. A new dream every day: Around 8-10 years ago, I wished I had a cell phone. Around 6 years ago, I wish I had one with a camera. Around 4 years ago, I wish I had a phone with Mp3 player and expandable memory. 3 years ago I wished for a smart phone. Now, I wish for.... You get it. By the time something comes out, our dreams have already moved on. After all they  aren't called "dreams" just like that

2. Where is the money: You might be ready to give a fortune (and your first born son) for that ultimate phone, but the evil-phone-conglomerate wants much more than that. They want you to be slaves. They don't want the world to spend a huge amount in one go and then stop. They need to mint more money and too much more frequently than you'd like to spend. This is why the strategy works. Give out a phone that has slim form factor, nice UI, wi-fi, but then make the processor crappy (Touch), then lure them with a better processor but take out the wi-fi (Touch Dual), Add the wi-fi back and slap in a keyboard too, but keep'em wanting for better graphics (Kaiser), give 'em a shiny new toy, but then lock it down in every possible (iCrap). So, you'd be stuck in the vicious circle of "upgrades" and keep the phone factory churning.

So, my dear fellow phone lovers, stop wasting your time waiting for that ultimate phone, and go "upgrade" at once, because "that" phone with just "that" one more feature...ISN'T COMING...

written by Shantanu Goel \\ tags: Apple, HTC, HTC Diamond, iPhone, kaiser, PDA, phone, smartphone, super phone, Touch, Touch Dual, TYTN

GLib - An Introduction:

GLib is a utility library for C, which augments the standard C library in several purposeful ways to make your life that much easier while programming. GLib has the following things to offer you:

1. Portability: The main issue that haunts any C developer is the portability of code. One cannot rely on the standard C library for this as you may find many functions that work differently under different platforms are aren't there at all sometimes. GLib ensures that the all the functionality exposed by it remains consistent across platforms, so that you can rest assured that your code will work the way its supposed to work irrespective of the Operating System it's being used for (Of course, this assumes that you have ensured about portability aspects of your non-GLib related source code). Moreover, GLib is available for a vast array of contemporary Operating Systems including GNU/Linux, Microsoft Windows and Mac OS X.

2. Security: Though you still need to be careful about things like freeing allocated memories properly, etc but GLib does ensure that all its functionality is secure. Moreover, GLib has a policy of ensuring that all its functions are threadsafe. This saves you from a lot of checks and balances and locks and scheduling considerations if you had written all this yourself.

3. Useful Data Types: GLib exposes a lot of data types. Some are very basic that maintain portability across OS's and 32-bit and 64-bit systems. e.g. you can rest assured that gint32 will always be 32 bit and gint64 will always be 64 bit data types.

Apart from this, it also provides a lot of derived data types e.g. singly linked lists, doubly linked lists, hash tables, stacks, queues, trees, and much more. It'd basically cover most of you data structure needs that you'd have otherwise had to implement yourselves. And it also provides helper functions that makes working with them so much more easier. If you have ever used Perl, and have wished that C programming could be a bit faster like it, you will be pleasantly surprised.

4. Utility Functions: GLib also provides various utility functions to ease out your manipulation of data. Some of the functions are meant as more secure and portable replacements for those provided with standard C library, while rest are meant to provide other useful functionality which you earlier had to implement in your code. Some of the major areas covered by GLib's utility functions are String manipulation, character set manipulation and conversion (including unicode and base64), using regular expressions, file manipulation, shell functions, config file parsing (my favourite), etc.

End Note: I can understand that there would be a lot of people who believe that use of GLib is dumbing down programming in C. After all, we take pride being in control of our code and this is why we love progrmming in C because we have options to do things in our own way. Yes, that is all true but there comes a time where you'd like to spend more time in developing the core functionality of your app, or focus more on giving a rapid shape to your new idea, rather than reinventing the wheel and fumbling around with writing the helper functions. So, keeping that in mind I believe GLib is wonderful piece of code that has enabled me to churn out new apps that much faster.

written by Shantanu Goel \\ tags: C, data structures, GLib, linux, Mac OS X, portability, Programming, security, utility functions, windows

If you have ever had these errors or just want to be prepared in case they pop up somtime (and they surely will), then read on as I discuss various situations that lead to them and also their solutions.

I generally use desktop clients (mostly blogjet, but also Windows Live Writer and Scribe Fire sometimes) to blog to my WordPress based blogs. Some months ago, I started getting "Http 406: Not Acceptable" error while posting a particular post. Tried posting through the WordPress inbuilt TinyMCE editor, but got the same result. A little bit of research told me that this was because the post contained some words that were considered harmful by the "mod_security" plugin for apache that had been installed by my host to prevent hacking attempts. The quick resolution was to include the following lines in my .htaccess:

Sure enough, I put them in, published the post, and it worked. But since this meant opening up my site to the real hacking attempts, I commented them out and went about my work, occassionally turning them on as and when required.

But, a few days ago, after a server upgrade, the problem reared its head again, and in a more vicious manner. I started getting the dreaded 406 error again, and this time for any post, even a blank post, and through all clients. But this time, TinyMCE was working without issues. A little bit of looking around my site told me that the problem was that my desktop clients were not able to connect to my "x mlrpc.php" file which is responsible for taking care of all the remote api provided by WordPress. Trying to access it through any means provided the 406 error. My site's error log was filled with:

An appropriate representation of the requested resource /x mlrpc.php could not be found on this server.

Now, the xml rpc methods are used not just by WordPress but many other CMS's (like drupal, joomla, etc) and sure enough a quick search resulted in many similar reports for all the platforms. Enabling my previous mod_security options resulted in "503: Server misconfiguration" errors, complicating things further.

On seeing the error logs, I found that the server could not understand the options, and then I discovered that the mod_security had been upgraded to and it wasn't backward compatible with old options. Modifying the options to their latest counterparts also didn't work, as further wading through mod_security manual told me that now, its options cannot be overridden through .htaccess and can only be changed by the web admin.

I found that my host has basically blocked the x mlrpc.php file from being accessed at all instead of using proper rules for blocking only the attacks while allowing valid accesses. This was the problem that a huge number of people are also having and moreover they (like me) are not able to convince their hosts to switch to proper rules.

However, not all hope is lost. I have "fixed" this issue with a workaround for now. It is pretty simple really. Just rename your x mlrpc.php to something else (e.g. myrpc123.php) and also replace all references to it in your CMS with your new file name. You can use sed to automate this task. I used perl however:

Now, the 406 errors should be gone. If this worked for you, or you had any issues let me know. Also, if you have any other workarounds/fixes of your own, do drop me a word.

Note: In the above article, please ignore the space between "x" and "mlrpc" as the mod_security rules prevent them from being in content also. Moreover, use some unique name for rpc file.

written by Shantanu Goel \\ tags: Drupal, Hack, http 406 error, Joomla, not acceptable, wordpress

I installed google toolbar (linux version) today in firefox and for this blog, it says that its page rank is 7. I can't believe my eyes. I suppose it's a google glitch may be (but have a wishful thinking at the back of mind that its true ).

Are you getting the same result for this blog (or weird page rank results for other places that you frequent?)

written by Shantanu Goel \\ tags: firefox, glitch, google, google toolbar, linux, page rank 7

Some of you might know that I was in the hunt for a decent mspaint alternative recently. Note that I didn't go for GIMP / Inkscape etc because they were overkill for what I wanted to do. Many a times, I just wanted to touch up a screenshot or make a simple flow image by drawing a few boxes, use a few pointing arrows, and add some text here and there. All this could be done with the previous mentioned programs as well but took a bit more steps than I wanted (stroking the selections / paths for lines, boxes, circles, and even then, no arrows). I didn't find an adequate replacement at the time but got it now, so thought of writing about it. Basically I came across 4 apps: tuxpaint, gpaint, kolourpaint and mtpaint. Won't discuss tuxpaint here cuz I found it a little too kiddish.

• gpaint: (Available in Ubuntu repositories) gpaint is a very simplistic program that has a mspaint look and feel but feels a bit lacking. It can do basic procedures like basic shape selections, lines, boxes but that's it. No polygon selections, brush, color picker, etc, and yeah no arrows. Moreover, it saves only in pngs.

• kolourpaint: (Available in Ubuntu Repositories) kolourpaint is very close to mspaint. Infact it does a bit more than mspaint. It has all the things that I mentioned as missing in gpaint, plus has basic image manipulation effects as well. I liked it quite a bit, but it had 2 drawbacks for me, still no arrows, and it depends on KDE/Qt libraries.

• mtpaint: (Available in Ubuntu Repositories from Gutsy onwards. Rest of the folks can search for a package on net, or find a suitable package or source here) This is the software that got me most excited. It is actually a kind of lower-intermediate package that lies somewhere between mspaint and a very basic, poor man's GIMP. It has all the features ok kolourpaint, (plus arrows at last ), a small smattering of basic effects (gaussian, edge detection, blur, embossing), can work with gifs also (handles transparency and animation quite well). So, this is the one I would be sticking to for now.

I am using mtpaint now for my basic needs. Hope the article benefitted you as well. If I missed out on some package, then do let me know.

written by Shantanu Goel \\ tags: GIMP, gnome, gpaint, Gutsy, Inkscape, KDE, kolourpaint, linux, mspaint, mtpaint, tuxpaint, ubuntu, windows

I’ve known about ImageMagick tools for quite some time now but never dabbled with it. A couple of weeks ago I played with it for some time (notice the new cascaded polaroid pics header above) and was amazed even more. Few of its shining features:

• It has almost unlimited features to manipulate your images through its tools like convert, montage, mogrify etc and their long list of options.
• It is available for Windows, Linux and Mac as well.
• Runs on web servers also (most of those nifty image sites use it for run time image manipulation)
• It is amazingly fast.
• Runs on the command line, which means batching of operations can be done and is also good for butter fingered people like me who are clumsy with GUI based image manipulation programs
• Has modules for interfacing with C, perl, php, C++, C#, java, etc. So, you can create your own applications around it.
• It’s FREE (as in speech and as in beer)
• It has an amazing documentation over at imagemagick.org and also a very thriving community, so help is just a few clicks away.

As a very rudimentary sample of what it can do for you, take a look at my blog’s header above. I just gave it a few pics and ran a command, and it resized them, turned them into polaroid pics, rotated them at random angles, made the background transparent, strung them together to make a webpage header/banner.

Since the command was specific for the number and names of images, I made a simple perl script to automate the command making process so you can also download this script (link at the end of post) and run it to create your own header. (You might want to tweak the $w and $h variables in the script to specify your header’s width and height). Running it would be like

After I made this script, I came across Stas Bekman’s photo gallery which has a much better and cool stack effect with photos. And he generously agreed to share his script (much more sophisticated than my my few lines) with me. His script is also attached below.

Polaroid web header Creation Script

Stas Bekman's Image Stacking script

Let me know if you use any of these scripts (as it is or after modifying them) to create any cool effects.

written by Shantanu Goel \\ tags: cli, convert, Effects, ImageMagick, images, linux, mac, mogrify, montage, Panorama, perl, Photo Manipulation, scripts, Stack, Stas Bekman, windows

Disclaimer Notes:

1. I wrote this because these things just came into my mind today while I was reading about the impending “Hardy Heron” release related things and saw that there is a lot of FUD being spread still. So, thought of jotting down my likes/dislikes and not making it a linux v/s windows campaign. Though at a few places, it might be necessary to compare the two just to put things into perspective.
2. These are reasons why “I” like/dislike Linux and not why others might like/dislike it although you might find common patterns.
3. Most of my recent experience is with Ubuntu these days, so most examples would be from it as well.
4. These reasons are purely from an end-user’s perspective and not from a linux developer’s perspective. So, I’m not taking into factor that I can change the kernel (or most other things’) source code because “generally” I don’t.
5. This post is quite long. And if you have a flame to send out my way (which you are most welcome to do), please read it in its entirety before doing so, because many things I say at some point have some caveats covered at another point.

5 Reasons why I like Linux:

These reasons aren’t listed in any particular order. All of them are quite important for me.

1. Light on Resources: I must say that Linux is what still keeps my more than 3 years old laptop running in a prim condition with the latest and greatest of everything from technology stand-point as well as eye-candy stuff. An example: With almost every effect of Compiz Fusion turned on, hordes of screenlets and AWN enabled, an Apache/MySQL/PHP based server running, and a dozen of other applications (firefox, nautilus, terminal, GIMP, RhythmBox, Open Office Word Processor, VLC player, etc) open, my setup consumes around 500 MB of RAM. While on the other hand, if I was using Vista, It’d have demanded atleast 1 GB of RAM just to run Aero, forget about the rest of the things.

2. Cost: This is a big factor for me. Almost everything is free or atleast has a free alternative available. Most of the times I’ve found these free software to be much better than commercial software in terms of feature sets as well as stability. But even otherwise, when there are cases where the free alternative a bit lagging as compared to the commercial one (e.g. GIMP v/s Photoshop), I haven’t felt that my needs have ever outgrown the free software.

3. Ease of Use: Doing “stuff” on linux is just so easy. By “stuff”, I mean everything from doing some normal day chores, downloading files, customizing things, automating routine tasks, etc. The backbone for this is “the terminal” (not the movie :P). I can do almost anything I want from the console. It not only saves me time and frustration in executing a program, waiting for the GUI to load and then go through a series of clicks but also allows me to batch up everything into one pretty little command. Moreover, every thing has so many options that I can configure to my liking. (More on the “options” later below)

4. Getting Software: Getting software couldn’t be more easy.

• It generally involves typing in “sudo apt-get install <software>”, pressing enter, and that’s it. The latest version is ready to roll on your machine.
• Reboots are minimal. Even after thinking for quite long, it’s very hard to recall any time when I had to “log-off” my system (let alone reboot) after installing a software (or even a driver)
• Updates are automatic, and not just for the OS or a few core components, but for all the software that I installed through repositories (but not for the ones which I installed from my local deb’s or compilations, which is understandable of course)
• The latest fixes/patches are available very quickly. Moreover, the revision cycle for most distros lies between 6–12 months and hence, even a complete desktop upgrade is quickly available as well (as compared to the 7 year period after which Vista came out). You can even “upgrade” to the latest distro revision without having to wipe everything, though I generally prefer a clean install.

5. Security:Now, I agree with everyone that the reason why we don’t see many viruses for linux is because the user base is very less as compared to other OS’s but I also believe that this is not the “only” reason.

• The thing is that since most of the software is open source, so exploits are found quite quickly and patched and released rapidly. While in a closed source environments, even if a white hat reports it, the exploits go on un-noticed, un-worked upon by the developers (A good example is the recent falling of Vista during the “Pwn to Own” contest because of a known but unpatched vulnerability by Adobe, not a fault of Vista in this case though but you get my drift).
• The security model otherwise is also quite tight and its very hard for someone to exploit it till the time you use common sense along with it. (A linux virus can easily wipe ur “/home” without acqurining root permissions).

5 Reasons why I dislike Linux

These reasons irk me the most but aren’t enough for to make me move away from Linux. I mention them because getting them right would make my Linux expereince that much more joyful and probably others feels the same too. Moreover, this is not a gripe and is not a command/order to “the Linux guys” out there to fix it, because linux is of, by and for the community. And being a part of this community, I share the burden of this equally and would like to help out in making it better in whatever ways possible, developing, testing, suggesting things.

1. Getting Software: I had mentioned about how easy it is to get software from most distros’ repositories with a single command. However, getting and installing software is also a challenge that many people face in linux. After sometime your particular version of the distro stops updating the software and will include only security fixes and such. Now, there are many good people who would backport software for your version but not all the time. You can download pacakges off the internet (debs’ for ubuntu) but they might not work because of too many inter-mingled dependencies. Compiling is another option but many times, it can spiral out of hand. I hope we can better softwares like GDebi that could make this much more easier.

2. Options: Earlier I listed having so many options as one of my reasons to like Linux. But, sometimes, too many options tend to get to my head. This gets even more difficult when you have too many choices but no clue about what means what and which one is the best. However, the community is continously trying to make this right. A lot of documentation projects are going on, and the mailing lists, IRC networks and other forums also give out a lot of information. Especially for Ubuntu, I find a huge community based support system which always helps me out. (PS – The Ubuntu Forums are the nicest forums you’ll ever come across. I am yet to come across a post that contains words like “RTFM” or “n00b”)

3. Ease Of Use: Some times, just some times, the lack of a GUI for common things irks me and I wish in respect of a few things (read wi-fi) that things could “just work”. But I guess this is a trade-off that I can live with, and moreover this situation is also improving especilly due to the efforts taken by Ubuntu, Mandriva, Fedora, GNOME and KDE. (Special thanks to nm-applet ). Moreover, Hardy Heron, b43 and the latest linux kernels promise to solve the wi-fi setup issues.

4. Browsing: The browsing experience on linux isn’t too great. But this is not a fault of Linux as such. This is due to companies providing adequate linux support (e.g. java plugins for 64 bit) and too many sites optimizing their code for IE. But again, there is hope for this as we can already run IE on linux (IEs4Linux) plus SUN has promised a 64 bit java firefox plugin with the next JRE.

5. Drivers: This is again due to companies not giving proper linux support for their hardware and not even releasing their hardware details for the OSS community to develop their own drivers. However, I can understand that giving out hardware details might not be an option for these companies considering the competition, and also proper software support might be a bit unfeasible due to a smaller consumer base. But again, more and more companies are seeing the light now and releasing proper drivers for linux, with Nvidia and ATi taking the lead (When will Creative listen?). And a special thanks to the OSS community for making working drivers despite all this.

So, this is it. After reading back through what I just wrote, I am dead sure that I will stick to Linux as the trade-offs are too meagre for me. Will you?