## Tuesday, December 8, 2009

### Remove "right click disabled" from web page

Quick hack. Just for the fun of it.

3. Search for "onmousedown" in the code. This should be
part of some Java script like:

function right(e) {
var msg = "Sorry... Not allowed to copy";
if (navigator.appName == 'Netscape' && e.which == 3) {
return false;
}
else
if (navigator.appName == 'Microsoft Internet Explorer' &&
event.button==2) {
return false;
}
return true;
}
document.onmousedown = right;

4. Delete that entire block of code. Save the page.
5. Re-open page in a browser and et-voila... right click works :)

## Sunday, November 29, 2009

### How to enable open "command line/window here" in Vista by default

Though this option is available by using the right click
option on the mouse while pressing the shift key, you
can enable this feature just by right clicking the folder.

• Click Start, Run and type Regedit.exe
• Navigate to the following location:

HKEY_CLASSES_ROOT\Directory\shell\cmd

• OPTIONAL - [Backup the branch, in case you need to undo the setting later, this can be done by choosing export on the file menu of regedit tool, and saving the file in a safe place. To restore this setting just double click the saved file to merge and undo registry changes.]
• In the right-pane, delete the REG_SZ value named Extended
• Close Regedit.exe

## Monday, November 23, 2009

### SSHd port forwarding not working

Only thing to do is to use "ssh -X"
at every stage please check if the display is pointing to the right place.
If not, please check configuration for X11 forwarding in /etc/ssh/sshd_config

If this is not enabled, say yes and enable it. Restart sshd by going through
/etc/init.d/ssh restart

This should do it.

Vimp: If you are working on windows make sure you have something
that has an X environment.

## Saturday, November 14, 2009

### Linux intel - wimaxd gets killed

Make sure you are starting wimaxd as root.
Else, you will notice that it gets silently killed
with no information at command line. You can
check the log at /var/log though. Starting wimaxd
as super user solved the problem for me.

### Bash bad substitution error - array access

If you ever come across this error while migrating a
shell script from one machine to other, please ensure
that you are using the same shell to execute the script.

Typical error-

i.e if you used "sh filename.sh" to execute the file, please try
running it using "bash filename.sh". It solved the problem
for me. It had nothing to do with malformed braces while
accessing the array nor user permissions on the script.

Good luck!

## Tuesday, November 3, 2009

### Debain/Ubuntu Linux Headers - 3Steps

Installing kernel source with apt is just so simple-
$>sudo apt-get update This will update information from the apt repository.$>sudo apt-cache search linux-headers-$(uname -r) This should return the name of the package with the current kernel headers along with a short description.$>sudo apt-get install linux-headers-$(uname -r) This command will install the kernel headers. ## Monday, November 2, 2009 ### Why does a car slip on thin ice in winter? Because the thickness of ice/layer of water should be only so much that it reduces the coefficient of friction between the wheels and the road to zero (or small enough), while not introducing friction due to its own thickness. Interesting huh? ## Friday, October 30, 2009 ### What is a debain backport? Backports are packages from testing and unstable debian distributions such that they can work with older packages in a stable distribution of debian. Backports are made available so that some of the latest features in unstable and testing versions of debian can also work with older stable versions. ## Monday, October 12, 2009 ### Latex: file ended while scanning use of @writefile This error is typically seen a lot while compiling latex on windows. This can be eliminated by deleting all .aux files and recompiling the latex code. Recompilation should begin by running "Latex" before any other tool, this helps re-generation of the .aux files. Ensure that after deleting the .aux file, you also remove the error that was causing a compilation failure before re-compiling using latex. Errors could be as simple as missing$$signs for math operators. This also works for the following error: Runaway argument? ! File ended while scanning use of \HyPL@Entry. \par l.38 \begin{document} ## Thursday, October 8, 2009 ### What is the SKB in Linux? Skb is usually an instantiation of the structure supported by the linux kernel buffers (struct skbuff). Skbuffs denote the buffers which are used for handling of all packets in the Linux kernel. These buffers are frequently used for interaction with the kernel network stack. ## Tuesday, September 29, 2009 ### Openscmanager failed - Iperf You see this error while running iperf on windows. This error is primarily because you are not running the windows command prompt in privileged mode. To remove this error, close your command window. Right click on the command window option through the start menu and "run this application as administrator" Navigate to the location with the iperf executable, and give it another shot. This should solve the problem. ## Monday, September 28, 2009 ### 60 ghz Wireless Applications (WiGig) Given that you could now have superior performance (doing up to 15 Gigabits per second) with the 60GHz unlicensed radio band, the main question that comes to mind - What are the applications of such a technology? Is it just another technology that finds limited applications of being a single link? As it turns out this radio range has long been used for inter-satellite communications due to the high O2 absorption. This helps secrecy and avoids any sniffing from within the earth's atmosphere. Other applications could be in the direction of TVs connected to set top boxes through such a connection. Though this link is limited only by the distance over which it can be sustained, this radio is now a reality and applications for this product are only limited by imagination. ## Tuesday, September 15, 2009 ### Unknown symbol error - Intel WiMAX Driver Can occur when compiling a driver or the kernel itself. This is typically due to a kernel module not exporting symbols properly. In our case we see it while compiling the wimax drivers and installing corresponding modules. In most cases this can be fixed by changing the EXPORT_MODULE_GPL() function call in all source files to EXPORT_SYMBOL(). and re-compiling all source code. The replacement can be done using sed. ## Friday, September 11, 2009 ### Openssh server control - start /stop/ in debian Commands to control ssh server- /etc/init.d/ssh start /etc/init.d/ssh stop /etc/init.d/ssh restart ### Install Xserver Linux - Debian sudo apt-get install xorg gdm xfce4 or sudo apt-get install xorg gdm fluxbox or sudo apt-get install xorg gdm icewm or sudo apt-get install xorg gdm gnome-core or sudo apt-get install xorg gdm kde-core main thing is "sudo apt-get install xorg gdm" that is the X environment. ## Saturday, September 5, 2009 ### Create jpeg with gnuplot Gnuplot allows you to create and save a jpeg file too. All you need to ensure is that you include the following two lines as a part of the gnuplot code- set terminal jpeg set output filename.jpeg The set terminal line helps to set the terminal type while the second line gives the name of the jpeg file to which the plot is saved. Please ensure these lines are included before the plot command in the gnuplot script. ## Wednesday, September 2, 2009 ### What is the edas similarity score I would really appreciate if someone could provide an insight in to what it really means. It seems that this functionality is only available to chairs. Based on the very useful comments, I am updating this post. The score ranges from 0-100 indicating the similarity of the article to other papers. Lesser the better! Conference chairs use this tool for determining paper similarities. To quote edas "High scores, e.g., above 30, may indicate that parts of the paper have been copied from elsewhere." So beware! The similarity score can be seen or located on your edas submission next to the pdf submission and format checks. ## Tuesday, September 1, 2009 ### Gmail down Yep, just like May 14th.. its down again!! I hope ppl still trust the whole cloud computing! ## Thursday, August 20, 2009 ### Solution to: File ended while scanning use of \@writefile Recently came across this error in latex. This shows up every time I try to compile the code after I first saw this error and restarting my system or the latex editor did not help- > Runaway argument? > ! File ended while scanning use of \@writefile. > > \par > l.110 \begin{document} This error is seen typically because of an incomplete entry in the aux file and can be removed by deleting the file with .aux extension in the latex source. To re-generate these aux files "latex" needs to be run. Note - you have to run latex and not texify or any other tool. Good luck. ## Tuesday, August 18, 2009 ### ping: sendmsg: No buffer space available (Madwifi/Atheros) I set up a STA-AP network Interface fails after approx 2 minutes. ifconfig/ifdown/ifup does not bring the interface back up. Pings show- ... 64 bytes from 192.168.10.1: icmp_seq=12 ttl=64 time=0.819 ms 64 bytes from 192.168.10.1: icmp_seq=13 ttl=64 time=0.673 ms ping: sendmsg: No buffer space available ping: sendmsg: No buffer space available ping: sendmsg: No buffer space available ping: sendmsg: No buffer space available ping: sendmsg: No buffer space available Increasing the queue size by using the following command helped- echo 83886080 > /proc/sys/net/core/wmem_max Do let me know how it works for you. ## Monday, August 17, 2009 ### Latex Error - something's missing maybe a \item Encountered an error in late while compiling references using Bibtex. Typical error seen was- something's missing maybe a \item The solution to this problem is by running "Latex" before running Bibtex since it helps to generate the necessary .aux files. ## Friday, July 31, 2009 ### Error for wireless request "Set Bit Rate" (8B20) Occurs when you fail to specify the rate with- iwconfig ath0 rate 36M ### Changing default page in folder on a webserver The easiest approach is to change the .htaccess file in a local directory. Edit or create the .htaccess file in the local directory to include the following line- DirectoryIndex default.file ## Friday, July 3, 2009 ### Dynamic IP update Whatismy.com allows you to track your IP dynamically every 300 secs using- http://whatismyip.com/automation/n09230945.asp ## Sunday, June 21, 2009 ### Latex Algorithm2e Comment Insertaion Use the following line in the algorithm description- \CommentSty{ //Test comment }\; You can also enable numbering for comments, if numbering is disabled in general by - \commentsnumbered ## Saturday, June 20, 2009 ### Latex too many }'s - algorithm2e Algorithm2e package seems to be incompatible with the ACM latex classes. The error thrown is similar to that shown here - ! Too many }'s. l.1616 } ? The way around this is by including the following lines before including the algorithm2e package as follows- \makeatletter \newif\if@restonecol \makeatother \let\algorithm\relax \let\endalgorithm\relax \usepackage{algorithm2e} Hope it works for all of you! Let me know if you run into any issue. ## Thursday, June 18, 2009 ### ACM Latex \and tag Use '\and' if you need 'another row' of author names. This tag is used as a part of the \author tag in the ACM latex template for paper submission. ### What is the SAR level? SAR level is used to describe the safe exposure level of electromagnetic radiations typically produced by mobile devices for the human body. SAR stands for specific absorption rate, which stands for the amount of radiation power in Watts absorbed by per kilogram of tissue. Hence- SAR = (Electrical conductivity of sample * E^2)/density The FCC limit for public exposure from cellular telephones is an SAR level of 1.6 watts per kilogram (1.6 W/kg). A list of the top 20 handsets for highest and lowest mobile emissions is available on CNET.com ## Sunday, June 14, 2009 ### Debug not working - Bloodhsed Dev C++ If debugging is not working try these two steps- 1. Go to the tools menu, and within the compiler and linker options please enter "-g". Ensure that this is enabled both for the compiler and linker. This essentially enables generation of all debugging information. 2. Also, within the Tools -> Compiler options -> Settings tab. Select the linker option and enable the "Generate debugging information" by saying yes ### Initial declaration used outside C99 mode C99 is a recent standard of C than the one GCC which is used by default. E.g.Declaring the loop counter inside the for loop is only allowed in C++ files unless you tell GCC to use the C99 standard. For C and ObjC, you need to declare i outside the loop. ## Tuesday, June 2, 2009 ### Yahoo Messenger 9 does not connect - Vista I had an older version of yahoo messenger (7) running happily on my machine. While I was hunting for reasons why 9 would not always connect on my machine, despite checking a lot of other reasons such as firewall config etc. I think the eventual solution is by not doing a typical install and NOT installing the yahoo toolbar. This has solved the problem for me. ## Friday, May 22, 2009 ### What is a virtual bridge Virbr0 ? A virtual bridge, can be defined as a device that bridges virtual interfaces. It provides an easy means of networking virtual networking devices such as venet (virtual network) or veth (virtual ethernet). Typically, a virtual bridge Virbr0, has point to point devices such as venet devices. So whenever traffic is directed from the kernel to one of the guest VMs / virtual containers, if the vbridge is configured with the right IP address and subnet information, it accepts traffic from the kernel. Internally, the bridge then forwards the packet to the correct venet interface as it learns their IPs. So the typical configuration is - virbr0 ----------> venet0 -----> eth0 192.168.10.2 | ----- > venet 1 -----> eth0 192.168.10.5 In this case virbr0 could have an IP of 192.168.10.7/24. Hence virbr0 takes all traffic for 192.168.10.0 and sends it to the venets which are typically point-point devices. If you have any questions please post a comment. ### Command to ssh tunnel using vncviewer VNC viewer provides a command line option to tunnel over ssh, without having to run a separate ssh session with X window tunneling. vncviewer -via native@10.49.3.45 vm99:1 The command uses the via switch. In this example, the vncviewer will reach the display #1 of vm99 by running an ssh session through 10.49.3.45,. with the user name native. Such a command is typically useful while accessing virtual machines (such as KVM guests, OpenVZ containers) running on other machines. ## Thursday, May 21, 2009 ### Iperf: write2 failed: Operation not permitted I have seen this error thrown by Iperf over and over again. Can anyone please post a comment and let me know why this is happening? That should be useful. I am guessing this is because iperf fails to establish an end to end socket connection between the client and the sender. ### BSE Trading Simulator For Stocks/Shares For investors who wish to have an experience trading stocks on the bombay stock exchange, an excellent facility is provided by the Singapore Stock exchange. The Singapore stock exchange provides real time stock quotes, for a real time trading simulation. This is one among the best trading simulators available online for free - http://futuressimulator.sgx.if5.com/Default.aspx Do give it a shot. ## Tuesday, May 19, 2009 ### What is the Bluetooth sniper riffle I just learnt today that it is possible to sniff traffic from bluetooth transmission, such as from your wireless headset to your cell phone over almost a mile. The device needed for doing this is called a bluetooth riffle. More information on how to build a bluetooth riffle is available on boing. Considerable number of news reports are available on google that discuss how the riffle can be used to sniff out vulnerabilities. ## Sunday, May 17, 2009 ### 3G service in Mumbai, India Just read an interview from the Mahanagar telecom Nigam Limited (MTNL) chief about launching a 3G service in Mumbai and Delhi. Details are not available as of now. The company is also not discussing possible avenues for generating revenue for the spectrum and the towers. Some discussion is bound to issue with the sharing of cell towers but nothing beyond that. The chief even fails to quantify a possible time in the future (1yr+) when they will possibly break even. This is even when they are hoping to rope in 1 Lakh subscribers@ Rs1000/mo. Interesting to know about this development. It will be nice to see how this affects the share price in the BSE (bombay stock exchange). ## Friday, May 15, 2009 ### Difference between throughput and goodput? Goodput measures the rate of data transmission/reception at the application layer without taking into account retransmissions. Applications like iperf typically report the goodput seen by a typical application layer when operated in TCP. However if iperf is used with UDP, which is a best effort protocol, it is a better idea of the throughput seen on the channel being measured. Throughput is typically measured at layer 2/3 of the network stack, thus including protocol overheads and any retransmission. Hence in quite a few cases the useful goodput is <<< throughput measured. For example in file transmission, the "goodput" corresponds to the file size (in bits) divided by the file transmission time. ## Monday, May 11, 2009 ### What is an earth browser? An earth browser can be defined as a software that allows the user to view 2D and or 3D maps of the earth. Examples of earth browsers are - Google Earth, Earthbrowser.com/. Apart from being a viewer for the maps, the google earth browser also supports a XML based programming interface. The language is called as the Keyhole Markup language (KML) named after one of the first reconissance satellites launched in 76. The KML schema allows the user to place and move objects over google earth as a baseline application based on point co-ordinates of the location. ## Friday, May 8, 2009 ### What is a MATLAB mex file? A mex file is a matlab source type file that allows the user to compile partial code as C/C++ code. MATLAB runs an interpreter for running the code. Since code interpretation is usually slower as compared to running pre-compiled binaries on a machine, MATLAB provides an approach to do this by using the built in mcc tool. These mex files define certain entry points in a standard matlab code where, a function call is translated to a C/C++ code and later accept values from the computed results. Such an approach finds a lot of application with compute intensive operations such as graph search or image recognition which can be done better with optimized C code. ## Thursday, May 7, 2009 ### Difference between Cell Broadcast and MBMS Both services are a part of the GSM standard. However, MBMS is also used with UMTS. Cell broadcast is a part of the GSM standard and is used to send a broadcast message to all subscribers from a particular cell. This service is a pseudonym for the SMS-CB - Short message service - Carrier broadcast. The other version of this service - SMS-PP - point to point link is the version used with the standard SMSs. SMS-CB was designed for emergency purposes where the provider can send emergency message to all users within a cell. With Multimedia broadcast multicast the architecture provides a means for the users of the service to interact with the service provider. Along with the standard broadcast service MBMS provides the advantage of having a two way multicast. ### Possible DNS spoofing detected This is a typical warning thrown in an ssh session that occurs when the public key for the remote machine that you are either trying to log onto or scp onto has been changed. Typical error seen is on this lines - misfit@mufasa:~/ ssh misfit@10.12.12.22 @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ @@@@@@@@@@@@@@@@@@@@@@@@@@@@@ @ WARNING: POSSIBLE DNS SPOOFING DETECTED! @ @@@@@@@@@@@@@@@@@@@@@@@@@@@@@ The RSA host key for node1-1 has changed, and the key for the corresponding IP address 10.12.12.22 is unknown. This could either mean that DNS SPOOFING is happening or the IP address for the host and its host key have changed at the same time. @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ @@@@ @ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @ @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ @@@@ IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY! Someone could be eavesdropping on you right now (man-in-the-middle attack)! It is also possible that the RSA host key has just been changed. The fingerprint for the RSA key sent by the remote host is 2d:47:fd:c3:1a:19:69:f7:ca:35: 2b:cc:b5:69:07:db. Please contact your system administrator. Add correct host key in /home/misfit/.ssh/known_hosts to get rid of this message. Offending key in /home/misfit/.ssh/known_hosts: 1 RSA host key for node1-1 has changed and you have requested strict checking. Host key verification failed. The solution to this is as posted in the message, either the user can clean the known_hosts file and try to login again. The known_hosts file is located in the .ssh folder in the home directory or alternately just changing the entry corresponding to the remote machine in the known _hosts file. ## Tuesday, May 5, 2009 ### What is inside the .ssh folder To go to your .ssh directory do the following - misfit@mufasa:~/$ cd .ssh
After reaching inside the .ssh directory list the contents -

misfit@mufasa:~/.ssh$ls -ltr -a total 64 -rw-r--r-- 1 misfit far_away 622 2006-09-29 11:15 id_dsa.pub -rw------- 1 misfit far_away 668 2006-09-29 11:15 id_dsa -rw-r--r-- 1 misfit far_away 415 2008-09-03 17:28 id_rsa.pub -rw------- 1 misfit far_away 1751 2008-09-03 17:28 id_rsa drwxr-xr-x 60misfit far_away 36864 2009-04-29 17:48 .. -rw-r--r-- 1 misfit far_away 1082 2009-05-05 14:27 known_hosts -rw-r--r-- 1 misfit far_away 622 2009-05-05 14:30 authorized_keys drwx------ 2 misfit far_away 4096 2009-05-05 14:30 . The *.pub entries are the public keys that may be generated by you. The id_* files are your private keys and are usually with permissions 600. The file authorized_keys has information on the public keys for allowing password less logging to this machine. The known_hosts file has information about machines you had previously logged onto (including public keys). Since machines change their public keys from time to time, the public key entries in this file change and need to be amended. Typical entry in a known_hosts file looks like - misfit@mufasa:~/$more .ssh/known_hosts
node1-1,10.11.1.1 ssh-rsa AAAAB3NzaC1yc2EAAA
ABIwAAAIEAw3eXxgVyiF7UDkKGQ13WyIJ/J1h1
G3xmVVddYJyiHrpHD/LAjmqseQHHtImT+uGW
X8ngzwThGo1wavNBWN9E7GkIiAQ8EhKVJWfQ
f9xZhlrFvfO8Qe5Hyy3

Hope this was useful. If a public key is no longer valid.
Remove the appropriate entry from this file and re-login
to repopulate this entry.

## Monday, May 4, 2009

### Comparison between google's Bigtable and amazon simpledb

Recently I have seen a lot of disucssion relating to
the comparison between the much touted Google
Bigtable database and the Amazon SimpleDB solution.
The BT (bigtable) is an internal database system used
for different projects which could be made open to public.

Amazon's simpleDB solution is currently available to
level of comparison shows up in terms of pricing of
the service. Some articles such as this and a
couple of others discuss the pricing issue.
Some even contemplated the Google service being
free.

Another factor is the ease of use. Some articles contemplate
and debate that the Google approach would not only
try to compete based on size but also on the basis
of functionality. Since Amazon is known to provide
bare bones services in most cases, (sometimes
requiring third parties to develope and build on it),
the users are expecting google to provide a better
usability model.

An approach to give a shot to the google's bigtable service as a
testride is available here - http://bigtable.appspot.com/
This provides a web interface for working and creating tables
that can be accessed from the web.

A possible plus working with the amazon solution could be
easy integration with other services like the amazon ec2 and
(elastic cloud computing) and the amazon s3 (storage).

## Sunday, May 3, 2009

### Maximum number of security cameras - Airport

Recently read a web article which said that
London's Heathrow international airport
had the maximum number of surveillance
cameras. I got reminded of the fact when
I read another related news story that talked
about security cameras that could see through
clothes. Not surprisingly this news was from
London too. The camera - ThruVision T5000
can see through clothes of ppl up to 25m away
and is based on imaging using the Terahertz

### Difference between IP camera and a USB webcam

IP cams are closed circuit tv cameras that were built
with the primary purpose of monitoring and surveillance.
These cameras are capable of working in areas with little
light and good at detecting change in the environment.
Typical resolution with such cameras ranges from 420
to 560 tv lines. These cameras can be connected over
a fast ethernet link to a controlling stations where their
feed could either be displayed on a closed circuit tv or
fed to software for presence detection/analysis. Alternately
their feeds are also recorded and archived for
analysis after a particular incident such as theft/
burgulary.

Web cams are devices that can be used for computer
systems and are used for personal purposes such as
video conferencing (or video chatting for individuals).
Most web cams come with a USB connection for use
with computers. Thes cameras are capable of use in a
well lit environment and for objects in fair focus. It
is important to note that some of the newer webcam
devices are also being considered and used as security
cameras that archive and send videos over the network
when they detect motion/sound/both.

### Resolution of commercial grade security cameras

Some of the latest security CC cameras like the
HDC518 High Resolution Day/Night Security Camera
have a resolution of 560 lines. Other models like
the Swann Model SW-C-BDOGC come with 420 lines
tv quality. Most cameras come in the range of
about $100 to$500.

## Thursday, April 30, 2009

### Command to determine user id in Linux/Unix

User id is an unsigned integer used in the
operating system for a particular user.
The user id can be determined by executing
the id command as follows -
node1-1:~# id
uid=0(root) gid=0(root) groups=0(root)
It is interesting to note that root always has
the uid of 0. Use the -g switch to find out
which groups the current uid is a member of-
node1-1:~# id -g root
0
Another approach to determine the uid of a user
is by grepping through the /etc/passwd file. That
file has all information specific to a particular user.
Another nice thing to remember is that daemons
always operate with an uid of 1.

## Wednesday, April 29, 2009

### How to submit site to google for crawling

The approach to do this is by visiting the webpage -
The page will ask for the URL and some basic details

### How to install centos packages on debian

A package that can usually be installed on a CentOS
distribution is a file that works with the redhat
package manager ( with the extension .rpm).

To install that file on a debian system, I recommend
the use of the alien debian tool. To use the tool
you will first have to connect your machine to the
package repositories.

$> apt-get update$> apt-get install alien

These two steps should install the alien package
on your system. Use the following commands to
generate the .deb file -
$> alien -k your_rpm_name.rpm This takes some time to execute depending on the size of the package you are trying to debianise. After the debian package generation is complete you can use the dpkg tool to install the package as -$> dpkg -i your_rpm_name.deb

Alternately, alien allows you to directly install the
rpm by using the -i switch.

## Tuesday, April 28, 2009

### Minimum interest to get 1099

if the interest you earned in the financial year
is less than $10. However, federal laws require you to report all interest earned. Only interests less than 50c could be dropped due to rounding off. YTD interest paid is available on yearly statements issued by your bank. ## Monday, April 27, 2009 ### W7 processing time It is said that the IRS should take less than 8 weeks for processing the W7 form which provides a new ITIN (income tax identification number) ### Latex package not found Came across this problem the other day. Usually my version of Miktex automatically locates a package from the repository, download and installs it. This time it did not work and due to the absence of the required package my latex code would not compile. An important check to perform would be to find your Miktex version. This can be done by checking different options on your editor or an easy alternative is typing latex on the command prompt which shows the miktex version - C:\Users\mufasa>latex.exe This is pdfTeX, Version 3.1415926-1.40.9 (MiKTeX 2.7) ** ! End of file on the terminal... why? If you are using Miktex version 2.4 or before, you will not be able to download any new packages, as all repositories have been removed and you need to install a newer version of miktex. Follow our post on getting Latex running on windows for more info. ### Working with latex on windows - The 3 step guide There are 3 essential steps to get latex working on windows - 1. Miktex - Miktex is the latex package for windows and must be installed before doing anything. A simple way to get this package is by visiting the site - http://miktex.org/2.7/setup. Multiple options are available for installation, with the most popular and widely used option being the ~80MB installation with popular packages. This is a windows installer file and is pretty self explanatory. 2. Ghostscript and GS View- These applications are majorly required for working with postscript files and strongly recommended for newbies. The installation files can be found at - http://pages.cs.wisc.edu/~ghost/ 3. An editor - WinEdt - Technically the user could work with any editor but my choice is Winedt, because of its particularly simple and intuitive interface. The software is available at - http://www.winedt.com/installing.html This link also has detailed installation instructions - and how it works with Miktex and ghostscript. If you are finding it hard to locate and download any of the source mentioned here, googling the name with a download tag should help you locate a resource. ## Friday, April 24, 2009 ### How to partition with Windows XP having only single C drive ? There are two ways to resolve this issue: 1) Reinstall Windows XP from a bootable CD and create an install partition that is smaller than the total capacity of the hard drive. But with this, everything on the hard drive, including data and applications, will be lost when the drive is formatted. 2) Use any external program like a) Acronis Disk Director Suite (Click For Download) b) PartitionMagic by PowerQuest (Click For Download) c) Partition Commander by V Communications (Click For Download) ## Thursday, April 23, 2009 ### How to resolve blur image/picture problem with logitech webcam? Recently I came accross "Blur Picture" problem while using Logitech webcam with yahoo messenger. I found that even if you select "Broadcast my webcam with - Better Quality" option from Messenger -- > Preferences, image is not very clear. Solution to this problem is : 1) Make sure the Webcam is connected and detected correctly by messenger. 2) Then from Yahoo Messenger main menu listed at the top, select "Messenger" --> "My Webcam" --> "File" --> "Preferences" --> "Webcam" option. 3) Select "Camera Settings" listed at top left corner in "Webcam" option. 4) Adjust "White Balance" value till your image is clear. (I used "7950" and my image was very much clear.) Note: Some times you also need to adjust other values listed on the same page like contrast,brightness,sharpness etc. Enjoy sharing your clear image with your friends/family. Note : 1) You can change any of the image values any time during broadcasting. 2) Make sure that you restart the chat window from which you are sharing your image. 3) "Webcam " option mentioned in step 2 can also be directly selected from chat window from where you want to share your image. ## Saturday, April 18, 2009 ### How to include HTML code in a blogger blog post I noticed that posting html tags (specially misformed ones) results in the blogger throwing an error or displays the content wrongly. There are two alternatives to resolve this issue - 1. The simple approach - It is easy to use this approach if the lines of html code you want to put on your post are small. The only thing that needs to be taken care of is the following substitution - replace all less than, greater than signs that are part of html tags with &ltsemi-colon and &gtsemi-colon. E.g. Consider the following line of html code <img alt="Photo" src="http://URL_to_my_image.gif" /> would be written as - &ltsemi-colonimg alt="Photo" src="http://URL_to_my_image.gif" /&gtsemi-colon in your post to show up correctly on the post. Note in all of the above cases please replace the semi-colon with ; I am not able to include the actual symbol as a single string since it shows up as a < in my post. 2. The second approach - relies on using html framing. You can edit the code in a way to include your html page as a frame in the post. This is specially useful if you are posting a large peice of html code. Hope this works for you. If it does not, please feel free to post comments. ### How to create blogger gadgets? The blogger gadgets are nothing but simple XML files. Each of these xml files are composed of html and optionally javascript code. In this post I will show a simple example where a user can create a simple gadget, include in her blog and then eventually modify and submit the gadget to google so that it could be made available worldwide to all users. The following simple code is the test.xml file which you can upload at your favorite webserver. <?xml version="1.0" encoding="UTF-8" ?> <Module> <ModulePrefs title="hello world example" /> <Content type="html"> <![CDATA[ Test, gadget! ]]> </Content> </Module> Use the add a gadget on your google blog. At the bottom end of the left hand side you will see an option that says add your own. Use that option to enter the URL of place where you are hosting this test.xml file. Adding the gadget from there on should be as simple as adding any other gadget to your blog. Inside a Blogger Gadget - As shown in the code above, the gadget is just a simple xml file that can include html and (optionally) javascript code. This code is a vanilla html hello world program which can be modified by adding other html tags such as the image ( <img> ) tag. In a simple followup to this example I will add an <img> tag to the file to add an image that you can use to display an image in your gadget - <?xml version="1.0" encoding="UTF-8" ?> <Module> <ModulePrefs title="hello world example" /> <Content type="html"> <![CDATA[ Test, gadget! <img alt="Photo" src="http://URL_to_my_image.gif" /> ]]> </Content> </Module> In the above code please change src of the picture to the place where the image is hosted. Upload the code to any webserver and use that URL to add and test the gadget as mentioned above. Please post comments if you see any issues with the same. ## Friday, April 17, 2009 ### Wimax - Difference between Profile A, B and C Setups There is a functional difference between the three profiles for the Wimax technology. The main distinguishing features can be highlighted as - Profile A: The ASN is centralized with the functional units like the BS and the ASN gateway are separated into independent entities. The radio resource management (RRM) is separated into two functional blocks - the RRC which operates on the ASN GW and the RRA which operates on the Base station. RRA - Radio resource agent RRC - Radio resource controller. Links between the BS and ASN-GW is established through the R6 link. Profile B: Considers a distributed ASN side and the BS and the ASN GW functionalities are pushed to a single architecture. All major functionality is a part of the ASN architecture. Profile C: Has all the things as same as the Profile A setup, except that the RRC is also pushed to the BS. There are other minor differences with mobility and handover control, which is moved from the GW to the BS. These profiles are a part of the Release 1. ## Tuesday, April 14, 2009 ### How to find debian distribution version If you are not sure which distribution you are running - Eg Debian, fedora, Ubuntu. You might need to run multiple steps here. However if you know your distribution and just need to check which version you are running distribution specific steps would suffice - 1. Debian - The following command should misfit@mufasa:~/$ cat debian_version
lenny/sid
This shows which version of debian I am running.

2. Other distributions - Redhat/Ubuntu
You could try the following command -

misfit@mufasa:~/$cat /etc/*release* Hopefully either of these option solve your issue. ### How to remove eth0_rename linux There are multiple approaches to eliminate this problem - 1. A GUI based approach - If you are using the Gnome desktop which has the networking tool, the solution is straight forward. Go to the System -> Network -> Administration menu. Select the appropriate interface, and rename it from using that tool. 2. A Command line approach - is as per the guidelines listed in the post here. However to solve this specific problem you need to follow the specific steps. Do a ifconfig on the interface -$> ifconfig eth0_rename

This should have some information like hw addr: aa:bb:cc:dd:ee:ff
Use this hardware address to search the entry within this
file -

vi /etc/udev/rules.d/70-persistent-net.rules

and change the name of that interface to whatever you want -
E.g. eth0. Please note that the name eth0_rename might have
come out due to wrong renaming of interfaces, and hence you might
see multiple entries with the same interface name in the file.

Save and quit the file. Reboot the machine and your woes will
be all gone.

Good day.

## Monday, April 13, 2009

### Umount / Umount2 device is busy

I was playing with a UML installation on debain, and after
finishing stuff needed for the installation, I needed to manually
unmount the partition. So I started with the simple umount -

$> umount /mnt/uml/ umount: /mnt/uml: device is busy So I figured the issue could be solved by a forced unmount which led to - node1-1:~/# umount -f /mnt/uml umount2: Device or resource busy umount: /mnt/uml: device is busy umount2: Device or resource busy umount: /mnt/uml: device is busy Finally, after searching the only solution that seems to do the trick is a lazy unmount - node1-1:~/# umount -l /mnt/uml node1-1:~/# Lazy unmounting works the smart way by detatching the filesystem from the hierarchy as soon as the command is issued and does the reference cleanup as soon as it detects that the device is not busy anymore. An alternative approach to this may involve finding out what operation is causing the device to be busy using utilities like fuser. However doing it the "lazy" way is always easier. ### Difference between Fstab and Mtab 1. Is a configuration file provided on linux based machines for specifying how the file systems are to be mounted. Shows how the filesystems are currently mounted. 2. Fstab is an input file and mtab is a status or output file. 3. Fstab generally has rules which show how all the file-systems should be mounted. Mtab shows only those file systems that are currently mounted (Eliminates those FSes which were unmounted.) ### Different ways to define primary key classes in EJB 3.0 When object relational mappings require a primary key to be composed of multiple persistent properties (i.e. composite key ) the JPA provides following two ways of mapping : 1) @javax.persistence.IdClass annotation 2) @javax.persistence.EmbeddedId annotation in conjection with @javax.persistence.Embeddable annotation ## Sunday, April 12, 2009 ### Vista windows explorer green bar - How to remove it?? There are multiple posts on the net recommending different ways to speed up windows explorer. 1. One of them included changing the views of the folders from detailed to icons. This did not seem to make much difference to the performance on my machine. 2. Another solution was to go to Tools menu -> Folder Options -> General Tab, and selecting the windows classic folder view. My machine was already having that and thus did not contribute to removing the slow green bar at the top of the screen. With classic I have the slow gray bar :) 3. The solution that works for me is - to start with the windows explorer and go to the Tools menu -> Folder Options -> View. Then go to the Advanced Settings and select the “Always show icons, never thumbnails. The final solution is the one that seems to work for me and I think it will work for you too. This solution prevents windows from trying to generate a thumbnail for each video and picture file you are trying to browse through. Please post comments and let me know if this works for you. ### Best time to visit different parts of India Agartala - October to April Agra - October to March Ajanta Ellora - All round the year (Preferably October to March) Amarnath - July to August Andaman and Nicobar islands - October to May Ayodhya - July to September Badrinath - June to September Bangalore - All round the year (Best suitable is durin balmy winter) Bhubaneshwar - September to March Bodhgaya - October to February Chennai - November to March Dadra Nagar Haveli - November to March Darjeeling - mid September to mid December and from mid March to mid June Dehradun - All through the year Delhi - February to April and August to November Diu Daman - October - May Dwarka - October to March Gangotri - May-June and September to November (The temple usually remains open from last week of April to 2nd week of November) Gir - Mid October,Mid June, November and February Goa - October to March Golconda - September to March Gwalior - October to March Haridwar - October through March Haryana - October to March Hyderabad - October and March Kanyakumari - October to March Kashmir - March to October Kedarnath - May to October kerala - All season destination preferably August to March (April to August is considered the best time for getting Ayurvedic treatments) (June & July for monsoons) Khajuraho - October to April kolkata - October to March Konark - October to March Kullu - May to October Lakshadweep - All round the year Leh Ladakh - June to September Lonavala - October and May Lucknow - October to March Madurai - October and March Mahabaleshwar - October to June Manali - May to October Mathura - October to March Mumbai - October to February Mussoorie - Aprilto June and September-October Mysore - October and March Nagarjuna Sagar - October to March Nainital - March to June Nalanda - October to March Panchgani - September to May Pondicherry - September to March Puri - Later part of March or early April Rajasthan - October to March Rishikesh - May-June and September to November Sanchi - October to March Simla - Any time Srinagar - April to June Tirupati - Any time in the year (Ideal time is September to March) Vaishno Devi - March To July ## Saturday, April 11, 2009 ### Ebay virtual game items prohibited? - How to list an item on ebay? Ebay bans the listing of virtual game items such as currency, leveling etc. To get around this you have to ensure that you remove all non-word strings such as Rs2 from the listing. This worked for me. If it does not - contact ebay support. Search for not able to list an item and select a topic that best matches your problem description. If you chose to do a live chat, ebay wil resolve the issue for you right away. ## Friday, April 10, 2009 ### write2 failed: Iperf error I encountered this error today when I was testing performance of a link. I am not quite sure if this error is a bug due to a specific version of iperf, but was able to get around it by reducing the size of the transmitted packet as compared to the MTU. By default iperf uses a 1470byte packet for transmission, cutting down that size below 1440bytes (with MTU of 1500) helped remove the error. Again I am not sure if this is a version error and the solution posted here is just a quick fix. ## Thursday, April 9, 2009 ### Command to check port usage A simple linux command by the name netstat does it. Usage is -$> netstat -a

Using the -a switch shows the ports that are both listening
and not listening at the moment. Such a tool is useful
for debugging services which are connection based such
as webservers and sockets.

### How to install complete kernel source centos

The process has a few key steps -

1. Determine your kernel version by doing -
uname -a

Determine your current distro version by -
cat /etc/*release*

where the ver is based on the version
of the distribution. The kernel src rpm is usually by the name
of kernel-{kernel version}.src.rpm

2. Install the source by -
$> rpm -ivh kernel*.src.rpm 3. Prepare the kernel source by applying proper patches cd /usr/src/redhat/SPECS$> rpmbuild -bp --target $(arch) kernel-2.6.spec If it says that rpmbuild is not found, do a yum install on rpm-build to get the utility. The -bp switch does the patch application. 4. Move and link it; # cd /usr/src/redhat/BUILD/kernel-{version} /usr/src/$> mv linux-{ver} /usr/src/
$> cd /usr/src$> ln -s ./linux-{ver} linux
$> cd /usr/src/linux You are done. The /usr/src/linux directory has all the current kernel source code. Not you need to do this procedure if you need the entire source and not just the current kernel source code. ## Tuesday, April 7, 2009 ### Why is savings rate high in india This comparison is mainly done with developed economies such as US or Europe. Typically the savings rate such as India and China can be as high as 25% and 50% respectively. This may be attributed to the lack of financial security measures like social security which are provided by the government. ## Monday, April 6, 2009 ### What is high relief on a coin Relief on a coin refers to the design of a coin such that it has a high point on the surface of a coin. Such a design is very popular among collectors and requires special effort, since it might require multiple strikes or high pressure to push the metal to the highest point on the die. Mass producing such coins in old times was not possible due to which many coin designs such as the St Gaudens eagle coin was not made available by the US mint until now. ## Sunday, April 5, 2009 ### How to write a shell/C code to obtain Hardware/MAC address We present 6 alternatives to obtain the hardware addresses programatically through a shell script. These scripts may be run independently or may be invoked through C code with the system() calls. Considering that an ifconfig on the node generates the output that yields the following lines - infinity:~# ifconfig eth0 eth0 Link encap:Ethernet HWaddr 00:XX:YY:ZZ:WW:QQ BROADCAST MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:0 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 B) TX bytes:0 (0.0 B) Interrupt:10 Each of the following lines of code can be run independently to obtain the hardware address. Again, they may be invoked through the C system command to obtain the address in C. ifconfig eth0 | grep HWaddr | tail -c 20 ifconfig eth0 | grep HW | awk '{print$5}'

ifconfig eth0 | grep HW | cut -d' ' -f 11

ifconfig eth0 | head -1 | awk '{print $5}' ifconfig eth0 | head -1 | cut -d' ' -f 11 ifconfig eth0 | head -1 | tail -c 20 ## Thursday, April 2, 2009 ### How to check the madwifi driver version I recommend two approaches to doing this - 1. Check the version while the driver loads through logging in the kernel ring buffer. If you missed that and find it difficult to track the ring buffer do the following - a. Clear the kernel ring buffer -$> dmesg -c

b. Remove and reload the driver -
$> modprobe -r ath_pci; modprobe ath_pci c. Check the kernel buffer for the version$> dmesg
....
ath_hal: 0.9.18.0 (AR5210, AR5211, AR5212, RF5111, RF5112, RF2413, RF5413)
wlan: 0.8.4.2 (0.9.3.1)
ath_pci: 0.9.4.5 (0.9.3.1)
ACPI: PCI Interrupt 0000:00:0a.0[A] -> Link [LNKC] -> GSI 11 (level, low) -> IRQ 11
ath_rate_sample: 1.2 (0.9.3.1)
....

Shows the driver versionas 0.9.4 or whatever is your version.

2. Another approach is by locating the installed kernel module
ath_pci. Go to the directory /lib/module/kernel-version/ run the following command at this path to check the
version -
$> strings ath_pci.ko | grep version You should see something like the following on your screen - EEPROM version invalid version=0.9.3.1 srcversion=7E85FB5DC8AA00A7F8867D8 ## Monday, March 30, 2009 ### Can't add venet0 to bridge You may encounter this if you are considering bridging a point to point device. This happens when the P2P device is not a standard ethernet device. I have encountered this problem while trying to bridge the wired interface eth0 with the venet0 interface to the VPSes in an OpenVZ environment. As of the kernel version 2.6.18-openvz-18-51.3d2-486 this feature is not available. ### Command line image manipulation linux Command line image editing is possible by the use of a linux tool named- convert. This tool is capable of converting between image formats as well as resize an image, blur, crop, despeckle, dither, draw on, flip, join, re-sample, and much more. ### What is the difference between resource reference and resource injection in EJB 3.0 ? The Resource references and Resource injection are used to describe the process, "Dependency injection". But they differ as, Resource Reference 1) It uses annotation to reference objects that the container has access to but are not necessarily directly associated with EJB. 2) The resource could be a Database, a JMS destination such as queue or topic, or a timer service. 3) Example, "@Resource" annotation is used to indicate resource reference. 4) Sample Code @Resource(name=”jdbc/OracleDS”, resourceType=”javax.sql.DataSource”) Resource Injection 1) It uses other annotations to inject references to objects directly related to EJB. 2) EJB specific data. 3) Examples include "@EJB" and "@PersistenceContext". 4) Sample Code @EJB( name=”ejb/calci”, beanInterface=Calculator.class, beanName=”calci”, description=”This bean is used for calculations.”) private Calculator calci; Note: You want to set up multiple resource references at once at the class level. Here’s a sample: @Resources({ @Resource(name=”queue”,type=”javax.jms.Queue”) @Resource(name=”datasource”,type=”javax.sql.DataSource.class), }) public class Test{ ... } ## Friday, March 27, 2009 ### Routing/NATing on windows (XP, Vista) A little known feature on most windows machine is that they allowing network address translation for other connections. Say, if you have two wired connections an eth0 and eth1. If eth0 is connected to the internet, you can enable eth1 to have the internet connection and windows does this by running NAT for eth1. This is done by going to the network connections window. Right clicking on the interface that has the internet connection (outbound connection) i.e. eth0 in our case and check the box for sharing the connection with other users on the sharing tab. This will allow the connection to do NATing for other users while putting them on a default network like 192.168.0.1/24. It is a good idea either to configure DHCP on other network clients which could be connected to this machine through a hub or by a cross over cable (wired case). Static IPs on the same subnet can also be assigned. Fore more details lookup information on ICS on windows ### Rename interface eth in linux It is possible to change the name of the device E.g. eth0 to something like eth-intel if your machine is using udev to populate the device entries in sysfs. Edit the file - vi /etc/udev/rules.d/70-persistent-net.rules as root or a power user and change entries with eth0 to whatever you desire. udev support is available for most kernels in the 2.6 generation. For older kernel versions there might be tools such as hwconfig or mii-tools available which could do the job. If you are using a Gnome/KDE desktop, the networking/management tools on the GUI provides a mechanism to change the name of the interface from ethX to ethY. This facility allows direct renaming of the interfaces while changing the udev rules itself. ## Wednesday, March 25, 2009 ### Difference between sockets and RPC calls Both mechanisms are intended for doing similar stuff. There is a difference in the way they are invoked and the way they operate (which can be found in tons of individual tutorials). However the key point to note is that both mechanisms are still similar. RPC's can be thought of as an abstraction running over sockets. Sockets in turn are a crude transport mechanism (like UDP or TCP) which can be used to send just about anything. RPCs can be thought of as sending formatted information over sockets. Check out our other post for differences ## Tuesday, March 24, 2009 ### Break column in latex references Latex has a beautiful tag which goes as - \vfill\eject This tag is to be inserted in to the .bbl file that is generated (bibliography). The tag is to be added before the reference entry where you desire to end the current column and start from the top of the second column. Ensure that you do not re-generate your bibliography as this will wipe out the tag entry. Please post a comment if you have questions regarding the use of this and we will try to reply at the earliest. ### Run wireshark from command line (Linux) A nice alternative to running wireshark in a GUI environment is to run tshark. This feature provides similar functionality to the conventional wireshark tool, but can be run like tcpdump on the console. This eliminates the need to separately sniff and make sense of packets seen on the interface. A simplest example could be to write a binary file$> tshark -i interface -w file.bin

or to write a plain text as -
$> tshark -i interface > file.txt ### Difference short and long retry limit in wlan (802.11) The limits define the number of MAC retries for different types of packets. The short retries are incremented whenever a control frame or a short frame smaller than the rts threshold) is retransmitted. Similarly long retries are incremented when a long packet frame is retransmitted. If either of these retries reach their respective limits (short or long depending on the size of the data frame), the frame is automatically discarded. Madwifi drivers allow to set the retry limit for frames with the command - iwconfig ath0 retry XX With the Atheros family of wireless cards, *nix based machines support a nice utility by the name athstats. Athstats allows you to measure both the short and the long retries for a node on a per second basis. Typical usage - athstats duration The duration value is in secs. Check out our other post for differences ## Saturday, March 21, 2009 ### Free windows XP/Vista software If you are a student at a qualified university and your university is a part of the microsoft academic alliance you could be entitled to install windows software for free on your machine. Check out this this link for the list of schools that are a part of this initiative. More information about the microsoft academic alliance initiative is available here. ### Is it Ram or Rama (pronounciation) Considerable debate has yielded no conclusive response on the real spelling/interpretation of the Hindu diety and warrior. Descendents of northern and western india suggest that the name is Ram and should rather be pronounced as Ram. Indians from the southern region sugest and use the name as Rama and to be pronounced as Ramaa. In fact wikipedia does so too. The issue seems to be the way in which words are transliterated in sanskrit. Rama refers to the pronounciation with an emphasis on "m" rather than as "maa". The pronounciation as aa in sanskrit has a dash on a which is missing in Rama. Hence in english though the spelling Rama could be correct (as per the sanskrit transliteration), it should still be pronounced as Ram. ### Difference between stock and vanilla kernel Most websites do not differentiate between these two terms. However, there have been some comments in the linux communities on the difference. Some say that stock is the same as a generic kernel versions released by Linus on kernel.org while the vanilla version refers to the non-patched baseline images. ## Thursday, March 19, 2009 ### How to upload photos using Picasa Save all your photos in one directory(either from camera or from pen drive etc..) say "Trip photos". Now follow the steps to upload photos using picasa web 3 : 1) If you already have gmail account go to step 3 else go to step 2. 2) To create new gmail account , go to www.gmail.com, then click on "Sign Up For Gmail" at right bottom corner and follow the steps to create gmail account. 3) If you already have picasa web install on your computer go to step 8 else click here. 4) Click on "Download Picasa 3" at right top corner. 5) It will open a pop a window click on "Run" button (First option out of 4 options). 6) Accept the agreement and click on "Install" to install it at default location (Or you can browse the dirctory path where u want to save it using "browse" button). 7) It will ask for few more options to select (select them all or whichever you want (like creating a short cut on desktop etc..)) and finally click on "Finish" NOTE: If you select the options like "Create short cut on desktop" and "Run after finish" it will directly start picasa 3 once you click finish or you need to click on the icon from desktop to start picasa. 8) Once you have started picasa 3 it lists all the folders under "Folders" section from your system including the one which you have created ("Trip photos"). If your folder is not listed under "Folders" section go to step 9 else click on your folder from "Folders" list and go to step 13. 9) If you want to add new folder to picasa containing new photos, click on "import" button (left top corner) 10) Again at left top corner you have the option of selecting the device, select the "Folder" option (you can directly copy from any external device but since we already have copied photos to "Trip photos" directory we will select "Folder" option). 11) Select your folder from proper path and click on "import all" option (available at center bottom). 12) Now it will show all ur photos on left side bar and at the bottom it will show you that it is acquiring some files, that means it is loading all your photos to picasa. Once that process is completed, click on "Import all". It will open a new pop up window where you are going to specify following things: a) Give the same Folder name for your photos on the web(in our case it is "Trip photos" or you can give different folder name). b) Location where these photos will be saved on your local disk (select till the directory where your folder is saved already or any other location u wish) and then click "Finish". It will show all your photos from your directory on right side with your folder added in the Folder section on left side. 13) At right top corner where all your photos from your folders are listed, you have a option called "Share" and besides that there is a small downward arrow key. Click on that arrow key and select option "Unlisted" (This way only those people whom you are inviting to view your album will be able to see it, general public can not see your album. But if your recipient FWD it to some other mail ids even they can view your album so be sure about the option you want to select). 14) Then click on "Share" it will either open a window for login with your gmail id or if u r already logged in the sme browser it will dirctly open a pop up window where you can type mail ids to whom you want to share this album (If you already have mail ids saved in your gmail account, as you type in, it will show you that mail id for auto complete, so you can select them easily). 15) Once u have entered all the mail ids separated by comma, you can change subject if you want or leave the subject as it is. Confirm the album visibility is "Unlisted" (or anything which u prefer for your album) and then click on "Send". This way you will be able to send all your photos in one step itself. Note : When you click on send, it will open one more pop up window where it indicates that it is uploading photos on web... for more number of photos, it may need some time .. so do not close the window unless it says "Finished XX items uploaded(email sent). Once you see this message, it is confirmed that you have send your mails correctly. Note Again:Once you have send the photos you can close picasa by clicking "CROSS" sign at right top corner and continue with other work. Also you can any time delete that folder from picasa folder list (which automatically deletes it from your disk) and click on "Sync" option at right top corner (Just before "Share") to remove it even from your web album list. ### Enabling arp on linux Some devices may be preconfigured with arping disabled. This may be seen either after running: ifconfig interface or by seeing a missing entry in the arp table. This can be fixed by using the following command - ifconfig interface -arp ip netmask netmask E.g: ifconfig eth0 -arp 192.56.78.254 netmask 255.255.255.0 ### Three approaches for enabling proxy arping through a tunnel (Linux) Say you have a device by the name mstun which shows up on your machine. Then to enable proxy arping of all the nodes connected via the tunnel mstun you have to enable proxy arping. This can be done in three ways ($> is the prompt) -
$> echo 1 > /proc/sys/net/ipv4/conf/mstun/proxy_arp OR$> sysctl net.ipv4.conf.mstun.proxy_arp=1

OR
net.ipv4.conf.mstun.proxy_arp=1

to /etc/sysctl.conf

To work with this setup ip forwarding on the machine has to be enabled -
\$> echo 1 > /proc/sys/net/ipv4/ip_forward

## Sunday, March 8, 2009

### Tips to buy cheap air tickets?

Yahoo is running a nice article on tips for cheap air tickets. A couple of take aways from the articles were the obvious - 1. Patience, and 2. shop for odd day tickets.

One of the rather interesting things I found was that airline deals go out at particular times of the day. I am too lazy to type so here is an excerpt from the article: -
It's natural for travelers to book their flight when the workday is done or the kids are asleep. But the airlines are posting fares on their own schedule. They file fares to the computer system that shares them among Web sites and travel agents three times each weekday — 10 a.m., 12:30 p.m. and 8 p.m. Eastern time. It's 5 p.m. Eastern on Saturdays and Sundays. That means fares can change at those times, so when you do see a fare at the price you're looking for, grab it.

## Saturday, March 7, 2009

### Fork Bomb for isolation measurement with virtualization

I am determining if fork bomb is a good way to determine the isolation provided by a virtualization mechanism. I am planning to evaluate the impact of fork bombing an OS level virtualization mechanism like OpenVZ and a para-level mechanism like Xen. Some tests by random users have shown that Xen can withstand such an attack. The question here is ... can OpenVZ do the same?

More on fork bombing here.
Baseline fork bomb in shell:
:(){ :|:& };:

## Friday, March 6, 2009

### Difference between SNAT and Masquerade On NAT

MASQUERADE is most often used in the same settings as SNAT. Using the MASQUERADE target results in determining the IP dynamically instead of using the static IP as provided with SNAT. Though the computation in this process increases MASQUERADE provides correct operation in real world situations where public IPs are often assigned by service providers using DHCP and can change over time.

## Thursday, March 5, 2009

### The 301 redirect

Looking to redirect to your new web address from your old without hurting search engine ratings? 301 redirect is your friend. This can be easily established by creating a .htaccess file and placing it in the web directory (E.g. public_html)
on that machine.

The .htaccess file should have some content like:

Just did this for my old page and works like a charm!
Good luck.

Do not forget to chmod the .htaccess file to 755 before you try this out :)

## Saturday, February 21, 2009

### USB Speeds - By version

Version | Speed
---------------------
1.0 | 1.5Mbps
2.0 | 480Mbps
3.0 | 5Gbps
---------------------

### Static Shock Voltage

Surprising to know that the voltage in
static shocks is considerably high -
in the range of 1000 - 10,000 Volts.
Fortunately the current is significantly
low (of the order of 5mA). Static charges
are generated when two insulating
materials are rubbed against each other.

## Thursday, February 19, 2009

### A two step approach to 3D plots

Step 1: Establish two independent 1D plots (X-Y axes) for the given data.
Step 2: Try to relate the two plots and while maintaining the X axis for each plot, evaluate a combined Y axis based on both variables.

Use matlab meshgrid and surf commands to draw a 3D surface.

## Wednesday, February 18, 2009

### The 2G to 4G Jump

Most mobile operators prefer to stick to their
2G setups for now and looking to switch directly

## Thursday, February 5, 2009

### Wheels spinning in opposite direction

Have you ever seen a car with fancy wheels where
the spokes seem to be moving in the opposiste direction
to that of the movement of the car? Or a old western
movie where the wagon wheel spokes seem to be moving in
the opposite direction?

- This is due to alaising. Our eye is not able to sample
fast enough to capture the movement accurately. In case of
the movies the old cameras had a very low sampling frequency.
The nyquist criterion requires sampling frequency to be
at least twice the signal to avoid aliasing.

## Wednesday, February 4, 2009

### Steganography

Its a nice ancient art of sending messages through picture.
It relies on providing security through obscurity. Eg:
Changing the color of every 50th pixel in a picture to
represent an alphabet.

Very interesting.