Wednesday, December 31, 2008

EMI calculation formula for spreadsheet

Nowadays everyone seems to be taking loans for varying needs such as home, automobile, education etc. We start paying the EMIs per month to pay back the loan as per the bank mandate. Some of us, are tech savvy or nerdy enough to want to keep track of the loan payment by wanting to create an excel sheet for the same. Some time we may want to create an Excel for our monthly EMIs maybe just to calculate how much are we paying in interest and principle per month.

I had to fumble with the EMI formula to make it work in Excel, so here I am sharing the Excel/Google spreadsheet formula so you may use it in your own loan amortization sheet right away!

Use the formula shown below to calculate the EMI for your Loan. The table below shows dummy values, which should result in an EMI of 9983.80
























AB
1Loan Amount1000000
2Loan Interest Rate10.5%
3Loan Tenure(Months)240
4EMI=$B$1*(B2/12)*(((1+(B2/12))^$B$3)/(((1+(B2/12))^$B$3)-1))


I hope this comes handy to you. Do let me know by commenting if yuo have anything to add or you used this article. Wishing you a Happy New Year!

Wednesday, December 10, 2008

India - Now serving DVDs online!

Thanks to the Indian Railways, it is proved that a successfully implemented online venture is very much possible in our dear India too! Ofcource well planned logistics and financial muscle would be required but more and more people in India seem to be willing to tread online for their convenience.

After the grand success of Online DVD renting(think Blockbuster, Netflix) in America, the Indian markets could not have been much behind. And lo and behold, we have our very own offering for the Indian masses. I had heard of companies such as SeventyMM renting DVDs online, but I really never checked it out, untill recently I saw a BigFlix store sprung up in the market near my house. Time to take stock of things.

Yeah, the local DVD walla might offer cheaper rates, but do you really want to use your LCD screen to see a hall print, which you rented at the rate of a DVD? So perhaps it is time to check out these services and enjoy the true DVD quality movies in the convenience and luxury of our homes. Hopefully the customer would end up again being the king with the services competing amongst themselves and offering us the best value of money.

Here I offer a small comparision matrix of the services, though not a review of the same. So without much ado, here is a small compilation I made of some of the services in market:


BigFlix SeventyMM Movie Mart Clixflix
Membership fee Rs. 299 Rs. 250 Rs. 279 Rs. 399
Refundable fee Rs. 400 Rs. 349
Rs. 1998
Registration fee Rs. 0 Rs. 199

Disks at a time 1 1 1 2
Stores in India NA None NA In and around Mumbai only
Late fee after days None 4 None 3
Max movies in a month Once a day 6 Once a day 6
Movies in store > 18000 > 18000

Membership pause facility Yes NA NA NA


You may also check out a nice article I came across at Webyantra titled SeventyMM - national footprint eagerly awaited.

If you have used these services, or prefer any other, do share your say in the comments.

Tuesday, October 14, 2008

Trigerring PHP script by mail

More and more websites are waking up to the need of making the interfaces simpler for the end user. Thanks to a trend popularized by Google, websites nowadays try and reduce the steps required to fulfill tasks online. Efforts are also made to lower the learning curve for the user.

Having said that, how would you like to let your website administrator or even the end uses to interact with your website through their daily email application? You might have already come across some websites which already allow you to do some tasks using your email. A good example is Yahoo Groups. You can read the latest messages to the group on your mail, and you can even post new messages from your email, without the need to visit the site.

I am sure that will really be useful because of the following few points:

  • User does not need to use a new way to do some task. He already knows how to send and read email
  • User does not need to remember more passwords to access the website in question. He has already authenticated if he is reading his email
  • User no longer needs to fire-up his browser, navigate to the website, login and do the task. He can do from his daily email application!
This article will show you how to do so on a classic LAMP(Linux, Apache, mySQL, PHP) configuration.

Bridging the mail and your PHP Script
The first task is to somehow be able to react in PHP to the email sent by a user. For this we first need to activate mail forwarding. I would be using Cpanel in this article to demonstrate the steps, but other web hosting management systems would have some related steps to do the same.

For the same of this article, lets say that you want to do something when your user sends a mail to subscribe@mywebsite.com. To do so follow the below steps:

  1. Login to the cpanel of your webhost for the domain on which your website would be installed. Note that this domain would be the one where your PHP is installed, and where your email account would be for your users to send mails to.
  2. In the ‘Mail’ section, click on ‘Forwarders’
  3. Click ‘Add forwarder’
  4. Under ‘Address’. Enter ‘subscribe’ in ‘Address to forward’. Your full email address would now read subscribe@mywebsite.com. Change the email address in this step to mach your requirement.
  5. In ‘Destination’, click on ‘Pipe to a program’.
  6. Enter the relative path to your script. Let’s say ‘public_html/processmail.php’.
  7. Click on ‘Add Forwarder’ button to save settings.

Processing the email contents once your script is triggered
With the mail forwarding in place, we now need to write the real script to process the mail contents. Here is a sample processmail.php script, which should be kept in the path you mentioned in the above cpanel step.



#!/usr/local/bin/php
<?php
$stdin = fopen ('php://stdin' , 'r');
while (!feof ($stdin))
{$line = trim(fgets($stdin, 4096));
$whole_mail .= "\n".$line;}
fclose ($stdin);
?>


This will read and store the complete email, with all the headers in the $whole_mail variable. Note the shebang (#!) on the top of this script. That is important, and you may need to modify it as per your host configuration.

Remember to give this script enough permissions such as perhaps 755, so that it can be executed automatically. If this script writes/creates files in some folder, then that folder will need to be given apt permissions too.

So now, with the latest email with you, you can write it to database, send additional emails from PHP or do whatever you fancy.

Note, the email received would not be stored in any mailbox, but will be discarded after the script has finished reading it.

Ofcource, the receiving email part taken care of, you can send the users back emails using the friendly ‘mail’ function of PHP. This step too can be automated to be triggered at any predefined interval using the cron jobs. This can be done in cpanel too.

This should now enable you to get great ideas on how you can add a new dimension to the user experience.

If you have more to add, or just have something to say on this article, do post a comment below. Thanks for stopping by!

Friday, July 25, 2008

GMAIL's security, now featuring 'Forget Me Not'

I have been using free email services since long, but GMAIL was the first to offer me the option to access the mail in a safe and secure fashion, using the https://www.gmail.com instead of the regular http://www.gmail.com. Though I do not have the national secrets to guard, but now I have a choice to better protect my privacy, that too for free. The only thing to keep in mind is that, except for the Google login screen, https is not used by default, unless you type it in yourself.

So, if you feel that you need the safety from prying eyes, such as at a public wifi spot or a cyber cafe, then you need to type in https://www.gmail.com instead of the regular http://www.gmail.com. But what if you forget, and maybe unknowingly compromise your credit card number?

Thankfully, now you can let Google do the remember-my-https part. Introduced under the 'General' tab of Gmail 'Settings', you can now find a setting for "Browser Connection". You can select here for Gmail to automatically switch to https everytime. This works even if you visit Gmail from your bookmarks.



More detailed help is always available from the Gmail https help page.

How often do you rely on GMAIL's https feature? Feel free to comment on this post.

Tuesday, July 22, 2008

Top 15 Software For Daily Use

There are a lot of options available to choose from amongst software, applications and tools. One might be tempted and want to try out and play with a lot of them, but at the end of the day, which software do you find yourself coming back to? Here are some software I usually come back to.

I use my Windows computer to accomplish a number of tasks such as communication, education, entertainment, job work, hobbies and more. To help me do what I need to, a plethora of software choice is available today. I tend to have my personal wish list/checklist which guides me to use the software which best suites needs. In this article I have consolidated the software I use, and which I consider as the best software for my need. Though I might have preferences, but the software I choose might be retail, free or Open Source

Code/Text Editor: Notepad++
URL: http://notepad-plus.sourceforge.net/uk/site.htm
Price: FREE

A great editor which can edit text intelligently. It is quite customizable, though it works great out of the box for me. It comes ready to provide text coloring for HTML, PHP, HTML, XML, ASP, C#, Python, Ruby, SQL and more. It can even format XML document, and check for its well formness. Notepad++ also allows you to search for a string inside any number of files residing in a folder(this, by the way, Windows fails to do out of the box). Do you have a long listing of code? Using Notepad++ you can easily creates markers and then you can jump around your code quickly. It has incremental search, macros, plug-in and tonnes of other useful features. Above all, its not heavy and works fast and can save my session too!

Antivirus: NOD32
URL: http://www.eset.com
Price: $64.5

I have been using computers from the days of Nashot antivirus and even before that when we used to have a big PCI slot based hardware antivirus card. So I have used my share of antivirus tools all from Symantec, Mcafee etc. Since long, I have been a patron of Norton, but slowly i started feeling that Norton was getting obese. No offence to anybody, and with highest regards to Symantec I do not doubt it's capabilities at all, but I feel that its no longer value for money for me. It uses a lot of my system resources in comparison to some other competitors. Every release just seems to make it bigger and heavier, with perhaps a new box art. Again, I have not used the latest version so please free to check it out, but this is my personal opinion. Anyway after my hunt for an alternative, I stumbled upon NOD32. It seems that NOD23 has not spent much on marketing, but more on where it matters. It sports a blazing fast scan engine, with detecting and cure rates, not less than what Norton and Mcafee offer.

The download size is about 20 MB.

Compression: WinRAR
URL: http://www.rarlab.com
Price: $21

WinZip has been a staple now since long, but WinRAR is better as per me. It offers better compression ratio and speed to begin with (which, is all that should matter perhaps). Using WinRAR you can split a file in multiple parts, which might be useful for transmission over internet if one of the side has slower download speeds. You can even make WinRAR insert special code in the split parts, so that even if there has been a corrupt download, there are chances of winRAR reconstructing the file.

WinRAR has special algorithms for multimedia files, so promises a better compression there too. WinRAR has other ways to try and squeeze the files more for example by working on all the files as a single file instead of separate files. This way it might find compressible patterns which were not present earlier. As a bonus, WinRAR supports lots of other useful formats including WinZip, ISO and more.

Download size is about 1.2 MB.

FTP: FileZilla
URL: http://filezilla-project.org
Price: Free

I need to use FTP number of times. Sometimes to updates my websites, sometimes to transfer a big file to some friend, or sometime just to download something. FileZilla serves me perfectly on this. It can do wall what is expected from a good capable and reliable FTP client.

For the power users, FileZilla also offers FileZilla Server application.

It's download size is about 3 MB.


Email: Gmail

URL: http://www.gmail.com/
Price: FREE

I have jumped from Hotmail to Rediffmail to Yahoo, and GMAIL is where I am stuck at the moment. I have lots of reasons for that such as great speed, simplistic yet thoughtful design, ability to manage your mail better by using labels, integrated Google Chat and Calendar, Lots of storage, threaded conversations, simply excellent Spam filter and POP3/IMAP access to name a few. If you are still not using GMAIL, you should definitely give it a try.

Browser: Firefox
URL: http://www.mozilla.com/en-US/products/firefox/
Price: FREE

An excellent web browser which blazing webpage rendering speed, and with very useful features. One good aspect of Firefox is of the add-on community, which continuously enhance Firefox's capabilities. And yes, I wrote this article from within Firefox 3.

Word Processing & Spreadsheet: : Microsoft Word and Excel
URL: http://office.microsoft.com/en-us/products/FX101211561033.aspx
Price: $499.95

No need for an introduction here. Each version really does improve, and even though a bit bulky installation now, but the features, capabilities and reliability offered is superb. I prefer these for heavy duty work, or for office work, where documents need to be archived and worked upon. Excel is extremely powerful and capable, offering complex calculation, charts and functionalities.

Image Manager: Picasa
URL: http://picasa.google.com/
Price: FREE

I being a shutter happy type of a guy, love to shoot people or anything which catches my photographic attention. Result being a truck load of digital photographs. It was getting difficult to manage them, and more importantly to find the ones I was looking for until I tried Picasa. Picasa indexes all the snaps, even the ones on your external hard disk and organizes them nicely. You can locate snaps by a timeline of being shot, or by the folder/image names. You can add keywords and captions to each photographs, which help further in finding just the snap you were searching for. Additionally if you later choose to upload your snap to Google Picasa Web Albums, then these captions get transferred to your online snaps automagically!

It would not do justice if I do not mention that Picasa does much more than what I just wrote. Well, believe it or not but you can do superb quick fixes to your snaps to get a professional edit of your snap quickly. Fix red-eyes, straighten a snap, crop, saturate, improve contrast and more easily. The real icing on the cake is that Picasa does not actually alter your original snap until you specifically tell it to. So all edits to a photograph are non-destructive and are stored in a separate file, until you want Picasa to merge the changes, even then a backup of original snaps is made. Nice.

Personal and Collaborative office applications: Google Docs
URL: http://docs.google.com
Price: FREE

When it comes to creating my personal documents, I have slowly started drifting towards Google Docs. It offers working on documents, spreadsheets and presentations. Though not yet as powerful as Microsoft Office, it does offers 90% of the features I need for my personal use. What's more, I can start working on a document at home, and seamlessly continue it in my office, or for that matter anywhere in the world. I can use the nifty Spreadsheet to create nice looking graphs, and if required, can simply share my document online for others to contribute. I can even publish my document read-only and then anybody can see my document from a url. All this, almost at the click of a button. Plus, being from the Google stable, all my documents are completely searchable.

Though I would not be able to cover the loads of useful and thoughtful features offered here, but now I can use Google Apps even without internet, and can import and export from the common file formats such as doc, xls and PDF.

p.s. This article was written as a Google Docs document :)

AntiSpyware: SpyBot-S&D
URL: http://www.safer-networking.org/index2.html
Price: FREE

A free tool which can immunize your PC and search and fix a number of Trojans, spywares and malicious scripts. Must have. This is a slightly bigger download at about 14 MB, but worth it for a clean computing environment, where you know that nobody is sniffing your credit card numbers.

Temporary File Cleaner: CCleaner
URL: http://www.ccleaner.com/
Price: FREE

A quick and painless tool to hunt your system to safely free hundreds of MBs by deleting earmarked safe to delete files. The download is about 2.8 MB.

CCleaner can also be supplemented by users to add custom applications.

Operating System: Vista Ultimate
URL: http://www.microsoft.com/windows/windows-vista/default.aspx
Price: $219.95

I have been using Windows since Windows 3.1, have used XP since long, and agree even before you say that Vista sure had a bit bigger share of issues, but still here are some reasons I liked Vista for. Vista installs fast, it is very reliable, has great self diagnostics(it crashed once, but on next boot it check on the net and told me that my video driver was the cause and was not up to date, which I promptly updated), has a very useful Start search feature(I use Launchy on Windows XP as an alternative), is a pleasure to use. We should understand that Vista was Microsoft’s move to perhaps lay roads for the next generation architecture. Hope for more in future :)

Download Manager: Flashget
URL: http://www.flashget.com/en/download.htm
Price: FREE

Somehow the best download speeds and result I got were from Flashget. It can resume broken downloads, download from multiple mirrors and get that file to you with a better end experience. Recommended. This just a 4.4 MB download.

Torrent Client: uTorrent
URL: Please search on Google.
Price: FREE

Every now and then you may need to share a huge file with your friends and for other related uses, there comes a need for a good and capable torrrent client. For that, I find the above mentioned tool as the best. It focuses on what it does, and does what it claims to.

Text Compare: Beyond Compare
URL: http://www.scootersoftware.com/
Price: $30

Whenever I have two text files or folders containing them, which need comparison, find that Beyond Compare almost always works great for me. It can quickly go through the files and show me how and where they are different. It understand language differences, and knows that an HTML comment is different from a JSP comment. It can compare file using languages rules, binary comparision and file checksum. Good to have at about 2.5 MB.


I intend to update this article with time, but do let me know if you have other such tools which you install or use as soon as you setup a new computer. These are the tool/software you really are addicted to for daily life. And no Windows vs Linux fights please :)

Please note that this article is just my own rambling on what I feel as best for me and you are free to evaluate and feel otherwise.

Do feel free to contact me if you find any inaccuracies or problem with the article and I will promptly try to fix it. Thanks for stopping by.

Sunday, January 20, 2008

5 minutes home wi-fi setup

Recently I purchased a broadband internet connection from Airtel for my new pad in Noida. The setup at home sure took me by storm, with no less than an army of 8 people coming one after another within 2.5 hours to finish every thing from cabling, ADSL phone setup, line activation, internet setup etc.

Soon I had access to always on internet access, but only if I was sitting in the same room and wired to the modem. So as soon as the Airtel army finished their job, I connected my wireless router to the setup. Now I sitting in my inner bedroom, and writing this article on my home wi-fi setup in the comfort of my cozy bed.

Here is how I connected and configured my wireless router with my ADSL Beetle 220bx modem(mind you, my Linksys WRT43G router does not have the default firmware, but dd-wrt):

  1. I assume that your adsl modem has been configured by the company to provide always on internet as is my case
  2. Connect the internet cable from your Beetel modem to the Internet-in port of your Linksys router.
  3. Ensure that your Windows PC is set to automatically receive IP settings by acting as a DHCP client.
  4. The most important step is configuring your router, because I found that by default both the Beetel modem and Linksys router were on the same subnet and were hence conflicting. Hence I changed the router subnet as shown below.
  5. Now turn off both your modem and router. Then first turn on the modem and after about 2 minutes turn on our router.
  6. If every thing went fine then now you should be able to access your modem administration on 192.168.1.1 and your wireless router configuration page at 192.168.0.1
  7. Remember not to give your neighbors free lunch by securing your wireless connection, else apart from you anybody around your house can access your internet and use up your paid bandwidth. Remember that the newer WPA standard s much more secure than the vanilla WEP security. I configured my security as shown below.

I have assumed lots of thing to finish this quick article, so if I missed some glaring steps or tips then let me know and I will update this article.

Even otherwise, do leave a comment! :)