Symbolic Links in Unix & Linux

Symbolic links have played vital roles in many of linux development that I have been involved in. Hence, I thought it would do justice to write something on them.

Symbolic links are of 2 types - soft vs hard links.

 

·         Soft links are pointers to programs, files, or directories located elsewhere (just like Windows shortcuts)

·         Soft links don’t die if the source is deleted

 

·         Hard links are pointers to programs and files, but NOT directories

·         Hard links don’t die if the source is deleted

 

Let’s look at some commands to play with symbolic links.

 

Creating a symbolic link:

[yassar@machine data01]$ ln -s pointingToFolder linkName

This will create the linkName pointing to the folder

Displaying symbolic link(s):
[yassar@machine data01]$ ls -la
lrwxrwxrwx.  1 yassar yassar   35 Apr  2 21:35 workspace -> /data/workspaces/branches/Trunk_V3.0.1

 

This would display the folder details together with the actual link path

Updating a symbolic link:

[yassar@machine data01]$ ln -s pointingToDifferentFolder existingLinkName

 

This will use an existing link to point to a new folder

Deleting a symbolic link:
[yassar@machine data01]$ rm latest previous

 

This simply deletes the link.

 

Once you’re in the link directory, you may check the actual path:

[yassar@machine data01]$ pwd -P

 

 

 

Apple - Once you have one, you wanna have more of it!

Well Apple recently announced their mind-boggling results. Even without an iPhone 5 they were able to shake the markets and tremble competitors. At one point of time, Steve Jobs said that he wanted to emulate Sony’s model of product development and marketing. And it is 2012, when Sony posted a net loss of a $1 billion and announced that they would like to emulate Apple’s product development & marketing model. What an irony!

 

 

Anyhow, Apple announced a result which would put any global giant into envy. They went on to become the largest corporation in the world based on market capital outstripping Exxon and if I remember correctly, it was a whopping $450 billion. Apple posted revenues of $46.3 billion for the last quarter of 2011 and an astonishing $13 billion profit. Amazingly, Apple’s profit alone was more than Google’s Q4 revenues which was at $10 billion and was more than double the annual revenue of Facebook. Microsoft has done very well too but clocked $17 billion in revenues. Keep in mind that these are all giants and not to be undermined just because they were overshadowed by Apple on earnings. These are all huge corporations with great talent and ideas. They are in the same league. However, we can say that Apple is in a league of its own!

 

 

This gargantuan result could be easily attributed to the 37 million units of iPhones sold by Apple. With rumors around the Apple TV doing the rounds, who knows where Apple would land.

 

 

Perhaps, I should blog next on the success factors of Apple…

 

Facebook IPO - The Holy Grail of all IPOs !

Facebook has always been in the news but its decision to go public has made recent waves. Well, the obvious question is – why does a company like Facebook need to go public?

 

As a matter of fact, Facebook is not going totally public. An estimated 5% of the company is up for sale and it’s almost like it’s being forced to. How? Well, Facebook is unofficially worth close to a whopping $100 billion and all this money came from private stakeholders. And by worth, I mean market value – the potential of the company as considered by investors. Currently, Facebook has 500 such private shareholders and by law if the figure crosses 500, then you need to make financial disclosures. As a result, Facebook was pedantically instructed to disclose financial statements every quarter as is the case with all public companies. However, Facebook decided to go partially public and raise some funds via an Initial Public Offering(IPO) and this partial stake of the company is worth $5 billion. This is by far the biggest IPO for any technology company !

 

So what does Facebook plan to do with this big pile of cash? Facebook is already rich and popular. It has loads of money available for its expansion plans and is growing at a rapid rate. It already has 800 million users and through user focused advertisements, it is generating its revenue. Today, they reported a billion dollar worth of profit against a $3.7 billion revenue which is a remarkable figure for any company. Anyways, this huge pile of cash from the IPO will present Facebook with additional opportunities in terms of buying hot startups and generating new ideas and products. It will aid compete with rivals by quickly adopting new technologies and innovating marketing tactics.

 

 

The IPO was supposed to be announced this week, but no news yet – potential investors are keeping fingers crossed and waiting to plunge. Is it worth plunging? Not sure, since Facebook has already grown drastically. Under-writers are going to evaluate the stock and then come up with a value figure. Analysts, however, feel that Facebook has to grow at an amazing rate of 30% year on year to make this investment really worth. Is it possible? It surely is tough, but not impossible. Tough because when the company is so large, 30% growth on revenue is a mountainous task. Regardless of that, sentiments & speculations mean a lot in the stock market arena and Facebook is definitely the hottest, the fastest, the coolest company on the block. Well only time will tell if the investors get lucky!

SOPA and PIPA – What are they?

SOPA and PIPA – What are they?

 

Recently, you must have heard a lot of the buzzwords – SOPA and PIPA. But, what are they? They made a lot of headlines recently and have subsided as quickly as they gained attention. SOPA stands for Stop Online Piracy Act and PIPA is the acronym for protect IP Act. Both the bills aim at foreign websites that encroach on copyrighted materials and deliver those freely to common public. There is no law today which would stop this infringement against foreign websites like 'The Pirate Bay' or 'Mega Upload'. These are bills which the congress has been trying to pass and once approved will allow the government to take strict actions against websites which infringed copyrighted material. However, these are not something new and have been around doing the rounds for quite some time. SOPA attempts to bring to court such websites, while PIPA aims to block such sites from the internet service provider layer and even filter out such websites on search engine results. Recently, with the stimulation from music and movie industries, these bills gained attention and were to be presented to Congress for an approval. While most of the media companies are for it, all the major technology companies are in fact against the bill.

 

 

You must have heard about most websites which had de-labeled their logos on a January day to denote their non-support towards the bills. These were major companies including Google, Craigslist, Mozilla and Wikipedia, which also included on their site an explanation as to why they are not supportive. The same day, more than 10000 websites went black and more than 7 million people signed petitions on Google.com opposing the bills. Anyways, the current state of things is that decision on both the bills has been deferred until March of 2012 citing the chaos caused due to them. While the Anti-SOPA groups and campaigners celebrate for a short while, Hollywood is disappointed. We'll see what happens next when once again these bills rise from their graves!

 

 

 

Jackson as Binding Framework for JSON

 

For folks who have used JSON as the message format between different tiers of your application, identifying the best possible binding framework must have been tough. With maturity coming into play with time for JSON, there are a host of binding engines. One of the fastest and lightweight I came across is Jackson. Yes you heard it right – that’s the name of the framework!

 

JSON shows a lot of promise due to its low payload size and structure and frameworks to support it will soon pick up steam. Now let’s get down to some results.

 

Jackson is a multi-purpose Java library for processing JSON. Jackson aims to be the best possible combination of fast, correct, lightweight, and ergonomic for developers.

 

Consideration Points

·         Performance oriented framework and lightweight

·         Fastest marshaling / unmarshalling processing

·         Supports Annotations

·         Supports utilization of generated models with ease (with mix-in annotations)

·         Jackson JSON processor is by default an Open Source product, available under: Apache License (AL) 2.0 & LGPL 2.1

·         Joda date time library support

·         Hibernate data type support

·         Supports non-Java JVM languages also e.g. Groovy, Scala, Clojure

·         Relatively more active project vs other frameworks available in market

·         Clean specifications available

 

 

 

Considering the "bigger is better" aspect -- value measured, "tps", is number of documents read, written, or read-modify-written per second -- difference from slowest (google-gson) to fastest (Jackson) is a solid order of magnitude.

 

 

Mobile Travel Apps - On What?

Recently, there has been a lot of traction to woo customers towards exposure of their applications wirelessly over mobile devices. It is the righ

Augmented Reality - Wanna see more than what’s real !

While I do like writing sometimes, but I have the greatest excuse in the world of not finding time for it. Well, I had received an email a couple of days back on a gadget which actually uses the same concept and I, for a moment thought that perhaps this is a good push to kickstart my blogging career.

Well, Augmented Reality(AR) is nothing new and has been around for sometime but the level at which it is being applied today might well be the next GPS-like revolution. From the word itself, Augmented which means increased, the meaning converts to increased level of reality. This level of reality is achieved by mixing the real-world data with statistics and information generated by the computer system. Hence, the result is a mixed reality which is better than the real object in view. This augmentation is possible with advanced sensors, actuators and navigation systems which today is even available in mobile handsets. AR sits between reality and vituality.

As a matter of fact Google have utilized an AR API in their Android phone to develop AR applications.

Here are some examples I wanted to share:

A google device which scans for a fruit and provides information on the nutritional values:



The same device translates language realtime:


A G1 phone which has a camera, compass & GPS receiver which knows where you are and where to guide you to for a restaurant or ATM:


Contact Lens powered with AR ready to see more than the reality in front:


Vehicle cameras which can provide more information than just the road ahead:



Looks like AR is here to stay and will replace lot of keyboards and punches in GPSs and computer systems. With the voice recognition and voice enabled devices getting the final touches after years of improvements, it's not far when we can do and find things without typing at all.