Can VPNs see my passwords?

So this is something that a lot of us were contemplating. Are VPNs like 'ZenMate' or 'Psiphon' safe to use? We are sending data to their servers first, which is then routed to destination server. So can this intermediate VPN server see credentials like my username and password?

The answer is:
 - They cannot see your password if the website you are accessing is 'secure'.
 - They may be able to see your credentials if it is an 'unsecure' website.

Secure Websites

These are websites like Google and Facebook that have a secure protocol for exchanging data between our web browser and their main servers.

So if you are using a VPN, the data to be sent to Google servers will be encrypted by Google, your VPN encrypts that encrypted data again(thus, adding a second layer of encryption) and sends it to the VPN server which de-crypts it.

Now, even if your VPN server tries to read the information in the packet, it cannot, because it still has that first layer of encryption that only the Google server can de-crypt. So your username and password are safe and encrypted.

To know if a website is secure or not you can check the lock icon on the extreme left of the address bar of your web browser. Click on it for more information about the certification as shown.

Also the website will have 'https(Hyper Text Transfer Protocol - Secure)' as a prefix in green.

Thus it is safe to sign in to gmail.com using my username and password via any VPN.

Unsecure Websites

These websites do not encrypt their data while sending it to their servers. So if you are using a VPN, the VPN will encrypt the data to add one layer of protection, the VPN server will decrypt it and if the VPN server tries to sniff what data is contained in the packets, it may be able to see your credentials like username and password!

This is what an unsecure website looks like:

The is no 'https' prefix and it says that the connection is not encrypted. So it is not safe to sign in using a username and password to gocomics.com via a VPN.

So always make sure the websites that require login are secure for accessing via a VPN!

How to solve 'Battery not recognized' error.

Recently one of my friends changed his laptop battery. He has a Dell Inspiron 15R just like mine.
However he wanted a battery with a better capacity.

Now there are batteries available with different capacities like 48WHr, 60 WHr, 95 WHr and so on. His original battery was 48 WHr. And a battery of better capacity wasn't available for Inspiron 15R. So he went for a Dell Latitude laptop battery which fits into his Inspiron and is 60 WHr. The batter is original from Dell themselves, but since it not made for Inspiron, it gives this 'Battery not recognized' error sometimes. Otherwise whenever it detected it, everything was smooth and the laptop charged the battery.

If you laptop does not recognize the battery then it simply does not charge it. Though it can use it and will work till it gets fully discharged. You can then switch off your laptop and charge it in the switched off state. But this is impractical and tedious.

We broke our heads over this for a long time. Literally scoured the internet. But since the battery was giving a nice capacity which lasted 4 hours, we were reluctant on returning it. Finally found the solution. This does not make the error go away permanently and you will still get it if you don't follow the steps as mentioned below.

Solution 1: Starting without AC adapter

1) Don't plug in your AC adapter in the laptop charging port and just press the power key. Your laptop will start and give this error 90% of the times.

2) Press the power key again. Laptop will switch off.

3) Wait for 2-3 seconds and switch it on again. Miraculously you will not get the error and laptop will boot up and everything will be normal.

Solution 2: Starting with AC adapter

1) Plug in your AC adapter in the wall socket.

2) This is major step now and will take some getting used to. Plug in the DC jack in the laptop port and immediately press the power key within 3 seconds. Only then you won't get the error.

I found this solution on my own, it seems to work for us and may not work for some people. If it doesn't then try out the solutions given on these links.

Dell Community Forum
Raymond Blog

Cheers! :)

How are electronic gadgets made slimmer and compact? OR How are more features added without increasing gadget size?

Edit: 4 Feb 2016 - I got a lot of feedback about this post and many told me it looks rushed. My answer is, that is exactly how I want it to be. If I go into the core technicalities, it will become tiresome for my blog followers from a field other than Electronics. I however, really appreciate the feedback and have added some links to deeper information at the end. Thank you everyone!   

About 80% of what is written here springs from a subject, 'IC Technology' taught in my 7th Sem of Engineering.
--

"How do they reduce the thickness of our smart-phones and make the circuit size smaller?" 

"How come they are offering 128GB of storage in that small micro-SD memory card!?"

I get these questions a lot!

To all of you curious people, I now consider myself qualified enough to answer this and this itself is my career choice! :)
The answer is : Very Large Scale Integration(VLSI) and Moore's Law and we will further discuss it in this post. Hope you enjoy this crash course! :)

VLSI

I am taking you to Semester 3 and 5 of my Engineering. What I am about to talk on is the most basic building block of any circuit(memory cards, processors etc.), that is, a 'Transistor'.
Bottom line: Smaller the transistor, more dense is the circuit or more features can be made available in previous integrated circuit, keeping size same.

This is how more space is made available in memory card without increasing its size! Smaller transistors occupy less space and hence more transistors are fitted to give more data storage capacity.

Details:
Lets say you have a transistor. Specifically a type of transistor called as a MOSFET(Metal-Oxide Semiconductor Field Effect Transistor). MOSFET sounds pretty complex but, for our present scope, lets say it is as simple as pushing a button to switch ON/OFF a light.

Basic diagram of all MOSFETs at the core level: Made using a material called Silicon, its other types and its oxides. 

The ones we use for our experiments in college, have dimensions in centimeters like these:

In the transistor package featured above, a billion transistors can be fitted, in place of just one. However, the package is made purposely bigger, just so that we can handle it. Otherwise even this bigger transistor has a smaller circuit inside, like shown in the diagram. 

To explain the scale we are talking about, in size reduction using VLSI, Apple's A8 processor introduced in the iPhone 6 has a size of 1.05cm x 0.85cm and has 2 Billion transistors. That's VLSI. Each transistor on this chip has dimensions in nano-meters.

This is how an extremely small size transistor fabricated at the nano-meter scale looks like:

This is a special type of transistor, called a FinFET.

They have special laboratories to fabricate components on the nano-scale. They are called nano Fabrication Laboratories or FabLabs. Here is a view of one:

Companies like IBM and Intel came up with transistors which are even smaller(9 nm). They use something called as Carbon Nano-Tubes(CNT) Technology.

Carbon allotropes like Graphene (a single layer sheet of carbon with a thickness of 1 atom) are unleashing a completely new era of electronics! CNT is made by rolling up this Graphene sheet. We will soon have (and already have) technologies like fold-able and roll-able screens, transparent electronic gadgets and micro-circuits which can be extremely useful in bio-medical and wireless applications!

Processors and gadgets's circuits are thus becoming smaller, energy efficient and even more powerful! Now-a-days Systems-on-Chip or SoC are gaining more popularity. The processors in our phones are not just processors or CPU, they are an SoC. SoC means they can do the mathematical processing, as well as the graphical processing and have on-chip memory which makes them blazing fast!

Example: Apple iPhone SoCs

Moore's Law

The co-founder of Intel and Fairchild Semiconductor, Gordon E. Moore postulated that the number of transistors in a dense integrated circuit will double every two years. This postulate became such a common phenomenon that we now call it a law!

For example: A 4 TB external HDD of 2014 is of same size/smaller than 2 TB HDD of 2012. See how the transistors doubled in the same space! :)

Brace yourselves. 'The Future' is no longer the future..its already happened! =) 

Links to more info:
Semiconductor device fabrication - Wikipedia
VLSI Fabrication Technologies - Emanuele Baravelli
VLSI Design, Fabrication steps and layout - Shaahin Hessabi
IC Fabrication Techniques - circuitstoday.com

Tukzer 10000 mAh Power Bank Comprehensive Review

After a lot of research and a budget of around 1000 INR, I decided to buy the Tukzer 10000 mAh power bank. A decision I do not regret at all!

If you want to see the result of that research, check out this post - Which are the best quality, reliable and high output Power Banks and Chargers for USB devices?

This is by far the best power bank for the price of 1.1K INR. I got this in Lightning Deal on amazon.in

Most important points:

• Micro-USB cable included is of a high quality and ensures maximum charging speed.
• It gives a charging current of 1.5A from the 'Tablet' output port and 1A from the 'Phone' output port.
• It takes about 9 hours to fully charge when drained.
• It charges my 3100 mAh Galaxy Note II battery 3 times.

Pros:

1) It is extremely light (about 300g) and compact for 10,000 mAh.

2) High Quality Li-Po batteries ensure maximum efficiency.

2) Overcharging protection circuitry.

3) Shake to see how much charge left on LED indication feature works great!

Cons:

1) Should have had a power ON/OFF button.

2) Does not support pass-through charging, that is, does not charge phone if power-bank is charging.

Verdict:

If you need a stylish power bank of high capacity, high efficiency, light weight and safe, then go for it without second thought! Great bang for the buck!

Which are the best quality, reliable and high output Power Banks and Chargers for USB devices? (India)

I get this question a lot and I recently answered it on Quora too. Here is a more detailed answer with brands chosen among the ocean of other Chinese brands based on their reviews and personal experiences of my friends.

The brands listed here manufacture products for both Android and Apple devices. So happy reading!

Power Banks:

More details on how to choose one and what the 'mAh' rating of power banks means is given on my other post here:
Powerbanks: Which one to buy? What is mAh?

The best Power Banks to my knowledge as of Jan 2016 are:

1) Tukzer - 5200/10000 mAh

Tukzer is possibly the best looking and the best performer among all. It is lightweight and has high Quality Li-Po batteries. Shake the power bank to see the charge level!
You can find a comprehensive review on this one here: Tukzer 10000 mAh Power Bank Review 

2) TP-Link TL-PB - 10400 mAh

Comes with a pouch and in-built flashlight. Slightly heavy. This may not give the full backup capacity as promised, based on some reviews and is 70-80% efficient. 

3) Sony 4700/6100/10000 mAh

Possibly the longest surviving power banks are made by Sony. But they are very expensive.

4) Xiaomi 5600/10400/16000 mAh

Xiaomi is s very well known company for power banks and some of my friends are still using their's since two years. However, these are rarely available as of 2016 in India.

Wall chargers or USB power hubs:

A charger with a 2 Ampere rating will charge your device the fastest. Do not worry, a high current charger will not damage your battery. Your phone can take only a limited amount of current which is decided by the manufacturer. So if it is not manufactured to sink current above 1.5A, it will take only 1.5A even if you connect a 2A charger.

The best wall charger or USB power hub manufacturers for charging your devices as of Jan 2016 would be:

1) Anker (Qualcomm Quick Charge 2.0 18W)

Be careful, online shopping sites are plagued with first-copy duplicates of Samsung and Apple models. Buy from reliable sources.
2) Samsung (2A) 

3) Apple (2.4A)

4) Sony (2A)

5) Nextech (2.4A)

6) QuantumZero (2A)

7) Tukzer (Power Hub 2A+2A+1A+1A)

Charging/data cables:

With a good quality charging brick/hub, you cannot compromise on the quality of the charging cables. Otherwise if the cable offers more resistance or is not made of a good quality material like copper, it will reduce charging speed to a significant extent.

The best charging/data micro-USB cables:

1) Bandridge - 100% Copper cable

2) Tukzer

3) Rock

2015 Tech Writing Achievements

Wishing everyone a Merry Christmas! :) Come 2016, I feel like sharing some of my best achievements in the blogging and tech recommendations world!

1) Blogger
My December 2014 post for fixing 'Thread Stuck in Device Driver' Error, encountered by a huge number of people after Windows 8.1/10 update, was very well received and worked for many people! It has more than 17K views! I was on Cloud 9 after getting that kind of appreciation for working and researching on something from the bottom of my heart.

Here is that answer: FIX 'THREAD STUCK IN DEVICE DRIVER' error for Windows 8/8.1/10

It definitely made my blog shine in 2015!

2) Quora
The following answer was a small achievement for me on Quora. I was awarded the most-viewed writer award for 'Dell' and 'Hewlett Packard' for some time. It was posted on 8th September, 2015 and I held that title for about 3 months after it became well-known.

Here is my answer on Quora: 
Answer on Quora by Nimish Gujarathi to 'Which laptop I should buy Dell or Lenovo or HP?'

The Answer:

If you are stuck between choosing company instead of specs I would say Dell, anytime Dell. Even if it may cost about 5K INR more or less depending on specifications.

My experience of comparison between these three tells me: 

1) Dell is more flexible with qualities like cross compatibility between batteries of different models, (like Latitude and Inspiron have same battery), standard charger port among all Dells so you can share charger of same electrical specifications. HP and Lenovo have their own custom shaped port. 
Analogy: Android with micro-USB which majority had and iPhone 5s with lightning connector which was rare in 2013.

2) Dell is more robust. Drop your HP and Lenovo and they will break like ceramic. I have seen both Dell and Lenovo fall. Screen connector of Lenovo broke and the person was forced to painstakingly use the crippled laptop for another year somehow due to financial issues, as service center could not help and asked for a large sum to change body. Dell however, survived without a scratch.

3) It is fairly obvious that HP is overpricing their products & accessories (HP battery costs about 6-7K INR, Dell battery costs around 2-3K INR) and with the reliability being not commensurate to the price. Dell is reasonably priced and gives most punch for the price.

4) Dell Support is simply amazing. The person sitting behind that toll free help number knows almost everything and gets you out of any situation.

5) Almost all Dell laptops can be customized. I myself could upgrade from 4GB to 8GB RAM. 

6) The performance of Dell is simply amazing. I run heavy softwares like MATLAB and Xilinx as well as high-end games like Battlefield 3 and Mafia II smoothly (Core i7 3632qm coupled with 2GB AMD Radeon HD 7730). The full HD screen is beautiful and sharp bringing out the best quality that the media has to offer. 

7) If you want to force me in telling you issues with Dell I would only speak about battery life. It has reduced from 2.5 hours to 1-1.5 hours in 4 years of use. Happens to all laptops though.

What is 'Class' in SD Memory Cards?

You always have that one friend who will boast about having got a memory card of a high capacity at a cost that is super-cheap in some deal. There is very high chance that, that memory card is of a lower 'Class' than the more expensive ones out there and it may not give him performance.

This post applies to all types of SD (Secure Digital) memory cards, be it micro-SD, mini-SD, SD, SDXC, SDHC and so on.

So to make it very simple:

Class = Speed and Performance

ALWAYS look out for 'class' logo while buying memory cards!

You will see these kind of logos on memory card which signify their class.

Here is an example of how cost differs with class.

Now, the number written in circle, signifies the write speed of the memory card. For example, 4 means minimum 4 MBps writing speed will be ensured! It can go above that, and if it is so, it will be specified on the packaging. Higher the class, higher will be the cost of the memory card.

Question: But Nimish, how is this 'class' significant and how do I choose which class I need?
Answer: Here is a Wikipedia extract.

Source: Speed Class rating of Secure Digital(SD)

Write Speed Significance:
Like many reviews will tell you, if you have a DSLR that has a very high shutter speed, that is, it can capture photos very fast, then you will require a high performance memory card on which they can be quickly stored. Otherwise, your memory will become a limitation and you may not be able to choose a higher shutter speed. In such a case, you might have to choose a minimum class 6 or better yet, class 10.

UHS Speed may be required if you want to shoot 4K video with your camcorder.

Read Speed Significance:
If you have a performance demanding game installed on your Android smart-phone's micro-SD card, no matter how powerful the phone hardware is, your micro-SD card will become a limitation on performance if it does not offer high reading speeds.

For example, if you try to use a class 2 card for installing and playing something like Asphalt on a Galaxy Note II, it will definitely lag. But it will not lag if you use a class 6 or a class 10 card. Your general phone performance will also be affected depending on the class of the memory card, if you choose to install applications on the memory card.

So in conclusion, don't be fooled if someone offers a hard-to-believe dirt cheap price on a high capacity memory card and check the class rating on it first.