Prelude:

Until the late 19th century, people produced their own power. They connected their horse, windmill or water wheel to run their own machines. However, in the late 19th century, power plants were invented to produce large amounts of power in a single unit and transmit to every home. Now, you no longer need to run your own power generator like in the picture above or move your muscles to grind stuff. You could just flick a switch.

Cloud computing is doing to computing what power plants did to power production 150 years ago. Just like the farmers above, we are still running big computers at our home - to store data, run software etc. Your PC is as powerful as the ones that sent a spaceship to the moon 45 years ago. Why do you need such a powerful computer at your home? What if you could move all these computers to some remote location and through a wire just access relevant data at the right time to your iPad or phone?

The revolution in electric power production changed the world. In the same way, this change in computing could produce a big change in the way thing work. 

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What is cloud computing?

To start simply, think of cloud computing as using someone else's computer. For instance, if you are using Gmail, you are storing your mails on Google's cloud. Your emails are not in your local PC, but in Google's hard disc.  If you are storing files on Dropbox, you are keeping your files on Dropbox' cloud. Or think of what happens when you play a video on Youtube. All the movie files are in Google's computers while you are able to watch them 1000s of miles away from it.  In short, a cloud in this case refers to a group of connected machines with storage drives and processors that becomes an extension of your local computer.

Each of these companies have large data centers that look like factories with millions of computers kept in endless racks. Look at one of Google's data centers below [each blue light is a computer]. It could consume as much power as a small hydroelectric power station could produce. 

Millions and millions of such computers are kept in the data centers where your emails are stored and various processes run - like when you search for something on Google. Like Google, all major companies run their own data centers - Microsoft, Yahoo, Apple, Amazon all have their own stack of computers in such "factories".

Why is there a big talk of cloud?

Previously, companies and consumers just bought their own computers and maintained it. You will use your PC to store all your songs, videos, files etc. In the same way, your company will maintain its own servers for storing all the company's documents. 

This process is inefficient as maintaining computers is expensive. You need to do all the hardwork like periodically buy new computers, update the OS, secure the system and back data up periodically. 

Do you produce your own electricity or farm your own food? So, why do you need to buy your own computers, when all you need is information?

Just like a power plant takes care of all the machines to just help you final output - electric power - a cloud computing company takes care of all physical computers so that in the end I just need my information. This makes a huge improvement to businesses. In the startup I cofounded, I use 8 servers and none of them lived in my office. These were all in Amazon's datacenters and they just "rented" these computers on an hourly basis. I could store information and run all the processes, while they care about buying hardware and taking care of security.

This is fundamentally altering the way in which computing works. A range of new companies is coming to help companies manage their data without having to buy hardware for it. 

In what ways is a cloud relevant to you:

1. Store information: Previously, we used to just save files on our local machine. However, if you had to share with other people, we had to do clunky things like zipping it & sending it via email. Now, we could just store these files in the "cloud" [aka the computers of Dropbox] and send the other person just the link. Even if your PC dies, you can always access the data from Dropbox. Enterprises generate massive amounts of data and now many of them are using the cloud as it reduces their need to buy massive servers.
2. Access content: It helps you use content without storing anything on local computer. For instance, when you play a video on Youtube, your harddisk space is not affected at all as the video exist within one of Google's data centers above.
3. Run processes: A computer is a machine that computes. For instance, at my startup Zingfin we had to collect millions of tweets a day and run mathematical calculations to find out which of the tweets were saying negative about a particular company. That software I wrote lived in a computer somewhere in Amazon's Virginia datacenter and kept running. All I had to do was pay Amazon per hour. 
4. Access on demand: Here is the kicker. Does your power usage vary? Most likely yes. When you are out of home, you won't need much power compared to when you are having your AC, Vacuum, Fridge and Oven on. When our power consumption increases, the consumers don't need to spend buy a new power plant, but just pay for the increased usage at that time. The power utility intelligently manages the load. In the same way, with cloud computing organizations can get 100 computers on demand when they need it and pay for only usage. This is why cloud computing is getting so much attention nowadays.

Types of cloud

1. If the cloud [aka a bunch of computers in a datacenter] is open to all public, then it is a public cloud. For instance, Gmail is open to almost anyone and your emails might be stored in the same harddisc in a Google's datacenter as mine. This is very efficient as Google could save as many emails as a hard disc could hold and then when it fills use the next hard disc. Because of the high level of resource utilization,  this is typically the cheapest kind of cloud access.
2. Many companies are leery of having their data sit with other people's data on the same machine. If you are the CIA, you might not like your data files stored in the same hard disc as Russia's KGB. You might want dedicated computers that stores only your files, even if the hard disc is mostly empty. If the cloud is made for a specific company then it is termed a private cloud. Even if Google or other data providers gurantee security and privacy, it is not sufficient to big enterprises or hospitals. In a private cloud, all the connected machines in a unit are dedicated to one company and it is not open to anyone else.

Look at some pics of awesome datacenters:
Stunning Photos Of Google's Massive Data Centers 

Some of my posts on Cloud Computing: CloudTweaks.com
Balaji Viswanathan

Something in line with the following conversation should help in explaining the concept to him. :)

Y: You, C: Child

Ask the 10 year old: "If you had only 10 rupee notes, and wanted to buy a chocolate of Rs. 20 what would you do?"
Child will say - "Give the shopkeeper 2 notes"

Y: "Let's go to another shop. What would you do if a better chocolate costs Rs. 50 there?"
C: "I will give shopkeeper 5 notes"

Y: "Good, There's another shop called XYZ which sells the best chocolate at Rs. 500 and accepts nothing but Rs. 100 notes. It is indeed an awesome chocolate that you will really like. What would you do then?"
C: "Give him 50 notes"

Y: "Remember the shopkeeper accepts only Rs. 100 notes?'"
C: "But I will give him the same amount of money!!"

Y: "But he uses a different system, he runs his shop only on 100 Rupee notes. But you have only 10 rupee notes. Are they of any value if you want to do business with the shop?"
C: "No. I might have to take 5*100 rupee notes from someone and give him 50 notes in return"

Y: "Good!! Let us say a man is standing outside the shop offering 100 rupee notes in exchange for 10 rupee notes..then?"
C: "Wow!! I will give 50 notes to him, and take 5*100-rupee notes"

Y: What if the person says 'Everybody seems to like the chocolate here. Everybody wants 100 rupee notes. I want 60 notes for 5*100 notes'. 
Now C starts thinking. 

Y: You really want the chocolate. Meanwhile another person comes and tries to buy his 100 rupee notes. If you do not buy his note quickly - he might ask for even more notes because, many people want to buy his notes

Y: "Did the value of the chocolate change?"
C: "No"

Y: "Did you have less money?"
C: "No"

Y: "Then what was the problem?"
C: "The shopkeeper wants only 100 Rupee notes!!! :( "

Y: "But finally did you end up paying more than 500 rupees for a 500 rupee chocolate?"
C: "yes!!! :("

Y: "Why? The chocolate price never changed!"
C: "The chocolate price remained the same. But the price of the 100 rupee note was more!!! :( "

Y: "That is what happens. The shop is USA. Lets call the 100 rupee note as theDollar. Other shops are India. They accept your 10 rupee note. The 'value' lies in the thing. Money is just a medium of exchange. So its value comes from its 'level of acceptance' by people. The chocolate is the same value, but is available only in USA. If you want to do business with him, you need to give him whatever note he wants. He accepts only Dollars. Your 10 rupee note has no value - although you have as many as you want. So you have to go to somebody who has dollars. When you buy the dollar, the price depends  on how high the demand for the dollar is. It has nothing to do with the actual value of the chocolate you are buying. What happens if more and more people want the dollar?"

C: "I will have to pay more and more rupees for the same dollar" (Exchange rate)

You end with: "So when we say $1 is equal to INR 60, it means that everybody wants to buy dollars. Actually, if you want to do business with any FOREIGN country, the rule is that you should use dollars. So the price has become very high. You have to pay 60 rupees to just buy 1 dollar."

This  will explain the exchange rate, forex trading and the dollar standard concepts. But the curiosity might continue.... 

C: "OK, but why should everybody use the dollar? What if somebody is OK to take my 10 rupee note?"
Y: "Then ugly things happen. You will understand only when you grow up"

Also read My answer to How would you explain the concept of inflation to a 10 year old?
Vijayraj Kamat

Do you find that using the word "VERY" is making your answer lose its grace and even ruining your creativity. It happens most of the time to me.

'Very' is the most useless word in the English language and can always come out. More than useless, it is treacherous because it invariably weakens what it is intended to strengthen. ~Florence King

So avoid using the word ‘very’ because it’s lazy. A man is not very tired, he is exhausted. Don’t use very sad, use morose. Language was invented for one reason, boys - to woo women - and, in that endeavor, laziness will not do. It also won’t do in your essays. ~N.H. Kleinbaum

So, its better to follow this table - 

I hope this took less than five minutes .

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If you have half a more minute to spare then, have a quick look at some other words which are better to express some feelings in an essay/answer . 

And, also while writing, make sure that your writing is confident enough to convey its message to the reader .

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UPDATE : Whoa! An astounding response to this answer, I am highly honored. 

Some synonyms for garnishing your answers ( better make a sticky note for it or add this answer to your Reading List . ) 

Amazing — incredible, unbelievable, improbable, fabulous, wonderful, fantastic, astonishing, astounding, extraordinary
Anger — enrage, infuriate, arouse, nettle, exasperate, inflame, madden
Angry — mad, furious, enraged, excited, wrathful, indignant, exasperated, aroused, inflamed

Answer — reply, respond, retort, acknowledge
Ask- — question, inquire of, seek information from, put a question to, demand, request, expect, inquire, query, interrogate, examine, quiz
Awful — dreadful, terrible, abominable, bad, poor, unpleasant
Bad — evil, immoral, wicked, corrupt, sinful, depraved, rotten, contaminated, spoiled, tainted, harmful, injurious, unfavorable, defective, inferior, imperfect, substandard, faulty, improper, inappropriate, unsuitable, disagreeable, unpleasant, cross, nasty, unfriendly, irascible, horrible, atrocious, outrageous, scandalous, infamous, wrong, noxious, sinister, putrid, snide, deplorable, dismal, gross, heinous, nefarious, base, obnoxious, detestable, despicable, contemptible, foul, rank, ghastly, execrable
Beautiful — pretty, lovely, handsome, attractive, gorgeous, dazzling, splendid, magnificent, comely, fair, ravishing, graceful, elegant, fine, exquisite, aesthetic, pleasing, shapely, delicate, stunning, glorious, heavenly, resplendent, radiant, glowing, blooming, sparkling
Begin — start, open, launch, initiate, commence, inaugurate, originate
Big — enormous, huge, immense, gigantic, vast, colossal, gargantuan, large, sizable, grand, great, tall, substantial, mammoth, astronomical, ample, broad, expansive, spacious, stout, tremendous, titanic, mountainous
Brave — courageous, fearless, dauntless, intrepid, plucky, daring, heroic, valorous, audacious, bold, gallant, valiant, doughty, mettlesome
Break — fracture, rupture, shatter, smash, wreck, crash, demolish, atomize
Bright — shining, shiny, gleaming, brilliant, sparkling, shimmering, radiant, vivid, colorful, lustrous, luminous, incandescent, intelligent, knowing, quick-witted, smart, intellectual
Calm — quiet, peaceful, still, tranquil, mild, serene, smooth, composed, collected, unruffled, level-headed, unexcited, detached, aloof
Come — approach, advance, near, arrive, reach
Cool — chilly, cold, frosty, wintry, icy, frigid
Crooked — bent, twisted, curved, hooked, zigzag
Cry — shout, yell, yowl, scream, roar, bellow, weep, wail, sob, bawl
Cut — gash, slash, prick, nick, sever, slice, carve, cleave, slit, chop, crop, lop, reduce
Dangerous — perilous, hazardous, risky, uncertain, unsafe
Dark — shadowy, unlit, murky, gloomy, dim, dusky, shaded, sunless, black, dismal, sad
Decide — determine, settle, choose, resolve
Definite — certain, sure, positive, determined, clear, distinct, obvious
Delicious — savory, delectable, appetizing, luscious, scrumptious, palatable, delightful, enjoyable, toothsome, exquisite
Describe — portray, characterize, picture, narrate, relate, recount, represent, report, record
Destroy — ruin, demolish, raze, waste, kill, slay, end, extinguish
Difference — disagreement, inequity, contrast, dissimilarity, incompatibility
Do — execute, enact, carry out, finish, conclude, effect, accomplish, achieve, attain
Dull — boring, tiring„ tiresome, uninteresting, slow, dumb, stupid, unimaginative, lifeless, dead, insensible, tedious, wearisome, listless, expressionless, plain, monotonous, humdrum, dreary
Eager — keen, fervent, enthusiastic, involved, interested, alive to
End — stop, finish, terminate, conclude, close, halt, cessation, discontinuance
Enjoy — appreciate, delight in, be pleased, indulge in, luxuriate in, bask in, relish, devour, savor, like
Explain — elaborate, clarify, define, interpret, justify, account for
Fair — just, impartial, unbiased, objective, unprejudiced, honest
Fall — drop, descend, plunge, topple, tumble
False — fake, fraudulent, counterfeit, spurious, untrue, unfounded, erroneous, deceptive, groundless, fallacious
Famous — well-known, renowned, celebrated, famed, eminent, illustrious, distinguished, noted, notorious
Fast — quick, rapid, speedy, fleet, hasty, snappy, mercurial, swiftly, rapidly, quickly, snappily, speedily, lickety-split, posthaste, hastily, expeditiously, like a flash
Fat — stout, corpulent, fleshy, beefy, paunchy, plump, full, rotund, tubby, pudgy, chubby, chunky, burly, bulky, elephantine
Fear — fright, dread, terror, alarm, dismay, anxiety, scare, awe, horror, panic, apprehension
Fly — soar, hover, flit, wing, flee, waft, glide, coast, skim, sail, cruise
Funny — humorous, amusing, droll, comic, comical, laughable, silly
Get — acquire, obtain, secure, procure, gain, fetch, find, score, accumulate, win, earn, rep, catch, net, bag, derive, collect, gather, glean, pick up, accept, come by, regain, salvage
Go — recede, depart, fade, disappear, move, travel, proceed
Good — excellent, fine, superior, wonderful, marvelous, qualified, suited, suitable, apt, proper, capable, generous, kindly, friendly, gracious, obliging, pleasant, agreeable, pleasurable, satisfactory, well-behaved, obedient, honorable, reliable, trustworthy, safe, favorable, profitable, advantageous, righteous, expedient, helpful, valid, genuine, ample, salubrious, estimable, beneficial, splendid, great, noble, worthy, first-rate, top-notch, grand, sterling, superb, respectable, edifying
Great — noteworthy, worthy, distinguished, remarkable, grand, considerable, powerful, much, mighty
Gross — improper, rude, coarse, indecent, crude, vulgar, outrageous, extreme, grievous, shameful, uncouth, obscene, low
Happy — pleased, contented, satisfied, delighted, elated, joyful, cheerful, ecstatic, jubilant, gay, tickled, gratified, glad, blissful, overjoyed
Hate — despise, loathe, detest, abhor, disfavor, dislike, disapprove, abominate
Have — hold, possess, own, contain, acquire, gain, maintain, believe, bear, beget, occupy, absorb, fill, enjoy
Help — aid, assist, support, encourage, back, wait on, attend, serve, relieve, succor, benefit, befriend, abet
Hide — conceal, cover, mask, cloak, camouflage, screen, shroud, veil
Hurry — rush, run, speed, race, hasten, urge, accelerate, bustle
Hurt — damage, harm, injure, wound, distress, afflict, pain
Idea — thought, concept, conception, notion, understanding, opinion, plan, view, belief
Important — necessary, vital, critical, indispensable, valuable, essential, significant, primary, principal, considerable, famous, distinguished, notable, well-known
Interesting — fascinating, engaging, sharp, keen, bright, intelligent, animated, spirited, attractive, inviting, intriguing, provocative, though-provoking, challenging, inspiring, involving, moving, titillating, tantalizing, exciting, entertaining, piquant, lively, racy, spicy, engrossing, absorbing, consuming, gripping, arresting, enthralling, spellbinding, curious, captivating, enchanting, bewitching, appealing
Keep — hold, retain, withhold, preserve, maintain, sustain, support
Kill — slay, execute, assassinate, murder, destroy, cancel, abolish
Lazy — indolent, slothful, idle, inactive, sluggish
Little — tiny, small, diminutive, shrimp, runt, miniature, puny, exiguous, dinky, cramped, limited, itsy-bitsy, microscopic, slight, petite, minute
Look — gaze, see, glance, watch, survey, study, seek, search for, peek, peep, glimpse, stare, contemplate, examine, gape, ogle, scrutinize, inspect, leer, behold, observe, view, witness, perceive, spy, sight, discover, notice, recognize, peer, eye, gawk, peruse, explore
Love — like, admire, esteem, fancy, care for, cherish, adore, treasure, worship, appreciate, savor
Make — create, originate, invent, beget, form, construct, design, fabricate, manufacture, produce, build, develop, do, effect, execute, compose, perform, accomplish, earn, gain, obtain, acquire, get
Mark — label, tag, price, ticket, impress, effect, trace, imprint, stamp, brand, sign, note, heed, notice, designate
Mischievous — prankish, playful, naughty, roguish, waggish, impish, sportive
Move — plod, go, creep, crawl, inch, poke, drag, toddle, shuffle, trot, dawdle, walk, traipse, mosey, jog, plug, trudge, slump, lumber, trail, lag, run, sprint, trip, bound, hotfoot, high-tail, streak, stride, tear, breeze, whisk, rush, dash, dart, bolt, fling, scamper, scurry, skedaddle, scoot, scuttle, scramble, race, chase, hasten, hurry, hump, gallop, lope, accelerate, stir, budge, travel, wander, roam, journey, trek, ride, spin, slip, glide, slide, slither, coast, flow, sail, saunter, hobble, amble, stagger, paddle, slouch, prance, straggle, meander, perambulate, waddle, wobble, pace, swagger, promenade, lunge
Moody — temperamental, changeable, short-tempered, glum, morose, sullen, mopish, irritable, testy, peevish, fretful, spiteful, sulky, touchy
Neat — clean, orderly, tidy, trim, dapper, natty, smart, elegant, well-organized, super, desirable, spruce, shipshape, well-kept, shapely
New — fresh, unique, original, unusual, novel, modern, current, recent
Old — feeble, frail, ancient, weak, aged, used, worn, dilapidated, ragged, faded, broken-down, former, old-fashioned, outmoded, passe, veteran, mature, venerable, primitive, traditional, archaic, conventional, customary, stale, musty, obsolete, extinct
Part — portion, share, piece, allotment, section, fraction, fragment
Place — space, area, spot, plot, region, location, situation, position, residence, dwelling, set, site, station, status, state
Plan — plot, scheme, design, draw, map, diagram, procedure, arrangement, intention, device, contrivance, method, way, blueprint
Popular — well-liked, approved, accepted, favorite, celebrated, common, current
Predicament — quandary, dilemma, pickle, problem, plight, spot, scrape, jam
Put — place, set, attach, establish, assign, keep, save, set aside, effect, achieve, do, build
Quiet — silent, still, soundless, mute, tranquil, peaceful, calm, restful
Right — correct, accurate, factual, true, good, just, honest, upright, lawful, moral, proper, suitable, apt, legal, fair
Run — race, speed, hurry, hasten, sprint, dash, rush, escape, elope, flee
Say/Tell — inform, notify, advise, relate, recount, narrate, explain, reveal, disclose, divulge, declare, command, order, bid, enlighten, instruct, insist, teach, train, direct, issue, remark, converse, speak, affirm, suppose, utter, negate, express, verbalize, voice, articulate, pronounce, deliver, convey, impart, assert, state, allege, mutter, mumble, whisper, sigh, exclaim, yell, sing, yelp, snarl, hiss, grunt, snort, roar, bellow, thunder, boom, scream, shriek, screech, squawk, whine, philosophize, stammer, stutter, lisp, drawl, jabber, protest, announce, swear, vow, content, assure, deny, dispute
Scared — afraid, frightened, alarmed, terrified, panicked, fearful, unnerved, insecure, timid, shy, skittish, jumpy, disquieted, worried, vexed, troubled, disturbed, horrified, terrorized, shocked, petrified, haunted, timorous, shrinking, tremulous, stupefied, paralyzed, stunned, apprehensive
Show — display, exhibit, present, note, point to, indicate, explain, reveal, prove, demonstrate, expose
Slow — unhurried, gradual, leisurely, late, behind, tedious, slack
Stop — cease, halt, stay, pause, discontinue, conclude, end, finish, quit
Story — tale, myth, legend, fable, yarn, account, narrative, chronicle, epic, sage, anecdote, record, memoir
Strange — odd, peculiar, unusual, unfamiliar, uncommon, queer, weird, outlandish, curious, unique, exclusive, irregular
Take — hold, catch, seize, grasp, win, capture, acquire, pick, choose, select, prefer, remove, steal, lift, rob, engage, bewitch, purchase, buy, retract, recall, assume, occupy, consume
Tell — disclose, reveal, show, expose, uncover, relate, narrate, inform, advise, explain, divulge, declare, command, order, bid, recount, repeat
Think — judge, deem, assume, believe, consider, contemplate, reflect, mediate
Trouble — distress, anguish, anxiety, worry, wretchedness, pain, danger, peril, disaster, grief, misfortune, difficulty, concern, pains, inconvenience, exertion, effort
True — accurate, right, proper, precise, exact, valid, genuine, real, actual, trusty, steady, loyal, dependable, sincere, staunch
Ugly — hideous, frightful, frightening, shocking, horrible, unpleasant, monstrous, terrifying, gross, grisly, ghastly, horrid, unsightly, plain, homely, evil, repulsive, repugnant, gruesome
Unhappy — miserable, uncomfortable, wretched, heart-broken, unfortunate, poor, downhearted, sorrowful, depressed, dejected, melancholy, glum, gloomy, dismal, discouraged, sad
Use — employ, utilize, exhaust, spend, expend, consume, exercise
Wrong — incorrect, inaccurate, mistaken, erroneous, improper, unsuitable

Source : StumbleUpon

If you want more some daily doses of such hacks then please visit my blog -
Learn within few minutes Hacks.
Kaushik Kulkarni

• Whenever you're curious about something, write it down. This way, whenever you're bored you'll have an entire list of things to learn about.
• You can tell if you're dreaming or not by looking around for clocks, clocks will never be in dreams.
• If you don't know whether to write "affect" or "effect", use the word "impact" instead.
• "Having sex with any of your ex isn't cheating. These are what we call "retirement benefits"
• If your girlfriend catches you looking at another woman, turn to her and say “I’m glad you don’t dress like that.
• Try not to say anything negative about anyone for a week, month, or year. Watch what happens to your life.
• Want to lose weight? Don't eat anything 4 hours before you go to bed. It makes a huge difference.
• If you realized how powerful your thoughts are, you would never think a negative thought.
• No one wants to hear you talk about your health, your dreams, your diet, or your money

Jimeet Shah

Time to decode the Barcode!

Let's start from something which you would be already knowing. All Barcodes look similar - atleast when viewed from distance. They have the same alternating black and white lines (always). Plus there is one more similarity - there are exactly 95 lines of those. 

So let's build on from here. There are 95 columns evenly spaced. Some columns appear thicker when a group of columns are of same color, both black and white. See the top of the figure below

​


Next, when the laser light falls on these set of parallel lines, the white lines reflect most of the light while black lines don't. Now computers can understand only two numbers either zero or one. So it treats no light lines as ones and all light lines as zero - ya it is a bit less intuitive, but it is.

Time to go into more detail now.

​
(image source - Wikipedia )

The first line reflects none of the light (or very less light) - Hence assigned the digit 1. The next line reflects almost all light - hence assigned 0. In the same manner all columns are assigned the numbers. Total assignations  - 95. Note these numbers are different from the one actually put below. After this, these 95 numbers are grouped in 15 different sections. 12 of these sections are used for the actual visible numbers and rest 3 acts as guards - Left Guard, center guard and right guard. You can see that in each bar code the left, right and the center are similar.

The patterns for the left side code are shown below -

​

The pattern for the right side is similar except that it has even number of 1s. This helps the computer to figure out which side is left/right, in case the product has been turned upside down! There is one more check for this. All the codes for the left side begin with a 0 while for the right side they begin with 1, leaving the guards.

​


Each of the above 6 vacant spaces on either side represents the numbers you see on the bar code. 

Okay now we have got the numbers, what do they mean actually?

1. The very first number decides the type of product - Standard, weighted items, pharmacy, coupons etc.

2. The next 5 set of numbers tells who the manufacturer of the product is.

3. The next 5 set of numbers tells the product code.

4. Finally the final digit, is called Modulo check character. It is used for error checking. It is an important number and functioning is explained below.

To get the Modulo check character

Add all the digits at odd places. There are 11 digits (leaving the Modulo number)

So for the above figure it is 

0+6+0+2+1+5 = 14 : Multiply it by 3  to get 42

Now add the even digits: 3 +0+0+9+4 = 16

Add both: 42 + 16 = 58.

Now the modulo check number is got by subtracting this from the next higher multiple of 10. Here 60 - 58 = 2 --> The Modulo number.

This is how the scanner verifies whether the code is correct or not.

Now does barcodes have information on price?

Yes, but not directly. After scanning the barcodes, the scanner sends
the code to a central computer and from there it fetches up the price. By this the price of the product can be changed accordingly at the central Point of Sale computer.

Some interesting facts.

The bar codes were originated from the Morse code. By extending the dots and dashes vertically.

Before putting it on the packets, at one point of time, Barcodes were put inside the packet! After that it was found to be much easier to print it on it.

The first scanning of bar code took on Wrigleys' chewing gum.

There are over a hundred of different bar code types invented, however, only a half-dozen are used regularly.
Raj Arjit