The working of an optical drive!

Nowadays, all systems come with DVD burners. Due to this, the use of cassettes has become obsolete since users prefer using DVD’s for storing audio and video files as well as other data. Let’s take a look at how DVD burners actually write data onto a DVD.

We are all aware of what an optical drive is all about as well as the laser which is the most important part of an optical drive that reads or writes data into a DVD. In this article, we take a look at the innards of a DVD as well as how data is read and written using the laser.

THE BUMPS AND FLAT AREAS ON A NORMAL DISK

All data that is stored on a disk in the digital form i.e. 0s and 1s. In a normal CD, these 0s and 1s are represented by bumps and flat areas on the disc’s surface. For reading information, a laser is passed over the track by the CD player. When the laser is passed on a flat area, the beam directly reflects to the optical sensor. The CD player will then recognize this as 1. On the other hand, when the beam is passed over a bump, light is bounced away from the sensor and the player recognizes this as 0.

Starting at the center of the CD, bumps are arranged in a spiral manner. The laser assembly is moved in an outward direction while the disk spins in the CD player. The bumps move at a higher speed near the outer edge if the CD than they move near center of the CD. As the laser assembly moves outward, the CD player slows the spinning speed in order to keep all bumps on the CD moving at the same rate.

ABOUT A DVD-RW DISK

DVD-RW discs are devoid of bumps and flat areas. Instead of these, DVD-RW’s have a reflective metal layer. This layer lies on top of a layer of photosensitive dye.

When there is no data on the disc, the dye is translucent, meaning that light can shine through and reflect off the surface. But when an attempt to write data on a disk is made, due to the heat, the dye turns opaque, i.e. the points are darkened so that the light can’t pass through.

By leaving some areas on the disk translucent and darkening particular points, a digital pattern is created that can be read by a standard DVD player. Hence it acts as a standard DVD though it’s devoid of bumps and flats.

Now that we know some of the basics, let’s further see how the DVD burner can read and write data on a disk.

So far we know that DVD burners darken certain areas of a disc for recording digital data that can be read by a normal DVD player. The burning system is quite precise since data must be encoded properly onto the disc. Actually, the DVD burner works in a similar way like a normal DVD player, except that it contains a ‘write’ laser. The write laser interacts with the disk in a different manner. It can alter the surface of the disk i.e. it can do more than just bounce off light from it. It functions in a similar manner as the read laser i.e. it moves in an outward direction while the disk spins. The bottom layer which is made up of plastic, contains grooves that guides the laser to the correct path accordingly. By making fine adjustments and measuring the speed, the laser assembly makes sure that the burner keeps the laser running at a constant speed. Finally, for recording data, the DVD burner switches the writer laser on and off in synchronization with the 0 and 1 pattern. The laser will darken an area of a disc to encode a 0 or make it translucent to encode a 1.

Stock Market Cycles Explained! (The basics)

Stock Markets move up and down in recurring cycles. A prolonged rise in stock prices is known as a bull run while a consistent decline is called a bear market. These are different from short-lived upward or downward “corrections” in stock prices. Typically, a bull run or a bear market means at least a 20% change in the index value. Nobody can accurately predict stock market movements, but they can be explained. Here’s what moves the stock markets.

Bull Markets:

Bullishness in the markets can be the result of an economic boom which in turn fuels optimism among investors. The stock markets around the world witnessed the longest bull run during the past five years giving spectacular annualised returns of nearly 50%.

Indicators of a Bull Run:

• Rising corporate earnings
• Low inflation
• Low interest rates
• High fund flows and liquidity
• Increased investor interest

Bear Phases:

Bear phases occur in times of an economic downturn and when there is all-round pessimism. Unlike a correction, a bear market is marked by a consistent fall in stock prices over a long period of time. The New York Stock Exchange and markets of the world are currently in bear phase since the beginning of this year. The markets have lost almost 50%.

Indicators of a Bear Phase:

• Falling corporate earnings
• Rising inflation
• High or rising interest rates
• High fund outflows and liquidity crunch
• Low investor interest

Selling Short

• Bearish markets and falling stock prices don’t always mean losses. You can also profit from falling prices if you use the right strategy and are able to take quick decisions.
• The most common bear market strategy is short selling-or selling shares you do not own in the expectation that the price will fall. When the price falls, you buy back the shares at a lower price.
• Buying back shares to square a position is called short covering. The difference in the price is your profit. Of course, this is risky gambit and can result in a loss if the price rises after you sell.

How Selling Short Works

Suppose you short sell 500 shares of a company at a price of 10$ each. You are expecting the price to fall to 8$. Then according to the table below:

500 shares short sold at $10	Scenario 1: The share price falls	Scenario 2: The share price rises
Stock price	8	11
Difference from your selling price	-2	+1
What you pay to buy back shares	4,000	5500
Your profit (or loss)	1,000	-500

All figures in $

Keep In Mind

• If you are unable to square short selling, the exchange buys shares in an auction and gives them to the buyer. That can lead to losses if share price is higher.
• Discipline is important. Buy back shares when the target price is reached. Similarly, set a strict target to cut your losses and buy back if the price starts rising.
• Don’t wait till the fag end of the session to buy back. Short covering can push up the price of a share as short sellers scramble to buy back.
• Too much short selling can cause a share to be oversold. That is actually a bullish signal as short covering may cause the price of the share to go up.

Stay-at-home Careers!

There’s much to be said for working from home – no traffic jams, no need to leave home early, no bickering with auto-drivers, no office politics…If you have the discipline to dedicate a few hours every day to work, there are plenty of opportunities to earn from home. Some might involve a little travel, but it’s not a daily affair. Be prepared to earn a little less- but the quality of life should make up for the loss of income. Take a look at some options for home-birds.

1. Online Tutoring: You can earn few thousand dollars a month if you’re a qualified teacher or a professor with computer and communication skills. The subjects in demand these days are Mathematics, French, Physics, Statistics, Chemistry and Biology. The advantage is that you can teach part-time (4 hours a day) or full time (9 hours).
2. Placement Agency: If you network, you can earn above 3,000$ per assignment. Many booming sectors in the economy, particularly IT, ITES, insurance, retail and banking, have manpower scarcity. If you tie up with institutes to organize their campus placements or get database of people looking for jobs and help organizations find the right people, you can make a fat packet.
3. Resale: Buy cheap, mark up the prices, make a profit. Depending on what you decide to sell (and your neighbourhood), you can make anything above 1,000$ per month. And the buying need not be a problem; frequent auctions, garage sales and sales by embassies or large companies can get you almost anything for half the value.
4. Wrap it: Offer a gift-wrapping service, either in association with neighbourhood retailer or on your own. You can earn above 1,000$ per month, depending on the demand and your offering.
5. Event planning: It is a good business idea especially if you manage everything. All the extras such as invitations, banners and balloons can be prepared at home. Networking with the business community can help you get a lot of work.You could make above 3,000$ for every event.
6. Blogging: Well almost all of you are bloggers on hubpages but if you aren’t then sign up and start writing quality hubs. If you draw traffic and clicks you can make a few hundred dollars every month. Some people have received a check of 1,000$. Make sure you have a google adsense account and enter the ID in affiliate section.

PC for entertainment!

We conducted a straw poll among friends to find out what they used their home computers for most of the time. Work, we fondly thought. But no. Some used them to download and organize music, others played games, and almost all watched movies. If this lot represents a larger universe (and chances are that they do), it’s the entertainment aspect of a PC that seems to be the most coveted and appreciated. So here’s a look at all that you need to turn your existing machine into a media centre – or what you’ll need to look for if you’re in the market for a new computer.

1. The Heart Of A PC…. Is its processor. And this is what lets you watch the latest videos on one window, even as you have some six browser tabs, a couple of spreadsheets and image files open. The speed of the processor determines, among other things, how fast you can switch between windows when the resident slave-driver appears on the horizon. So, if you want to be able to do more than one thing at a time without waiting forever, you need a dual core processor. Even better, splurge on a quad core, and you’ll not need to upgrade for a while.
2. Memory Matters: If you’re one of those waiting eagerly for The Kite Runner to be released, you’ll either have to have immense patience or download an illegal version of the movie. Unless you want all other work to come to a screeching halt for the two or more hours it takes to download the movie, increase the memory of your computer to at least 2 GB, ideally 4 GB. With an 80 GB iPod, 16 GB in your digicam, and who knows how much in your mobile phone, you deserve to have a hard drive of 320 GB or so. After that, as Google says, you’ll never need to delete another file.
3. What You See: Whether you’re trying to get the essence of Truffaut or laughing your guts out at Mr Bean, it helps to watch movies on a large screen. Thankfully, TFT and LCD monitors are getting cheaper and better. A 14”-15” wide screen for a laptop and a 17”-19” screen for a desktop should do the trick – and will also help prevent eye strain.
4. Sound And Light: So, you’ve created a brilliant playlist of indie music – Andrew Bird, The Automatic, The Moldy Peaches and Vampire Weekend – and want to listen to it in the car. With the right accessories, this should be a breeze. After all, it’s a pretty sad computer that comes without a CD or DVD writer. If yours doesn’t include these devices, get one installed. You can’t go too wrong with LightScribe DVD drives and writers.
5. ADD-ONS Count: Gheorghe Zamfir will sound like he’s playing a penny-whistle if you listen to music on those tinny computer speakers. Even if you aren’t a hard-core audiophile, invest in a decent set of Creative speakers. The 2.1 system is good for most of us; if you’re a music snob, blow up a small fortune on the 7.1 system. Add an iBall webcam and a Logitech or Trenty microphone and you’re all set.
6. All About Software: Even dedicated Windows/Microsoft-bashers have nothing but good things to say about Windows Media Centre. It’s seen as the best way to seamlessly integrate different media: video, music, photos, text and the like. However, this is not available as an independent application – it comes as a part of the Windows XP Media Centre edition, or bundled with Vista Home Premium and Vista Ultimate. So, if you want the Media Centre, look for one of these operating systems. With a little smart wiring, you can connect the computer to your TV, Xbox and home theatre system.