The Internet

Computers and

the Internet

Part II

Internet Speed Limits

One of the major complaints about the Internet, of course, is how slow it can be. So, first we'll examine the things that limit speed and give you some pointers on how you can speed things up — especially when "surfing the net" from home.

The CPU

The speed of your computer's CPU (central processing unit — a computer chip that's the heart of your computer) will to a large extent determine the speed of software operations.

The latest computer CPUs operate at more than 3 GHz (gigahertz, or billion operations per second).

Every six months or so the CPU chip makers are able to develop a faster CPU. This is one of the reasons computers quickly become obsolete. Part of a motherboard (the main circuit board area of the computer) is shown above.

Although there is a definite element of ego behind having the "fastest computer on the block," there is also a practical element. As computer programs become more complex, computer resources — especially speed — must also advance, to keep pace.

RAM

CPU speed is only one of several factors that determine how fast things will happen in your computer. The amount of memory your computer has is also important.

Most computers today have at least 525 megs (megabits) of RAM (random-access memory). When your computer boots up (starts), needed programs are loaded into RAM, where information can be quickly accessed.

RAM is volatile memory because all of the information in RAM disappears when the power to your computer shuts off. This, of course, includes whatever data that you may have been reading or working on that wasn't saved on a hard or floppy disk.

The hard drive in your computer represents nonvolatile memory, or information that is recorded on a medium — in this case a hard drive — that stays there once the power to your computer is shut off. Thus, any information you want available the next time you boot up your computer must be saved on a disk drive.

The speed of RAM (how quickly it can absorb and transmit information) is also important to computer speed. RAM speed is measured in nanoseconds (ns), or billionths of a second. In terms of speed, the smaller the number, the better.

A typical computer chip is shown on the right. As computer programs get bigger and more complex, there is also a need to add more computer RAM so that things won't slow down.

Keep in mind that program and data information that won't fit into RAM when the computer boots up must be read from the hard drive, which is a slower process than using RAM for the same purpose. Thus, the more RAM the better.

Hard Disks

Hard disks or hard drives were invented by IBM in 1956. The first one could only hold about 5MB of data — by today's standards not even enough to hold a respectable word processing program. Even so, IBM rented their hard drive to users for $3,100.00 a month.

Using that cost ratio as a standard, one of today's (very small) computer hard drives would sell for hundreds of millions of dollars. (This has been one of the few things in life where you have been able to get more for less money on almost a monthly basis.)

A cutaway view of a hard drive is shown here. The read-write head (the silver arm you see suspended over the top of the rust-colored platter), rides on an ultra-thin layer of air as the platter (disk) spins.

This separation is critical, because if one of these heads comes in direct contact with highly-polished surface of the a platter, it will scratch it and possibly damage the head. In either case, major problems can result.

The read-write heads move very fast; they can flip back and forth over the total surface of the disk at least 50 times a second, while, at the same time, gathering or recording data. The hard drive shown above has four platters and requires several read-write heads for the top and bottom surfaces of each platter.

As the platter spins and the read-write heads swing back and forth and digital data is magnetically transferred to or read from invisible microscopic tracks on the disk's surface.

These magnetic traces are organized into tracks and sectors.

Note that in the drawing on the left a sector or block of data is one segment of a track. Each sector contains a fixed number of bytes of information — generally 256 or 512 bytes. (These tracks are actually microscopic, but we've enlarged them so they could be seen in the drawing.)

For any number of reasons, including an unexpected loss of power, you should regularly save the information you are working on to the nonvolatile memory of your computer's hard drive. (Of course, most of us learn this the hard way when we lose an hour's work!)

Hard drives also have speed considerations. The speed at which data can be written to and read from a hard drive represents a major limiting factor in computer speed.

If you see the specifications on two hard drives, for example — one of which reads and writes information at 12ms (millionths of a second) and the other one at 8ms — you know that the smaller number is better because it represents less time.

The platters or disks rotate at a constant speed, which, depending on the design, may range from 3,600 to 7,200 rpm (revolutions per minute).

Although hard drives can have life spans of many thousands of hours, all of them, given enough time, will fail (crash). Like earthquakes in California, it isn't a matter of if, it's a matter of when. This can be caused by a strong jolt that crashes a head into the surface of a platter, or just by a part eventually wearing out.

When a hard drive fails — and that's often without any notice that a problem is even looming — you lose all of the data on the hard drive, which generally represents all of your data and programs.

The good news is that since computers tend to be obsolete after a few years, hard drives generally outlast the practical life of computers. But, of course, you can't count on that. Therefore, you need to keep the CDs of all your original programs along with their original installation keys, so the programs can be reinstalled.

Even if your hard drive doesn't crash, you sometimes have to reinstall programs when information gets corrupted on your hard drive by a virus or by a scrambled write-to-disk operation.

Computer Viruses

And speaking of viruses, with destructive viruses appearing on a daily basis, it's essential that you have anti-virus and firewall programs installed in your computer — especially if you spend time on the Internet.

The graph on the right shows how much cyber attacks and viruses cost U.S. businesses .

Note that about 5% of businesses (in red) had to pay out a half-million dollars or more to fix resulting problems, and 32% (in yellow) paid up to $10,000.

In 2005 and 2006, the number of viruses rose sharply. Many, if not most, come from outside the United States.

Corporations such as Microsoft offer large rewards for turning in anyone who releases a virus on the Internet. A number of virus writers are now serving prison terms for cyber attacks.

E-mail is a favorite target of virus scoundrels. Savvy users never open an e-mail attachment unless they know and trust the sender. Files that have attachments with .doc and .exe suffixes can easily contain viruses.

A good virus program can usually catch and stop these viruses from infecting your computer — if you regularly update your virus definition files. The leading companies have programs that do this automatically. A virus can wipe out everything on a hard drive,  requiring days of work to restore everything.

It's also important to regularly update your computer's operating system (OS). These generally come in the form of "patches" that are available from the company's website.

Because of potential problems, you need to keep at least one good copy of all of your important data on a non-volatile medium such as a USB jump drive (shown on the left) or a recordable CD.

This is called backing up your data. There seems to be a "Murpy's Law" involved here: it's only the original data that you failed to back up that will unexpectedly disappear or get destroyed!

Many homes still use a standard telephone line and service to connect to the Internet.  This is the ultimate bottleneck in Internet speed.

A modem, an acronym that stands for modulation-demodulation, changes digital computer information into sounds that can be sent (modulated) and received (demodulated) via telephone lines. Most modems, such as the one shown on the left, plug into a slots inside desktop computers. Laptop computers typically have them built in.

Since telephone lines were never meant to transmit digital data, the process of changing digital data into sounds that can be sent back and forth over telephone lines leaves much to be desired. Nevertheless, we already have our homes wired for telephones and the cost of rewiring them all for digital data would be prohibitive.

Looking back into computer history for  a moment, the first modems were introduced in the 1950s. They operated at less than 100bps (bits of data per second). By today's standards this is dreadfully slow, but at that time it was fast enough for such things as text-based airline reservations and AP news wires. In those days the Internet didn't display complex pages with images, only lines of text on black-and-white computer screens.

Then something called GUI (graphical user interface, pronounced goo-ey) was devised. This made it possible to display interactive images on computer screens.

Through a system of X-Y screen coordinates coupled with a mouse or pointing device the computer could be made "aware" of where a mouse was pointing.

Clicking a mouse button on one of these points (coordinates) could initiate an action.

After these developments, not only did computers become much more user friendly, but the foundation for hyperlinks and browsers (such as the program you are using to view this page) was established. It was also at this point that the famous "www" or Worldwide Web became a major category for addresses on the Internet.

A GUI requires thousands of times more digital data than the simple lines of text that had previously been a part of the Internet. So further R&D (research and development) on modems took place, resulting in step-by-step speed increases to 600, 1,200, 2,400, 2,800 and 5,400 bps.

Since analog data sent in the form of audio over telephone lines degrades with distance, the actual speed of your modem depends on how close you are to the nearest telephone switching station. If you are less than a mile away, or the switching equipment is in your office building, things can go fairly well. If you are at home, miles away from a switching station, modem speeds will be significantly lower than 52Kbps.

By this time in computer history various compression techniques were being used to condense digital data, and thus effectively speed up data flow through a modem.

Almost half of Internet users now have high-speed Internet connections in their homes --either through cable, high-speed telephone lines, or a satellite service. This has meant that those who develop materials for the Internet now have many more options available to them -- including full motion video.

If you are reading this in a library or school computer lab, the chances are that the computer is wired to the Internet with a high-speed connection  — possibly a T1 line.

T1 lines are capable of transmitting digital data at more than 1.5 megabits (billions of bits) per second -- thousands of times faster than the standard analog-based dial-up modem. There are also T3 lines that can transmit data more than three times faster than T1 lines, but at this point they are not widely used in institutional settings.

By 2007, about 50% of homes had some sort of high-speed Internet connection -- either through telephone lines, cable, or satellite.

The major cell phone systems  provide high-speed internet for both "smart phones" and laptop computers. The card shown on the right slips into a slot on a laptop and can download files at a rate of up to 3.6 Mbps (megabytes per second). 

Error Control

When you click on a computer hyperlink you may be taken to a computer site thousands of miles away. This means that the signal may have to be routed through hundreds of relay points and telephone amplifiers.

Since we are dealing with a series of tones coming from and being sent to your computer, telephone line noise, static, or distortion can obliterate the message. If it weren't for error correction your computer screen could regularly fill up with meaningless "garbage characters."

To try to stop this from happening the data is sent and received in blocks of information. Before a block is sent it's mathematically analyzed and a checksum (a calculated value reflecting the nature of the original data) is figured and transmitted along with the data block.

If the checksum on the receiving end doesn't match the checksum of the original data block, an error in the transmission is signaled. Then before the next block of data is sent, the receiving modem requests that the data block be resent. Having to retransmit blocks of data obviously slows down transmissions.

Errors tend to be more prevalent at high modem speeds. If the modem detects too many errors during a certain period of time, it's programmed to automatically lower its speed to a point where accuracy increases.

Although you may have a 54K modem, when it initially connects with your ISP (Internet service provider, such as Earthlink, or AOL), it may determine that a lower speed -- 45K or 33K -- is necessary for reliable transmissions. Thus, your connection speed is often lower than the top speed of your modem.

You might assume that the blocks of data are all sent over the Internet using the shortest route between computers. That's not necessarily the case. In fact, depending in Internet conditions, the blocks of data might each take very different geographic routes getting to a common destination.

This is actually one of the strengths of the Internet. If problems develop at one or more relay points, traffic is automatically rerouted. As we will see in the next module, this feature was a cornerstone in the original Internet design.

Each block of data that is sent over the Internet carries an "address." (There will be more on this in Internet Module 4.) Once the individual data blocks arrive at their destination, they are combined in the intended sequence.

This process can be likened to using dozens of post cards to send a term paper from one person to another. Each post card can only contain one or two sentences. Let's assume you address each post card to the same person and then drop them all in a mailbox. They may go different routes; some might even go by trucks and some by aircraft. Once they arrive at the common destination, they have to be put in the proper sequence. This analogy shows you a bit of the complexity of how data is sent over the Internet.

The Worldwide Wait

The Worldwide Web, especially with standard dial-up modems, is sometimes referred to as the "worldwide wait," because the Internet sometimes slows down to a crawl, or even freezes, during high use periods.

If the Internet had been designed from the beginning to accommodate millions of simultaneous users, these problems might have been avoided.

However, the original design didn't envision a fraction of the traffic we now see. Ever since the Internet "took off," equipment and facilities have been trying to play "catch up" -- and never quite catching up.

Spam

In 2007, 183 billion spam (unsolicited junk advertising) messages a day were being transmitted over the Internet. At that point more than 70 percent of all e-mail consisted of spam. Most of it consisted of bogus or questionable offers -- sometimes from pornographic web sites. 

While popular e-mail programs attempt in various ways to screen out the majority of spam, it still clogs the Internet. One study concluded that people and businesses spend 23-million hours a week just deleting these unwelcome messages.

Billions of dollars are spent on storage space for all of these "messages" before they arrive at their destinations to simply be deleted.
 

Phishing / Identity Theft

Phishing (pronounced "fishing") is a type of spam that appears to come from legitimate sources such as your bank, PayPal (an Internet charge service), or your local utilities company. It is relatively easy to make e-mail appear to come from a legitimate source.

Messages may have the authentic look of the real website and often claim a need to update personal information such as social security or credit card numbers. Put simply, it's an effort to steal (and illegally use) your personal information.

This is generally an attempt at identify theft where someone with your personal information assumes your identify and can apply for credit cards, loans, Internet purchases, etc.

The thief  will almost always initiate a change of address so that bills will not come to your address to be questioned. In can be some time before the identity theft is discovered -- long enough for your credit rating to be severely damaged. (If you don't get your monthly statement from a merchant -- check!.) 

Numerous expensive items may be purchased before you find out that someone is using your identity. Often, credit card companies will catch suspicious charges and call you, and you can initiate the process of  having these charges deleted.

There are also agencies that (for a yearly fee) will monitor your accounts and notify you of a change of address, a sudden jump in credit card purchases, or other types of suspicious activity.

Trying to fix things often involves filing a police report and having to deal with various agencies in an effort to clear your name of overdue and unpaid bills. It can take months -- sometimes even years -- to clear up these problems.

Suffice to say, don't give out personal information on the web unless our are certain that you are dealing with a legitimate business.

Although some people say to never give out a social security or credit card number on the Internet (or even the phone), many legitimate companies require this information.

Before transmitting personal information on the Internet you should check for the little locked symbol at the bottom of our browser indicating that the website you are using is operating in the secure mode and formation is being encrypted.

In the case of phishing you may notice that when you click on the merchant's address in the bogus e-mail that the address at the top of the browser shows another address or is a strange distortion of the merchant's real address. If in doubt, call the merchant.

Finally, when purchasing things over the Internet use your own computer -- or a computer you are certain has the latest Internet firewall and virus protector installed -- and not a public computer. Unprotected computers can have a variety of virus and trogon horse programs that can capture data and transmit it to undisclosed  locations.

Among these programs are "key loggers" that capture every keystroke and transmit it to a pre-programmed location.

Although most "spammers" and :"philshers" reside in a foreign country -- principally Russia -- out of reach of U.S. laws, bear in mind that even the U.S. government has the authority to monitor the content of Internet traffic. 

Most young people average numerous hours a week on the Internet

 A 2001 survey found that teens divide their Internet time into roughly six categories, as shown here.

In the next section we'll look at some more of the key elements in the Internet.

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