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.

At the same time, CPU speed is only one of the elements on the motherboard (the main circuit board area of the computer) that determines computer speed.  Part of a motherboard 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

As we've noted, CPU speed is only one of several factors that determine how fast things will happen in your computer. Equally as important is the amount of memory your computer has.

Computers today must have at least one gigabyte of RAM (random-access memory). Most PC and Apple machines now come equipped with at least two gigabytes of RAM -- the minimum needed to effectively run today's operating systems.

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.

Not only the amount, but the speed of the 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.

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 -- up to the maximum allowed by your computer.

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 this 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. (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 in nonvolatile memory -- generally 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 10,000 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 today's 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 they can be reinstalled.

Studies have shown that if a new hard drive doesn't develop any problems in the first couple months --which most don't -- there is a very high probably that it will last several years.

Even if your hard drive doesn't crash, you will occasionally 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 / Malware

Speaking of viruses, with destructive viruses appearing on a daily basis, it's essential that you have anti-virus, anti-spyware, and firewall programs installed in your computer — especially if you spend time on the Internet. A virus can wipe out everything on a hard drive, requiring days of work to restore everything.

The graph on the right shows how much cyber attacks (often called malware) of various sorts cost U.S. businesses .

Malware includes computer viruses, worms, trojan horses, most rootkits, spyware, dishonest adware, and other malicious and unwanted software.  Most people just refer to most all of them as "computer viruses."

One of the most insidious and dangerous types is the keylogger, which can secretly record every keystroke you enter in your computer -- and send it to a remote point.

These programs can be planted in your computer through a downloaded program or an e-mail attachment. 

Many businesses use these programs on company computers to see what their employees are doing on the Internet.  Employee transgressions can range from wasting time to revealing trade secrets.

Although companies may have a legal right to do this, when it comes to your home computer you don't want a program like this eavesdropping on you -- especially when you type in banking and credit card passwords. Fortunately, many programs designed to detect and eliminate malware can catch eliminate keyloggers -- even before they infect your computer.

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 writing 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 malware.

Also avoid clicking on links in e-mails.  They can easily surruptiously plant malware in your computer. Your friends may even forward e-mail attachments to you, not realizing that they contain malware. This is sometimes the case when people forward popular videos or programs they discover.

Good anti-virus, and anti-spyware programs can usually catch and stop malware from infecting your computer  — but you have to regularly update them.

Software updates are sent out on a regular -- generally on a daily -- basis. There are also regular updates for the Windows and Mac operating systems (OSs).

These updates are important, and there is one reason that most people don't know about.

The OS updates generally focus on newly discovered security vulnerabilities in the operating system that can allow malware in to attack the system.

One of the negative side effects of this is that in the process it reveals these OS vulnerabilities to the "bad guys."  The malware code writers can then immediately take advantage of the vulnerabilities that have been revealed in the updates.

The "bad guys" assume -- correctly, unfortunately -- that many people will not immediately upgrade their software. So unless you upgrade your operating system or virus or spyware software as soon as possible, these newly revealed vulnerabilities can be used in quick attacks.

If you computer stays on line, these updates may (and should be) automatic. If so, there will probably not be a problem. However, as you can see, if you don't update your software as soon as you go on line, or allow your computer to immediately do updates, you can get "hit" by malware.

As we've noted, you need to keep at least one copy of all of your important data on a non-volatile medium such as a USB jump drive (shown on the left), a recordable CD or a external hard drive

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!  Companies often routinely back up critical data at the end of each work day.

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.

Many modems, such as the one shown on the left, plug into a slots inside desktop computers. Laptop computers typically have them built in (and they are much smaller)..

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 in black-and-white.

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.

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.

Although those speed increases might seem impressive, they are too slow for today's Internet needs. For ont thing they typically rely on the original telephone lines that are inefficient in transmitting digital computer data.

Today, most homes have some form of high-speed internet that typically uses coaxial cable -- the kind that cable TV uses -- or special high-speed telephone lines.

Although a single computer can be directly connected (hardwired) to the Internet connection, in homes with multiple computers the signal can first be directed to a wireless router, such as the one shown below.  From there the signal can be picked up by any WiFi equipped computer within at least 30 meters (100 feet).

In order to communicate with the router, each computer must also send out a signal.

Since anyone within the effective range can pick up both of these signals, it means that someone sitting outside of your home (or in a nearby house or apartment) could conceivably eavesdrop on anything being sent from any of your computers.

For this reason routers have a way of "securing the network" by programming a password into the router.  This password must also be used in the computers to access the router's Internet signal. 

Although so-called unsecured networks are available in places like cybercafes that offer free WiFi internet service -- meaning that anyone can use them -- this is not a "feature" you want in your home or business systems. 

Today, many hotels, motels, and airports provide WiFi service -- generally for a daily or weekly fee.

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.

The major cell phone companies 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 Mb (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.

If it weren't for error correction, momentary interference or interruptions could easy scramble the message. To stop this from happening 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 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 signal is transmitted to the originating source. Then that data block is immediately sent again.

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.

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 within a single message can take very different geographic routes getting to their 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 with each post card containing 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. From there they could 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 2008, about 200-billion spam messages (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. 

While popular e-mail programs attempt 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 also spent on storage space for all of these "messages" before they arrive at their destinations to simply be deleted. Although laws in the United States discourage spammers, most spam comes from outside the United States, beyond the control of U.S. law.
 

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. These messages typically 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 that gets 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 -- in some cases 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 (often a padlock icon) indicating that the website you are using is operating in the secure mode and information 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 or misspelling 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  keylogger programs that can capture data and transmit it to undisclosed  locations.

Most young people average numerous hours a week on the Internet

 A recent 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.

• More information on some of these topics can be found in the Resources file.