CyberCollege / InternetCampus

  Updated: 05/01/2013

The Internet - 2

 

 

 

Computers and

the Internet

 

 

 

Another famous utterance that was soon regretted:

"Computers in the future may weigh no more than 1.5 tons."

-Popular Mechanics magazine in 1949, forecasting the future of computers.

 

>>The illustration below shows the basic components of a computer. They hold true for all types of computers, including desktops, laptops and tablets. (Although in the latter case the hard disk is generally replaced by solid-state memory.)

 

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 seem to become obsolete.

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

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 two gigabytes of RAM (random-access memory) to run sophisticated programs. Most Windows and Apple machines now come equipped with two-to-four gigabytes of RAM..

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 your hard 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 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 saved to and then read from the hard drive.  That 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

Before we get to this we need to point out the difference between "disks" and "discs." 

Although the spelling is often confused, disc refers to optical media, such as an audio CD, CD-ROM, DVD-ROM, DVD-RAM, or DVD-Video disc. All discs are removable, meaning when you unmount or eject the disc it comes out of the player.

The term disks refers to magnetic media, such as a floppy disk, the disk in your computer's hard drive, or an external hard drive. Disks are always rewritable unless intentionally locked or write-protected.


>>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  platter (instead of floating a hair's width above it), 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. 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 can lose all of the data on the hard drive. For this reason you should regularly back up all your important files.

Solid-State Computer Drives

Solid State Drive>>Mechanical hard drives have a number of disadvantages and so in 2010 solid-state drives appeared on the scene.

Solid-state drives provide faster access to data, consume less power (important for laptop computers), have a longer lifespan, are shock proof, and are silent.

Their main disadvantage at this point is that they don't have as high as capacity as hard disks.

Backing Up Data

>>You need to back up important data on a non-volatile medium such as a USB jump or thumb drive (shown on the  left), a recordable CD, or a external hard drive

There seems to be a "Murpy's Law" involved here: it's only the data that you failed to back up that will unexpectedly disappear, become corrupted, or get destroyed! 

You also need to keep the CDs of all your original programs along with their original installation keys, so they can be reinstalled. 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.

Companies commonly back up critical data on a daily basis. There are services that will do this automatically via the Internet.

Recently, cloud drives have become popular.  These are Internet storage areas that appear as an extra drive on your computer that you can upload and download files to. Some are free for limited storage; after which you pay for additional storage space.

 

Computer Viruses / Malware

>>New 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.cost of virus attacks

The graph on the right shows how much cyber attacks (often called malware) of various sorts cost U.S. businesses. (Since that chart was created things have gotten much worse.)

Malware includes computer viruses, worms, trojan horses, most rootkits, spyware, and other malicious and unwanted software.  Most people just lump these all together as "computer viruses."

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

These programs can be planted in your computer through a questionable program downloaded from the Internet or an e-mail attachment which you've opened, thinking it was from a trusted friend.

But that "trusted friend" could be someone who hacked into your computer even from another country and copied all your email addresses to send out email in your name.*

" Keyloggers can read every email you send or receive, see every instant message or chat you take part in, see every web page you visit, take screen shots of your computer screen including graphics and videos you see, and even notify the interloper when 'alert words' are used in any of your communications." 

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Many businesses use such 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. Many of the basic versions of these programs are free to download from the Internet.

computer keyboard>>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 contain malware.
Your friends may even forward e-mail attachments to you, not realizing that they contain malware. A department head at a university sent everyone in the department "a cute little animation" recently -- infecting not only all the people he sent the file to, but everyone these people forwarded it to. The good news is that those who write anti-virus programs are generally able to stay on top of these threats. There are also regular updates (patches) for the Windows and Mac operating systems (OSs).laptop computer
 Corporations such as Microsoft offer large rewards for turning in anyone who releases malware on the Internet. A number of virus writers are now serving prison terms for cyber attacks.The OS updates generally focus on newly discovered security vulnerabilities in the operating system. The downside of this is that the malware code writers can then immediately take advantage of the vulnerabilities that have been revealed. 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.

Windows malware programs can be set to automatically and regularly update virus protection. Although Mac/Apple computers are not as vulnerable  as Windows machines, malware protection is still  recommended.

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 utility company. It is relatively easy to make any e-mail appear to come from a legitimate source.

Messages may have the authentic look of the real website. They 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 often an attempt at identify theft where someone that gets your personal information assumes (takes over) your identify and can apply for new credit cards, loans, Internet purchases, etc. This doesn't have to come from the Internet. These people often get their information from papers that have been discarded  that contain personal information such as social security numbers.

The thief  will generally 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!) 

Often, credit card companies will catch suspicious charges and call you, and you can initiate the process of having these charges deleted -- if you can prove that you didn't make them.

Although it might not be too difficult to prove you couldn't have made charges at a store in another state at a specific time, it's much harder to prove you didn't make purchases over the Internet.

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

Trying to fix things after the fact 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 years -- to clear up all of these problems.

Suffice to say -- and this bears repeating -- don't give out personal information on the web unless our are certain that you are dealing with a legitimate business and you have secure connection to the Internet. Before transmitting personal information on the Internet you should check for the little secure 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. 

You can also check for an "s" (for secure) in the Internet address once you sign in and before you provide your user name or password, as in https://www.mybank.com.

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. This may also alert the merchant to warn users of the scam.

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

 

Spam

>>In 2008, about 200-billion spam messages (unsolicited junk advertising messages) a day were being transmitted over the Internet. Most of it consisted of questionable offers. 

In Microsoft's latest biannual report on the state of computer security, the company says that a full 97.3 percent of e-mail traffic is unwanted spam.

Pharmacy and other product ads make up the lion's share of spam, accounting for 72.2 percent of all spam sent. Ten percent of total share involves sexually-oriented material, which is a major decline from previous studies.

While some e-mail programs can screen out the majority of spam, it still clogs the Internet. One study concluded that people and businesses spend 23-million hours a week deleting spam.

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.

 >>Most young people average many hours a week on the Internet

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


* This happened to the writer a few days ago, possibly because I hadn't changed his email password for some time. But to guard against this kind of thing I had inserted several bogus addresses into the email address book, which meant that I immediately got some "no such address --return to sender " replies. 

So within minutes I was  tipped off to what had happened.  I quickly notified people in my address book not to click on the link in the bogus mail.  Then I changed my password and added more security to the email program.

I should also add this, since it's also related to this discussion. In checking to see if the feature of typing in "Google" with control-return as explained above worked, I somehow ended up on a bogus site. Fortunately my Norton 360 malware virus program caught what I was supposed to receive -- a severe virus, it reported -- and blocked it before it could do any damage. The program probably paid for itself right then!

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