Please note: this is a draft version of this document. If you see any glaring errors, feel free to post a comment.
Viruses and Spyware
This section is for Windows users.
Most modern viruses use e-mail to spread. Most depend on the user opening an attachment either because of its enticing name (“My wife nude.jpg”) or because it appears to be from a trusted source. I say “most,” but certainly not all. Apparently, the average Russian teen with too much time on his hands is a more capable programmer than the average Microsoft Windows engineer. There are many holes in Windows, and many people who have nothing better to do than find those holes.
Most modern viruses aren’t out to kill your machine. Instead, they want to take it over and use it as a zombie. For some viruses, this means reading your address book and sending messages to everyone in it. Sometimes they send messages that spread the virus. Other times, they send spam from your machine (your friend’s spam filter is less likely to object to a message coming from a trusted sender.) This kind of virus can slow your machine a little, as it’s constantly sending out messages.
Other common viruses use your machine to attack specific web sites on the internet. This kind of attack is called a “denial of service” or DOS attack. The virus writer uses the thousands of machines he’s infected to bring a web site to its knees simply by having all of the zombies send requests for data at the same time. In most cases, this is simply the computer equivalent of vandalism. However, some of these DOS viruses have been used to extort money from large corporations.
Spyware could be considered another sub-category of virus, as it gets installed on your machine unbidden. Spyware is more dangerous to you as a user than the above virus types. Spyware attempts to glean personal information about you. Sometimes it’s as simple as finding out which web sites you visit. Sometimes it’s as insidious as copying your credit card numbers.
Microsoft has finally released its own anti-spyware/anti-virus program. It’s called Windows Live Safety Center. As I write this, they’re still calling it beta software, but it seems to be in reasonably good shape, and… it’s free. SC scans your computer for viruses and spyware, and can also run a “tune up” on your computer. It might be a good idea to run SC on your computer once a month. It’s located at http://safety.live.com. Note that it may take hours to complete a scan.
Safety Center not withstanding, one thing you can do to give your computer a little more speed is to de-fragment your hard disk. You may remember from the “How Your Computer Works” article that hard drives have tiny floating heads that scan across the surface of a rapidly spinning disk. As your hard disk starts to fill up with mp3’s, Word docs, and porn, some files become fragmented. That is, they’re not written on the disk in one continuous strip. Part of a file might be near one end of the disk, part might be near the other. So when the hard disk wants to read the file, it has to jump its floating heads from one place to another. Imagine having a record where the song you want to play is in sections. You have to keep lifting up the needle and moving it to a different place to hear the next part of the song. Obviously, this takes more time, and there’s more wear-and-tear on both you and the record player. It’s the same with fragmented files on your hard disk.
To run Disk Defragmenter, open the Start menu, then All Programs, then the Accessories folder, then the System Tools folder, then Disk Defragmenter. Note that this is another tool that can take hours to run. However, you can use your computer (it will be slow) while DD is running.
Why Your Internet Connection is Suddenly So Slow
Mac users may begin reading again.
Chances are, you’re reading this on my blog. If so, this is what happened: You told your computer that you wanted to load this web page by clicking on a link. Your computer sent a packet asking for the page to your dsl or cable modem. The modem sent the packet to a router in your local telephone office or cable company office. That router looked at the “to:” address on the packet. The router is connected to several other routers. It decided, based on the address, which router to forward the packet to next. This process was repeated anywhere from 12 to 20 times, router to router, until the packet asking for this web page arrived in an air-conditioned room in Boston, where the actual kenlaws.tv server lives. The server received the packet and began to send a series of packets back (this is a big file) to your machine. Each packet traveled back across the country, quite possibly taking a different path, until it arrived at your computer. As each packet was received, your computer sent out yet another packet telling the server in Boston that, yes, the packet it sent came through. There are some graphic elements on this web page. Your web browser read the HTML file sent from Boston, found any graphic elements within, and sent requests – just like that first request – for each of the pictures. So for each picture – the background, the gradient near the top of the page, etc. – a request packet went across the country, packets were sent back, acknowledgment packets went back the other way, each and every one passing through at least a dozen routers along the way.
This happens every time you go to any web page.
But wait, there’s more: Remember, the first request was just for the HTML file – the file that tells the browser the basic structure and content of the page. Browsers often can’t display a page until at least some of the graphics have been downloaded. That’s because the size of some pictures affects how the rest of the contents will “flow,” for example, how some text might wrap around the picture. And then, on commercial web sites, there’s one more thing to consider. The HTML file tells the browser what it needs to download to display the page. That can include ads. Ads on a web page are typically downloaded from the ad company’s server, not from, for example, MySpace. When you open your home page on MySpace, the pictures and text come from MySpace, but the ads are being loaded from another company’s server. That ad server might be slow, or down, or have some other problem. Since browsers sometimes have to wait for a picture to know how to “flow” the rest of the page, you could find yourself sitting and waiting for a page to load because the ad, the most useless part of the page, hasn’t been loaded yet.
Sometimes, if you’re visiting a site you’ve been to before, your web browser will load a particular picture from your computer’s local cache, which is kept on your hard drive. However, even if you have a picture on your machine, most web browsers will still send a packet to the server to make sure that the file you have is the current version.
So why does a web site suddenly seem slow, or stop loading altogether? At any time, day or night, there are tens of millions of people on the web. There are also millions of e-mails flying back and forth, many of them spam, from one address to another. There are routers spread out across the country and around the world. Most of them are very fast. However, it’s possible for one to become “clogged” for a moment or for a few hours due to a sudden increase in traffic, a DOS attack, or human error in setting it up (more common than you’d think.) Of course, there are hundreds of paths from one computer to another. But sometimes a router thinks a path is “clear,” and tries to use it, only to find out the next router in line is clogged up.
Large web sites are also susceptible to succumbing to their own success. MySpace is an excellent example of this. Thousands of people join every day. MySpace has to keep up by adding and configuring new servers constantly. But servers, and the people to set them up, cost money. And the setup takes time. So one day bulletins might seem slow. Another day it’s mail, or pictures. It never ends.
There are dozens of failure points, dozens of places where a lonely packet from your computer can get lost. But sometimes, a slow or non-responsive net connection might have something to do with your DSL or cable modem. Remember, these modems are on 24/7, and after a couple of months, they can collect a little bit of electronic garbage.
In order to properly reset your modem, unplug it (or use the on/off switch) for a full 90 seconds. Turn off your computer at the same time. If you have a router (wireless or otherwise,) turn it off, too. After the 90 seconds, plug in your modem. Wait for the “connect” light to come on (steady, not blinking.) Then turn on your router and give it a few moments to warm up. Finally, turn on your computer again. This actually works unexpectedly often.
As a rule, DSL or cable company phone support personnel will have very little interest in helping you resolve speed issues with specific sites. For piece of mind, and to find out just how fast your connection is, try going to http://www.dslreports.com/stest. This will perform a speed test on your line. It’s a good idea to try it when you think your connection is “fast,” so you’ll have a base number to go on. Then, when you think your connection is “slow,” you can run the test again and see if anything’s really changed with your line. If not, you can guess that the slowness is caused more by internet traffic congestion or a slow web server than with any problem on your computer.
Macs and Viruses
Is it true that there are no viruses on the Mac? Sort of. A couple of people have written “proof of concept” viruses. Apple updated OS X to close the holes those semi-viruses used. The Mac is protected from viruses for three reasons:
- Macs make up a much smaller part of the computer market than Windows machines. As you read above, most viruses want to spread spam or run DOS attacks. These goals require lots of infected computers. If there are more Windows users than Mac users, it behooves the virus writer to write for Windows.
- The Mac OS is based on Unix, which has a much more robust, time-tested security system than Windows. Unix has been around since the late ‘60’s. Windows got started about 20 years later.
- On the Mac, you have to enter your password anytime you want to install a new piece of software. This makes you a little more aware that something important is about to happen.
Macs have been slowly gaining market share for the past couple of years. Should that continue, will there be a sudden surge in Mac viruses? I think the second two reasons above would indicate “no.” I make a lot of computer “house calls” for my friends. I once found and removed 168 viruses from a Windows machine. Even if some vulnerabilities are found in OS X, I don’t think I’ll ever remove 168 viruses from a Mac.