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Computing With Bifocals
by Nancy Carroll Gravley

A column for people who remember what
the world was like before there was color.....

Computer Viruses and What To Do With Them
May 26th, 1999

The topic for this week is computer viruses - what they are, what they are not, and what can you do about them. I will also tell you how to use one of the most popular anti-virus software products specifically designed for Macs. I also have a handy guide that tells you what kind of processor you have in your Mac. Why? It will make sense, I promise.

What's a virus anyway?

A computer virus is a small computer program that can makes its way to your hard drive. Once there it may make copies of itself, erase a disk, corrupt your programs or create general havoc on your machine. The virus may also directly or indirectly copy, to and spread from, program files or sectors of your disk or files that use Microsoft Word Macros. They circulate from one computer to another via diskettes or across the Internet (via files that you may download from web sites or FTP sites). Diskettes borrowed from friends, school, or work are common sources, and even brand new diskettes can be infected. This happened to us at work and a great number of machines were affected before we identified the source. Of course, these were Windows computers which are far more susceptible to viruses. The name virus, as applied to this topic, was first used in 1984 by Professor Fred Cohen to describe these self-replicating programs.

The name is appropriate because like a biological virus, a computer virus is small, can make copies of itself, and cannot exist without a host. It's also a catchier name than Parasitic Self-Replicating Program. source: Henri Delger of VirusTech. These viruses are always man made by people who know how to write computer programs. I guess there are always a few people out there who feel important if they can cause problems for others; and the anonymity of the Internet allows them to do it. Some are created as pranks and some are created intending viscous harm. They can even be altered by others as they are passed around, so what may start out as a prank can end up as an extremely harmful virus. Mac viruses don't work on DOS based machines and vice versa (though those Word Macro viruses we mentioned can spread across platforms). Historically, there were only a couple of viruses a year identified for Macs. Unfortunately that number is now increasing, with some estimates as much as a 33% increase, which still leaves us in much better shape than those poor souls laboring away on Windows computers.

What about e-mail viruses?

On the positive side, there is no such thing as E-mail viruses. These are purported to be viruses that are sent through E-mail messages. The usual story is that if you open an E-mail message containing a virus it will immediately attack your machine. The stories usually include how to identify the offending E-mail message and what damage it is supposed to cause. People hear this and send out messages to everyone they know to warn them and the myth spreads. If you receive such messages you can safely ignore them. In fact, you should ignore them or you become part of the problem of spreading this misinformation. The reason why is that a program has to be launched in order for the virus to be activated. Opening an e-mail is not the same thing as launching a program. You can have a virus sent to you through e-mail, it would be in an infected file. So the rule of thumb here is that you don't open files sent as an attachment from people you don't know, but don't worry about the actual e-mail itself.

There is a lot of information on the net about viruses and I found, sponsored by Symantec Corporation, to be a good source if you want to learn more.

What do I do about them?

Understanding viruses is all well and good, but what is really important is knowing how to prevent or destroy them, even when you don't know they are there. This takes software. I am reviewing Norton AntiVirus for Macintosh 5.0. This software requires a Mac 68040 processor or higher or a Power Macintosh (including iMacs and G3s) with System 7.5 or greater. (See end of column for additional information on the processor available on your machine. ) It sells for about $70 unless you have a registered copy of Norton Utilities for the Macintosh. In that case the purchase price is $30. You can also try it out for 30 days by downloading it at Updates are free for registered copies the first year after purchase. Updates are important because as new viruses are created, new techniques are necessary to destroy them.

This software is very easy to use and anyone who can operate their computer at the basic level can use it. I had to try it out on a friend's computer because mine is a Mac 68030. I have System 7.6.1, but it is not a Power Macintosh. You probably want to make sure your machine will handle the program before you spend the money. To find out what you have you can check out the table and ther information at the end of this column.

To use Norton Anti-Virus for the Mac, version 5.0

It installs from a CD, so you willneed a CD-ROM to install it. Once the CD is inserted in your machine, a Norton AntiVirus icon will appear on your desk top. Click on that and a folder will open. Inside that folder are several other folders, one of which is diamond shaped and labeled AntiVirus Installer. (I told you it was very easy to use.) Click on the installer icon and follow directions. After you promise to give up your first born if you violate the user agreement, you are taken to a screen that allows you to scan for viruses. At the top is a box labeled scans with AutoRepair and to the right are three buttons for pause, continue, and cancel. You can also choose to set your own preferences, but it works just fine if you just leave the defaults turned on. (You do this by leaving everything alone.) My friend's computer is loaded down with programs, data, and information. It took about 12 minutes for the AntiVirus program to check everything on his hard drive. It found one virus which it automatically deleted as it went and cleaned any files affected. Those files were listed when the scan was finished. That's about it. Anytime you want to scan your computer again, just run the program again. You can set the preferences to automatically scan incoming disks. If you download a lot of files from the Internet or if you have a lot of floppy disks being used on your computer, run the program as often as once a week, or whenever you think your Mac may be infected.

About those processors.

I had never known all this information about processors or that they were different for different machines. It was not until I tried to load the software on my 68030 that I discovered that this is important information. My technical friends tried to explain it to me, but I think the really important thing for novice users is to just know what yours is so you don't buy software that you can't use. John Braun of The Mac Observer staff told me about a nifty, free program called Guru 2.7.1, that gives information about every Mac and clone ever made, including processor size. It too is easy to use, but you have to know the model name of the Mac you want information on in order to find what you need. You can download the program at

I know some of you may not want to hassle with downloading the software, so I also put together a table with all (I am counting on any Observer who may catch a Mac that is missing to let me know so I can fill in any holes) the Mac models and the kind of processor in them. There are 3 basic groups – those 68030 or under, those with a 68040 in them, and power PC's. Many of the newer programs will not work on anything less than 68040. If your machine is not here, or if you would like all the information about your particular machine that can be found in the Guru data set, just e-mail me and request it and I will e-mail it back to you.

[Editor's Note: We received many letters letting us know of some mistakes in the table as we originally posted it. We have replaced the original table with this corrected one. If you find any mistakes in this version, please let us know ASAP! Thanks to those Observer who wrote in.]

The List
Line Model Processor
Performa 200 through 467series 68030
Performa 520 through 560 series 68030
Performa 475, 476 68040
Performa 575 through 588CD 68040
Performa 600 68030
Performa 630, 630CD, 631CD, 635CD, 636CD, 637CD, 638CD, 640 68040
Macintosh 128K 68000
Macintosh 512K 68000
Macintosh 512Ke 68000
Macintosh Classic 68000
Macintosh Classic II 68030
Macintosh Color Classic 68030
Macintosh Color Classic II 68030
Macintosh II 68020
Macintosh IIci, IIcx, IIfx, IIsi, IIvi, IIvx, IIx 68030
Macintosh LC 68020
Macintosh LC475 68040
Macintosh LC520 68030
Macintosh LC550 68030
Macintosh LC575 68040
Macintosh LC580 68040
Macintosh LC630, 630 DOS Compatible 68040
Macintosh LC II, LC III, LC III+, 68030
Macintosh Plus 68000
Macintosh SE 68000
Macintosh SE/30 68030
PowerBook 100 68000
PowerBook 140, 145B, 150, 160, 165C, 170, 180, 180C 68030
PowerBook 190/66, 190cs/66 68040
Centris all models 68040
Quadra all models 68040
PowerMac 4400/160, 4400/200, 4400/200 PC Compatible PowerPC 603e
PowerMac 5200/75 LC PowerPC 603
Performa 5260/100, 5260/120, 5300/100 LC PowerPC 603e
PowerMac 5400/120, 5400/180, 5400/200 PowerPC 603e
Perfoirma 5500/225, 5500/250, 5500/275 PowerPC 603e
PowerMac 6100/60, 6100/60 AV, 6100/66, 6100/66 AV, 6100/66 DOS Compatible PowerPC 601
PowerMac 6200/75 PowerPC 603
PowerMac 6300/120, 6360/160 PowerPC 603e
PowerMac 6400/200 PowerPC 603e
PowerMac 6500/225, 6500/250, 6500/275 PowerPC 603e
PowerMac 7100/66, 7100/66 AV, 7100/80, 7100/80 AV PowerPC 601
PowerMac 7200/90, 7200/120, 7200/120 PC Compatible, 7215/90 PowerPC 601
PowerMac 7220/200, 7220/200 PC Compatible PowerPC 603e
PowerMac 7300/166, 7300/180 PC Compatible, 7300/200 PowerPC 604e
PowerMac 7500/100 PowerPC 601
PowerMac 7600/120, 7600/132 PowerPC 604
PowerMac 7600/200 PowerPC 604e
PowerMac 8100/80, 8100/80 AV, 8100/100, 8100/100 AV, 8100/110, 8115/110 PowerPC 601
PowerMac 8200/100, 8200/120 PowerPC 601
PowerMac 8500/120, 8500/132, 8500/150, 8515/120 PowerPC 604
PowerMac 9500/120, 9500/132, 9500/150, 9515/132 PowerPC 604
PowerMac 9500/180MP, 9500/200 PowerPC 604e
PowerMac 9600/200, 9600/200MP, 9600/233 PowerPC 604e
PowerMac 9600/300, 9600/350 PowerPC 604e
(Mach V)
PowerMac Twentieth Century Macintosh PowerPC 603e
iMac All models PowerPC (G3)
PowerMac G3 (Beige) Power PC (G3)
PowerMac Blue & White G3 Power PC (G3)

If you have any tips, hints, or thoughts on these topics, make sure you write me so that I can share your thoughts with other readers.

Copies of Nancy's book Tips, Hints, and Solutions for Seasoned Beginners Using Apple Macintosh Computers With OS X are available in PDF download versions  for US$9.57 and in print version for $18.15 plus $4.00 shipping.   To view sample pages and get ordering information visit the September 14, 2004 column.

Post your comments below.
Check out Nancy's complete index of all her columns for the most complete list of tips anywhere. The list is categorized and is a great reference when you are looking for help!

A Capacious Catalog Of Computer Tips

Talking to a generation that remembers what the world was like before there was color, covers issues for people who don't care how their computer works, but rather what their computer and the internet can do for them.

Nancy has a Master's degree in Human Services Administration and prior to her retirement she worked for almost 30 years in field of mental health and mental retardation. She has been a Mac user for 11 years, and has recently developed an avocation of teaching basic computer skills in both group and one-to-one settings.

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