Friday the 13th might bring bad luck to some microcomputer users. Officials at the Hebrew University of Jerusalem recently discovered a new
``computer virus`` that was set to activate itself tonight and to wipe out all the data on any disk it has infected.
Saturday is the 40th anniversary of the foundation of Israel, and speculation is that someone created the virus to disrupt normal activity in the Jewish state. The way computer viruses work, though, it could disrupt things here as well. Though university officials were able to quarantine most disks that hold the virus, there remains the chance that some infected copies are still around.
A computer virus is a small computer program that attaches itself parasitically to another program. Usually the virus program attempts to stay hidden; that is, if you display a directory of a disk, you will not see any file named ``VIRUS.COM.`` A computer virus also tries to replicate itself and attach itself to other programs and disks. At a certain predetermined time, the virus springs into action, either destroying data on the infected disks or playing some high-tech pranks.
When the first spate of virus stories came out this year, I dismissed most of them as hysterical overreactions to isolated incidents. Now I`m not so sure. Too many viruses have struck at too many unexpected places for a computer user not to be concerned. For example, Macintosh computers at NASA and at the Apple sales office in Washington, D.C., were infected recently by a sophisticated virus that caused systems to crash, printers to malfunction and files to be destroyed. By now the virus has spread throughout the country. And a virus at Lehigh University destroyed 610 diskettes in midterms week.
Moreover, the highly respected Aldus Corp. recently announced that many copies of FreeHand, a drawing program for the Macintosh, have become infected. When the program starts up, infected copies display on the screen the greeting, ``Peace to all Macintosh Users.`` Upon investigation, the disseminator of the virus was found to be Richard Brandow, publisher of a Montreal-based computer journal called MacMag, who said publicly he was simply trying to make a political statement.
Now that sounds rather harmless, and indeed such viruses have been labeled ``benign viruses`` to distinguish them from the malignant viruses that destroy data or hang up your system. However, in a sense no virus is harmless. Any virus takes up extra space on disk and in memory-space that belongs to you. Like any invasion, a computer virus should be fought.
In dealing with a biological virus, the big question is, ``Will I get it?`` With a computer virus, you wonder, ``Is there any chance that this virus or one like it could damage my system?`` Unfortunately, the answer is yes. Even if a virus starts halfway across the world, like the Hebrew University virus, it could be unwittingly transferred by modem to anywhere else on the planet in a matter of moments.
However, some groups of users are in more of a high-risk group than others. If you are a user of an electronic bulletin board system; if you transfer data by modem; if you use a computer networked to other computers;
or if you exchange diskettes with other computer users, then you run the risk of picking up a computer virus. If instead your computer is never hooked up to any other computer, and if the disks you use are all store- bought commercial software, then your chances of coming down with a computer virus are practically nil.
If you are in a high-risk group, you can take steps to protect your system. For one thing, be very careful about what electronic bulletin boards you use. Major services such as CompuServe and The Source periodically check out every program on their system for infections, so you can feel fairly safe there. But many local bulletin boards are not so vigilant.
To spot a potential virus before it strikes, see if one of your program files has been altered in any way. If the file date or size of a program has changed, maybe a virus has attached itself. In addition, write-protect your original program disks, and be suspicious if a program attempts to write to that disk. And, of course, keep backups of all important files.
Finally, your most effective ounce of prevention is to invest in a software program that detects and contains infections. For example, the appropriately named program Vaccine offers six modules that help to protect disks and main memory from not only viruses but also from accidental mistakes that users sometimes make, such as inadvertently formatting a hard drive. Vaccine can be ordered by calling FoundationWare at 800-722-8737. It costs $92 until May 31 and $189 later, and is available for the IBM-PC and compatibles only.
Apple owners should stop by their local Apple dealer to pick up Virus RX, a free program developed by a ``virus task force`` at Apple headquarters. The program is also available through Applelink and other electronic bulletin boards.
Have a question about home computing? Address it to Dennis Lynch in care of Friday Audio-Video Section, The Chicago Tribune, 435 N. Michigan Ave., Chicago, Ill. 60611. Questions of broadest general interest will be considered for future columns.