Q. I have several unknown files on my Macintosh. I have no idea what created them in the first place or what they contain. When I try to run them, the Mac says the correct application cannot be found. I don't want to delete them until I know what they contain. How do I determine that?
A. Invisible things such as a file's "bundle bit" and "file creator" -- which are automatically generated and maintained by the Macintosh Finder operating system -- help to identify a file. Unfortunately, there also are many things that can cause a file to lose this vital information.
For example, an icon (picture) visually links a file to a specific application. When a bundle bit or file creator is lost, the Macintosh cannot display the icon correctly. Instead, it displays the file as a generic icon, which offers no visual cue as to what program the file belongs.
You may have given the file a name that will indicate where it came from. If not, you are going to need help.
Looking at the data stored in the file is a great way to figure out what the file is. But to look inside the file, you need the program that created it. And since you don't know what that program is, you're caught in a vicious circle. Fortunately, there's Can Opener 2.
Metaphorically speaking, Can Opener does just what its namesake does. If you have a can with no label on it, use a can opener to see what's inside. Can Opener doesn't need to know what created a file in order to open it. It just opens it, or more specifically, it displays the file's contents on your screen.
Pictures, text or whatever the file contains will be displayed. To preserve the metaphor, Can Opener displays a little animated picture of a can turning in a can opener as it attempts to display the file's contents. Once you see what the file contains, you'll probably know what created it.
Another nice feature is Can Opener's ability to cut and paste data into other programs. This comes in handy if the file has been damaged beyond repair. At least you can extract information from the damaged file and paste it into a new file.
Can Opener can also search for and locate specific text. This is useful when you want to search several documents for a particular word or phrase. You can also store collections of text and pictures in library files for future reference.
Can Opener 2, available for the Macintosh only, sells for $125 and can be purchased from Abbott Systems, (800) 552-9157 or (914) 747-3116.
Q. I just got a modem for my computer. I understand that there are thousands of free computer bulletin-board services around the country. How can I find some in my area, and how easy are they to use?
A. A computer bulletin board, or BBS, is the equivalent of the cork board you see in supermarkets and public areas. Most computer bulletin boards are run out of people's homes as a hobby. Most are free or charge a nominal membership fee.
When your computer calls up a BBS, you can view messages from and post them to anyone with access to the BBS.
One thing you'll usually find is a list of other BBS systems and their phone numbers. That means you need to find only one system in your area. Calling others on the list will reveal their lists of numbers, and you're on your way.
(Send questions to Craig Crossman, Business Monday, 1 Herald Plaza, Miami, Fla. 33132. Please include your phone number.)