Apple Macintosh PowerBook 150 - Manual (Page 141)

Before you can assign a Macintosh program to a group of DOS documents,
you need to answer three questions:
m What suffix do the documents have in common?
Many DOS programs automatically add a three-letter suffix (or filename
extension) to a document’s name. For example, these PageMaker documents
all share the suffix .PM4:
NEWS.PM4
REPORT.PM4
RESUME.PM4
m
What Macintosh application program do you want to use to open the documents?
Each Macintosh document has a creator—that is, the Macintosh program
used to create the document. When you double-click a document’s icon,
the Macintosh opens the program that created the document.
Using the PC Exchange control panel, you can assign Macintosh programs
to DOS documents as “creators.”
m What type of document is it?
Most programs are able to open or import some, but not all, types of
documents. A document’s type is a three- or four-letter code (such as TEXT
or PICT) that tells a program whether or not it can recognize the
document. A program displays documents of types it can recognize in its
directory dialog box.
Unless you specify otherwise, the Macintosh assumes that all DOS
documents have the document type TEXT. You can assign different types
to some DOS documents. See the next section.
A document’s type is different from its file format, which refers to the way
information within the document is encoded. If a program is unable to
accurately interpret a document’s file format, the document’s formatting may
be displayed incorrectly. (To find out which file formats a program can
understand, refer to the documentation for the program.)
133 Exchanging Files with DOS or Windows