What makes Mac different

Apple's Macintosh is light (about 20 pounds) and small, filling about the same area on a desk as a large dictionary. Sophisticated graphics and a tethered ''mouse'' are the major differences between the Mac and its competitors. Sliding the mouse (a palm-size pointing device) on the table moves the cursor quickly around the computer's screen.

Like the Lisa, the Mac's black-and-white screen contains small pictures, called icons, which represent various operations: a tiny trash can means deletion, for instance, and a little file folder represents filing. By placing the cursor on an icon and clicking the button on the back of the mouse, the operation it represents is carried out.

The Mac's text can be displayed (and printed) in a number of sizes and fonts. People with an artistic bent can sketch pictures or diagrams on the screen. Text and illustrations can be freely mixed. There is a sophisticated, four-voice sound capability which programs can utilize. With a utility called cut-and-paste , Mac's operator can transfer information between various applications even though the computer will only run one major application at a time.

Still, all this ''user friendliness'' is not bought without some cost. For example, if cutting and pasting a picture into a letter, it takes time to switch programs. First, one must ''cut'' it from the screen and exit the drawing program. Then one must load the word processing program and paste the drawing into it. This transfer can take 20 to 30 seconds - a delay that could annoy someone who switches frequently between applications.