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Black Borders On EGA Monitors
DocumentID: 600454
Revision Date: 29-Feb-96 1:28:25 PM

The information in this document applies to:
WordPerfect® 5.1 for DOS

Problem

Solutions: These are quotes from an article by Paul Somerson, Executive Editor of PC Magazine concerning EGA monitors.

"Borders on the EGA are a problem, and the best way to solve the problem is to convince yourself that an EGA cannot display borders in 350-line modes. When you know something is impossible, it may cease to bother you. You may even learn to prefer the black border. The display arithmetic can prove it to you, and you'll be able to relax knowing that you're not missing out on anything." (p. 730)

The Mathematics of the EGA card work out as indicated in the following paragraphs:

The dot clock on the EGA in 200-line compatibility mode is rated as 14.318 MHz. The dot clock on the EGA in 350-line compatibility mode is rated 16.257MHz. The 350-line mode has 75 percent more lines and only 13.5 percent higher dot clock frequency.

The 200-line EGA mode has a horizontal scan rate of 15.75KHz. The clock rate divided by the scan rate gives 909 dots of the equivalent of 114 characters (8 dots per character) - 80 for the display, 8 for horizontal retrace and 26 for margin area. Divide the horizontal scan rate of 15.75KHz by the vertical scan rate of 60Hz and it gives 262 lines - 200 (25 characters rows by 8 scan lines each) rows are needed for display and about 8 lines are needed for vertical retrace (lower right corner of the screen to upper left hand corner of the screen). The balance could be used for borders.

The 350-line EGA compatibility mode has a horizontal scan rate of 21.85 KHz. The clock rate divided by the scan rate gives 744 dots or 93 characters (8 dots needed for each character) - 80 characters are used for the line, ten characters are used for horizontal retrace - leaving only three characters for margins. The horizontal scan rate of 21.85Hz divided by the vertical scan rate of 60Hz shows that the EGA has the equivalent of 364 lines - 350 lines are used for display and 13 lines are used for vertical retrace leaving only one line for upper of lower margins. To try to show other than a black margin would result in a very faint margin with shading problems in the left two-thirds of the display.

Paul Somerson said that EGABORD.COM can be used to change the margin colors. It is a file available through DOS Power Tools, Techniques, and Utilities. He is quick to add, "However, the results are pathetic. Not only is the border skimpy, but using it causes some shading problems in the left two-thirds of the display. (If your EGA is attached to a regular color display, you don't have this problem. But again, you can only set your border to one of the 16 IRGB colors.)"

Using utilities such as EGABOARD.COM will work until you go into graphics mode such as View Document, Graphics Edit, and Equation Editor. When you exit graphics mode it will reset the screen and the border you have set will no longer appear until you load it again.

Answer:

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