Cream of the Crop 1/Cream of the Crop 1.iso/EDUCATE/PCLEARN.ARJ/PCL.LZH/DISPLSTD.TUT

Text File | 1991-04-02 | 8KB | 141 lines

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               DISPLAY STANDARDS - WHY SOME PROGRAMS WON'T RUN!

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       All beginners must at some point learn the compatibilities of
       software, the monitor and electronic video display circuits
       (sometimes called "cards") attached to a computer. Your monitor
       is usually matched to a video circuit board within the computer.
       You can change the monitor and video circuit board to add color
       or upgrade to higher resolution color as you wish. The computer
       remains the same but the visual clarity changes!

       Many software packages allow several types of display in color
       or monochrome with varying degrees of resolution. These types of
       displays are listed below. Remember: both the monitor and the
       video card within the computer determine the type of color (or
       lack thereof) which you see. Color quality can be changed by
       buying a different monitor and replaceable video circuit board.

       MONO or MONOCHROME refers to text (characters, letters and
       numbers) on the monitor screen. A monochrome screen is typically
       manufactured to produce green or amber letters on a dark field.
       This type of monitor is usually mated to a monochrome circuit
       board (card) inside the computer.

       HERCULES is a reference to a high resolution monochrome circuit
       board or card. Hercules circuits usually drive or operate a
       monochrome monitor. By itself a Hercules circuit card CANNOT
       drive a monochrome monitor when you try to run a COLOR software
       package. Low priced computers frequently have Hercules display
       resolution and may have trouble displaying color games or
       graphics software which try to output color on the monochrome
       Hercules circuit. Result: no display. Solution: obtain alternate
       software or purchase a true color monitor and color video
       circuit for the computer.

       CGA (color graphics adapter) refers to low resolution color
       displays. Color monitors and CGA circuit boards (cards) are
       usually mated together in this scheme. Alternatively, CGA color
       circuits can operate a monochrome monitor, but results can be
       unpredictable depending on the software program. Some color
       software programs produce faint or flickering images when a CGA
       color circuit operates a monochrome monitor. Of course, when a
       CGA circuit card operates a monochrome monitor, only black and
       white images can be seen.

       EGA (enhanced graphics adapter) is high resolution color
       circuit. The EGA card typically operates or drives a special
       high resolution EGA monitor or "multisync" monitor.

       VGA has still higher resolution and requires a still higher
       performance monitor. VGA color monitors are somewhat expensive,
       but many owners opt for a VGA monochrome monitor screen which is
       quite affordable if high resolution is desired, but color is not
       necessary.

       Curiously most display schemes are "downward compatible". This
       means that a high end VGA card can, through software command, be
       switched downwards into EGA and even CGA or Hercules modes.
       Ponder this for a moment: if you own a high end VGA or EGA
       display system you can "downshift" to display CGA and possibly
       Hercules monochrome resolution. This is helpful when the
       software you are using will only display up to CGA resolution,
       for example. Many utilities are available to help you set the
       color spectrum and output quality of EGA and VGA display
       circuits. And there are other standards even beyond VGA display
       resolution, of course.

       The bottom line: most low end PC compatibles contain circuits
       for monochrome and frequently either CGA or HERCULES resolution.

       Some computers contain circuits for only CGA. The trick is to
       determine what display standard you have and use software which
       will work with that display resolution. Of course you can always
       upgrade to a higher standard later by swapping both the monitor
       and display card. Ask your computer salesperson what type of
       graphics adapter or display system your computer contains.

       Owners of CGA (color) circuit board computers who have only a
       monochrome monitor can sometimes improve software display by 1)
       slightly increasing screen brightness with the monitor
       light/dark control but be careful! 2) using the DOS mode setting
       to switch the CGA circuit board to its black and white output
       (example: mode bw80). 3) Searching the software instructions for
       resetting the software package itself to display in other color
       shades which can be seen clearly on the monochrome monitor.

       Owners of hercules circuit boards who wish to use CGA or color
       software can try loading and running several small software
       emulation programs which try to help a Hercules or monochrome
       display card work in CGA color mode. This is a "poor man's"
       solution or "workaround" which let's you display color software
       on your Hercules or monochrome monitor!

       Of course you will only see shades of gray, but at least the
       software can display on the screen. Examples of these types of
       emulation programs for Hercules cards include the shareware
       program SIMCGA.COM and CGA.COM. Some slight screen flicker may
       be apparent when using these CGA emulation programs, but this is
       an inexpensive way to help a monochrome hercules circuit display
       the many color software programs on a monochrome monitor. CGA
       software usually consists of games and some color graphics
       programs which won't display or display poorly on your
       monochrome monitor. The idea is that sometimes inexpensive
       emulation software can "patch" or make up for a lack of display
       hardware.

       If you wish, you can purchase additional plug in circuit boards
       to "upgrade" your computer to these ever higher standards of
       display clarity. Example: CGA circuit owners can add an EGA
       circuit card which displays EGA, CGA and Hercules modes. For the
       most part monochrome is satisfactory for office use, Hercules is
       adequate if you need to do graphing, CGA is useful for games and
       other types of color graphing. Some computers are equipped with
       several circuits built in (monochrome, hercules and CGA) but you
       need another monitor to use all the circuits! Some owners find
       that their computer contains an EGA card, for example but they
       only have a simple monochrome monitor. The upgrade path here is
       simply to replace the monitor to allow the higher resolution
       modes contained within the circuit card to be displayed.

       Final thought for the bewildered beginner: find out from your
       instruction book or computer salesperson which video circuits
       (CGA, Hercules, etc) are contained in your computer. Determine
       which type of monitor you have. Finally check software purchases
       to be sure the software package will match or mate to your
       equipment and display properly. Consider purchase of an
       additional display circuit card if the software you need or use
       does not display with your computer. In most cases, set
       priorities. If you use the machine mostly for office use,
       monochrome or Hercules text mode is fine. For more sophisticated
       design, graphics or use with games, color adds clarity.

       One the contemporary computer scene, a minimum for today's modern
       software is at least EGA color circuit and appropriately matched
       EGA color monitor.