SIMCGA - A CGA SIMULATOR FOR MONOCHROME GRAPHICS CARDS SIMCGA and this document copyright 1987 by C. P. Guzis All rights reserved. Reproduction of SIMCGA or this document is prohibited without the express written permission of C. P. Guzis. ------------------ This is version 4.0 of SIMCGA, released in July of 1987. If you have questions or inquiries concerning this product, please be sure to mention that this is the "July 1987" version of SIMCGA. -WHAT IS THIS PROGRAM?- SIMCGA is a program written for those IBM PC or "compatible" users who have a Hercules Monochrome Graphics adapter card or Hercules-compatible display adapter and would like to be able to run programs requiring the IBM Color Graphics display adapter facility. -WHAT WILL AND WON'T WORK?- Because SIMCGA is a software product, there are certain hardware limitations on its use. Programs which access the Color Graphics Adapter hardware registers directly generally will not operate in a satisfactory manner - the hardware just isn't there to interact with! In general, try running the program - you won't clobber your disks if it doesn't work. SIMCGA will not work with a plain old IBM monochrome adapter or- with an Enhanced Graphics Adapter (EGA). Version 4.0 incorporates support for non-DOS diskettes which con- tain their own operating system rather than using DOS. -WILL SIMCGA RUIN MY MONITOR?- No. SIMCGA programs your display adapter so that the frequencies generated are very much within the specifications of your monochrome monitor. (18.5 KHz horizontal and 53 Hz vertical). However, you should avoid using programs which will cause problems with a Hercules or Hercules-compatible card. Most "screen-saver" programs are in this category and may cause damage to your monitor whether or not you are using SIMCGA. -HOW DO I USE SIMCGA?- To run SIMCGA, copy the programs (all files ending with .COM) on this disk to the directory or diskette where you normally keep your system programs. Then decide if you want to run in "stand- alone" or DOS mode. Standalone mode is used with programs which "boot up" without DOS; many games fall in this category. DOS mode is used with programs which require DOS to execute. In either case, first load DOS. If you want to run a "standalone" program, enter - SIMCGA S means press the "Return" key on your keyboard). SIMCGA will display the product notice and request that a program diskette be inserted into diskette drive "A". Place the diskette containing the program you wish to run in the "A" drive and press any key. The program will be loaded and begin execution in CGA emulation mode. To remove SIMCGA from your computer, turn the computer's power switch off, then on again. A Ctl-Alt-Del keyboard reset will, on most com- puters, also cause SIMCGA to disappear. If you want to run a DOS-based program enter - SIMCGA ( means press the "Return" key on your keyboard). SIMCGA will load its resident part (or tell you why it won't) and set your display to 80x25 color text mode. Your display adapter will appear to be a Color Graphics Adapter board to most programs accessing it. To resume ordinary monochrome text operations, enter - MONO To go back to CGA 80x25 mode, enter - CGA To set 640x200 high-resolution graphics mode, enter - HIRES To set 320x200 medium-resolution graphics mode, enter - MEDRES For most applications, MONO and CGA will suffice to set either monochrome or graphics modes. To completely remove SIMCGA from your computer's memory, enter - RMVCGA Like the standalone mode, the DOS mode SIMCGA will disappear with a Ctl-Alt-Del keyboard reset. If you desire, you may also run DOS as a standalone program. Just insert your DOS diskette when the program diskette is re- quested. -IF YOUR PROGRAM RUNS TOO SLOWLY- Some programs, especially games, require large amounts of atten- tion from your computer. SIMCGA also requires some of your com- puter's attention to keep the display looking good. If you find that there is not enough computer to go around, you may instruct SIMCGA to use less of your machine's resources. However, nothing is free, and the display will exhibit more "ghosting". To change the amount of time SIMCGA "steals" from your application, use a number from 0 to 9 on the SIMCGA command line. 0 tells SIMCGA to use the largest portion of your computer's power to maintain the display; hence programs will run more slowly. 9 tells SIMCGA to use the least practical amount of your computer's power to maintain the display; you will however, see the greatest amount of "ghosting". If you are using SIMCGA in the "standalone" mode, the number may either precede or follow the "S" parameter. For example - SIMCGA 3 SIMCGA S 2 SIMCGA 5S are all forms that SIMCGA can understand. -"IT LOOKS LIKE I'M LOOKING THOUGH A SCREEN WINDOW"- If you're running a program (most likely a game) and you notice that the display has fine black lines running horizontally across it, try using SIMCGA up with the letter "I" on the command line. This has to do with how SIMCGA deals with the timer on your com- puter, but should not otherwise affect program operation. The "I" parameter may be combined with any of the others. For example - SIMCGA I SIMCGA I 2 SIMCGA 3SI are forms acceptable to SIMCGA. -THINGS YOU MAY NOTICE- "Ghosting" of moving graphics images - this is just the way the program operates and is nothing to be worried about. Some lines are thicker than others in graphics mode - SIMCGA fills out the displayed image by "doubling" every other line. -COMPATIBILITY- When you run SIMCGA, you may get a message to the effect that SIMCGA has detected that your monochrome graphics adapter is not CGA-compatible. What this is trying to say is that not all "clones" -accurately- reproduce the functionality of the Hercules monochrome graphics adapter. SIMCGA will attempt to make the best of the situation; however, the simulation may not be perfect in the 80x25 and 40x25 CGA text modes. Gaphics modes will work correctly regardless of the brand of monochrome graphics adapter used. -DISTYPE - DETERMINE DISPLAY TYPE- A utility program for use in batch files is provided for the purpose of determining the type of the current active display adapter. DIS- TYPE may be invoked by the following statement - DISs t vDs^_ZY[XSQRWVf>H@}OHHEGOw6 K76E+w6Kw > KI}+> K ^_ZY[PSQWt>KtKE o .HHK_Y[XPó [ÓSQRVWUEt<K!qK>K>KAKr֋Li9 tk迹A6EE+δ:r8dtBA Ѐ`Kr I:KtANVG!^K=t =tG8uFIEu;E+E¹A us3pAK6K6K&|.u4Q&&DEKEV& `G!N^Y+6KOK:EtK3ɬ uŝ]_^ZY[P/t\KXâKXSQRWVK6K6K6K t:t6K3KtK:Et uKL`< t^_ZY[QRWVRK3Ҁ}:u߀@G!Zr?N!r<KK8:K~KKK <t O!sڠK L ^_ZYWVK u61?ǧuu#5?uu9?uu^_PSQRWVE>E=t.E+A.+ʃ;O?^_ZY[XSQRWVUSH!rDD3EH3EI|$E+&E+&WE+&W O QUIT :EGA GOT EGA, OKAY :CGA GOT CGA, OKAY GOTO QUIT :SETCGA SIMCGA AROUND, ENABLE EMULATION CGA :QUIT COMMON EXIT POINT ----------------------- "Hercules" is a trademark of Hercules Computer Technology; "IBM" is a trademark of International Business Machines Corporation.