MSHERC.COM Mistakenly Loads on CGA Computer; README Addition (69537)






This article was previously published under Q69537

SUMMARY

MSHERC.COM is a Hercules graphics driver supplied with Microsoft QuickBasic version 4.50 and Microsoft Basic Professional Development System (PDS) versions 7.00 and 7.10. QBHERC.COM is the equivalent driver supplied with Microsoft QuickBasic versions 4.00 and 4.00b. You must run MSHERC.COM or QBHERC.COM before you can use Hercules graphics (SCREEN 3) in your Basic programs.

MSHERC.COM or QBHERC.COM should not load on a system that is using a graphics adapter other than Hercules. If invoked on a system using an EGA or VGA graphics card, MSHERC.COM or QBHERC.COM reports the following error and does not load:
Hercules Video Card not present.
Hercules Video Support Routines not installed.
However, on some systems using CGA graphics cards, MSHERC will load into memory and display the following:
Hercules Video Support Routines installed.
This behavior consumes memory unnecessarily, and the message can be misleading because Hercules graphics (SCREEN 3) does not work on CGA systems. MSHERC.COM or QBHERC.COM should not be run on computers that have a CGA card.

README.DOC Addition for MSHERC.COM

All documentation for the driver file MSHERC.COM was mistakenly left out of the manuals, online Help, and README.DOC file of QuickBasic version 4.50 and Basic PDS versions 7.00 and 7.10. MSHERC.COM is briefly mentioned in the packing list (PACKING.LST) of these products, but instructions are missing.

The following instructions for QBHERC.COM are taken from the README.DOC file for QuickBasic versions 4.00/4.00b and Basic compiler versions 6.00/6.00b; this information applies to both QBHERC.COM and MSHERC.COM:

The SCREEN statement now includes mode 3 for Hercules display adapters. The following is a brief summary of screen mode 3. See your Hercules documentation for details.

QuickBasic supports Hercules Graphics Card, Graphics Card Plus, InColor Card, and 100% compatibles.

You must use a monochrome monitor.

Hercules text mode is SCREEN 0; Hercules Graphics mode is SCREEN 3.

You must load the Hercules driver (QBHERC.COM) before running your program. If the driver is not loaded, SCREEN 3 statement gives an "Illegal function call" error message. Type QBHERC to load the driver.

Text dimensions are 80x25 (9x14 character box); bottom 2 scan lines of 25th row are not visible.

Resolution is 720x348 pixels, monochrome.

Number of screen pages supported is 2.

The PALETTE statement is not supported.

In order to use the Mouse, you must follow special instructions for Hercules cards in the Microsoft Mouse Programmer's Reference Guide. (This must be ordered separately; it is not supplied with either the QuickBasic or the Mouse package.)


Modification Type: Minor Last Reviewed: 1/9/2003
Keywords: KB69537