CALCAP® System Requirements

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Windows or MS-DOS PC or 100% compatible with 80286 or better microprocessor; 512K free memory; Hard disk with 2 MB free disk space; 80-column color display (CGA, EGA, or VGA color monitor, or Active Matrix color laptop); MS-DOS 3.1 or greater.

Technical Information

Stimulus materials are presented using standard Windows or MS-DOS-compatible Personal Computers (Intel 80286 or faster) and IBM-compatible CGA, EGA, VGA, or XGA color displays. The program automatically calibrates itself to adjust for differences in CPU clock speed, monitor timing, and keyboard response in order to provide uniform timing across multiple computer systems. The timing circuits have a minimum resolution of 0.70 msecs for timing of the materials displayed on the screen, and a minimum resolution of 1.34 msecs for detecting keypress responses from the subject. The hardware that controls the color monitor rewrites the screen image sixty times per second which means that there is a potential timing error of up to 34 msecs during which the stimulus image is written on the screen (17 msecs) and subsequently erased from the screen (another 17 msecs). The CalCAP program checks the position of the electron scanning gun prior to writing on the screen, thus reducing actual error variance to 1-2 msecs.

IMPORTANT NOTES: The CalCAP may be incompatible with some laptop computers that automatically adjust their clock speed. If you notice radical changes in timing of the stimulus materials in the middle of the task, you may be able to permanently set your clock speed through the laptop BIOS or SpeedSwitchXP Software ( or by changing your laptop power settings to maximum performance.

For more information, contact Eric Miller at

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