 | Author: | VMAXX (registered user: 6 posts ) |
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| Date: | Fri, Feb 25th, 2011 @ 04:26 ( . ) |
If the code has been patched, some version of V-Max around that time had a self-check built in which calculated a check sum, and if it failed to match the expected value, decremented the stepper motor minimum delay value, until the stepper motor routine pulsed the head too quickly, eventually resulting in one or more missteps when moving track to track. Which would result in random load errors in the copies... Such self checks could be buried in any sector, since sectors often would overload the last byte of the load routine with their own RTS instruction, unless they were copy protection sectors. One failure to pass the check sum routine wouldn't cause a load failure, it took repeated failures to decrement the delay value past the physical limits of the stepper motor itself. |
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