With LPT in EPP (or, for that matter, ECP) mode, "synchronicity" is ensured by hardware, so Windows has little chance to **** things. However, as LPT (as well as COM) are "deprecated" by M$, there ARE issues with drivers, compatibility etc. At least, the drivers are not always able to switch the LPT port circuitry (usually part of a SuperIO-type IC) to the required mode (there is no explicit way in the WinAPI to do it), so one has to fool around in BIOS setup to get it right. But that's the usual way to do for DOS, too, as there are too many SuperIO chips around with mutually incompatible ways to set them up (and, each BIOS is written specifically for the chip which is present in that PC).

JW