RSX can boot from virtual devices. Also, you can load and unload device drivers in RSX, but you don't normally do that just to bring devices offline or online. That is a separate operation from loading and unloading device drivers. But yes, if you want to disconnect devices, buses, CPUs or memory, you can do that just fine on a running RSX system. And bring them online again later, if you want to. Any other trick you'd like to do? :-) While it is extremely unlikely that I will ever run RSX-11, the above ability surprises me. Please clarify to make sure that I understand. It is my impression that RSX-11 requires all device drivers to be LOADed at boot time and always be kept LOADed. TSX-Plus has this requirement and I guess I assumed that RSX-11 was similar. Based on your information, I understand that RSX-11 does support a device driver UNLOAD and REMOVE commands (or whatever syntax is used in RSX-11 since I just used the RT-11 syntax). So please confirm. In respect of RSTS/E, is this possible as well or does RSTS/E have the same requirement as TSX-Plus? Jerome Fine