On 2014-01-01 00:52, Jerome H. Fine wrote: The order of dependence on strictly working (and/or accurately emulated) hardware goes: RT => RSX => RSTS. So the fact that something works with RT proves *nothing*! (I've learned this the hard way so many times.) Of course, looked at another way, it's nice of RT to be willing to run on hardware that's not long for this world... ... OR the CSR for the hardware and the device driver do not match. Fortunately, RT-11 allows the user to change the CSR after the boot (for a data device obviously). After that, the user can INSTALL and LOAD. RT-11 also supports UNLOAD and REMOVE if a user needs to power down a data hard drive and physically replace that drive with a different hard drive. This is really especially helpful with MSCP devices. If the user has ONLY the single controller to boot RT-11, VM: can be used to hold the few essential files required by the operating system. At that point, the hard drive on an MSCP device can have the power and cable removed (after the RT-11 UNLOAD and REMOVE) and a different hard drive substituted (followed by the RT-11 INSTALL and LOAD commands). Try doing that on RSX-11 or RSTS/E. 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? :-) Johnny