On 2013-05-17 21:08, Bob Armstrong wrote: Unibus VAXen basically means VAX-11 machines. They booted either from VMB on console media, or (for the 11/750) from a boot block. TO be fair, the limitation on booting was mostly just that nobody bothered to implement support for any other device in VMB. It wasn't any kind of hardware limitation. True. As long as you actually even used VMB to boot, which only VMS did back then. VMB did eventually add the capability of booting Unix as well, but that was later. So Unix booted without VMB. Also, the VAX-11/750 do not even use VMB... Later versions of VMB (e.g. in a MicroVAX) could boot directly from various tape devices. Right. Really? Not from tape? Interesting design choice... Old VAXes booted standalone BACKUP from the console media (TU58 or RX01). SA BACKUP then could talk to tape drives just fine. It's all you need to install VMS, so that was all they did. Yes. And of course, nobody ever wanted to boot anything but VMS... ;-) Johnny