The .bck format does not mean that it is bootable by a emulated tape device, and it is definitely not a tape image format that emulated tape drives will directly support.
Hoffman labs has some documentation for making bootable tapes. It is probably the hardest way to make your .bck bootable if it is even possible. http://labs.hoffmanlabs.com/node/922
The method that I would use is to create a SimH system with two disks and a CD-ROM.
Mount VAX/VMS CD-ROM image on the CD-ROM, boot it and install it.
Configure TCP/IP on the installed system, and then FTP the BCK file.
Fix up the save set file parameters, and then use backup to restore it to the second disk, and then boot the second disk.
Current SimH is found at https://github.com/simh/simh
The users guide is at: http://simh.trailing-edge.com/pdf/simh_doc.pdf
malmberg June 26 2018 https://www.openvmshobbyi st.com/forum/viewthread.p hp?forum_id=10&thread_id= 2363
bhamakripa June 24 2018 I am trying OpenVMS via SIMH. Need to get OS binaries for v7.3. Registered here but don't have any membership number yet which is needed to get license. Pls suggest what to do. I hardly know anyth
basilh June 05 2018 Any other forum members in Perth, Australia?
malmberg March 24 2018 Probably. More people hang out on the comp.os.vms newsgroup.
vaxpert March 23 2018 I have a PE42A and other Alpha system stuff for sale. I'm in So California. Any interest out there?
goodbyespy February 27 2018 To Prohorenko. Please, visit group OpenVMS in the ok.ru
peteherrera February 24 2018 How much does it cost to buy a complete OpenVMS hardcopy documentation set of the latest version
prohorenko February 17 2018 Please help to obtain the license on OpenVMS
malmberg December 12 2017 HPE only makes the most current version of OpenVMS Alpha / IA64 /VAX available to hobbyists. When I had access to the Alliance 1 program it was the same. No public downloads are allowed by HPE.
nmbonao December 08 2017 Is anybody knows OpenVMS 8.2 version downloadable version? or CD copy? Thank you very much
aarommes December 02 2017 Bitcoin and Blockchain enthusiasts ( plus distributed computing ) please connec / reply: http://www.openvmshobbyis t.com/forum/viewthread.ph p?forum_id=130&thread_id= 2991
malmberg September 10 2017 https://sourceforge.net/p /vms-ports/wiki/VMSInstal lation/ For the most part just use VMS 6.1 media instead of 7.3. But why run the older release?
DoeveR August 07 2017 Where can I find the write up on running VMS 6.1 using the simh emulator?
Bart March 20 2017 Happy to have found my password again!