Open?

"The format is LTO - Linear Tape Open - but if there is only one media manufacturer then the openness of the media vanishes"

Surely it's multiple manufacturers of the drives, and tape that could be manufactured by other media companies if it were profitable for them to do so, that defines Open?

Closed would be a patented tape format which could be manufactured only with the permission of the patent's owner. (Not including an "open" patent where the owner has agreed in perpetuity that anyone will be given permission to manufacture subject to paying the same pre-agreed royalty as anyone else - CDs used to, and for all I know still do, require a royalty payment to Philips).