Did you google it before posting this?
It doesn't seem to be so unknown and it kinda looks as if the tape cartridges are still available on amazon, though cannot be shipped to my location.
Onstream 30GB ADR
OnStream 30GB Data Cartridge Tape Drive

Weird - never seen one of those before. Seems to share some design similarities with QIC so presumably shares its flaws too - tension band in direct contact with the oxide layer of the tape that will eventually perish and either glue itself to the tape or fall to bits and lose its ability to advance the tape. Maybe the drive even has the rubber wheel that eventually turns to goo!

Just unknown to me I guess..
certainly not so many for sale ...a bit of a relic I guess.
I just searched and there are a few for sale but tend to be multiples..
I just want 1 for testing...after all ..it may be a faulty drive.
🤣

Found a picture of the inside of an ADR tape cartridge:

Looks like my guess was right - physically it's an incompatible/proprietary variation of the extended mini QIC/Travan cartridge. Will probably turn out to be about as unreliable too as the cartridges and drives age.

I got out my Wang the other day, it was a little dusty from lack of use. I didn't know whether to bother turning it on. To give it a good work out, I'd have to get down and dirty with some SCSI boards, and I never know quite how to jump them, always forget to check their IDs, which can get you in a lot of trouble. Plus I didn't want to buy a potentially shady tape, and have a let down. Then everything is old and wearing out, and you don't know if you'll be waiting all night to completion, and will get your backup.

But the drivebelt looked in good shape, lost it's eject button somewhere along the way though. Probably need to wiggle a pen in there to make the media come out. Stop sniggering at the back, it's a Wang Laboratories tape drive. Not sure what model actually, there are drive rails on it over the label and the screws were frozen (No I'm not saying stiff) enough that I might have rounded out (Not saying strip) the head (okay that was unavoidable) with the driver I had on hand.

A fairly expensive gamble I suppose...but then I was given the drive and 2gb hard drive internally...
but all Wangs aside..
🤣
I am curious...
Found a uk seller with a pack of new sealed tapes x6 ...and made an offer £10 below the asking price..and he let me have them cheap...on account I only really needed 1 for testing purposes.
I suppose he was just happy to shift them.
Also managed to find an ISO image of Onstream Echo..
propriatory software and drives disc...which I have now burned.
No idea of course if this drive is viable...but I can't help being fascinated.
We shall see
rgds
VS