Burroughs BU4400 tape drive. What is it?

[Mike van Bokhoven]

Hi all,

I just bought this Burroughs BU4400 tape drive:
https://www.trademe.co.nz/Browse/Listing.aspx?id=1999913439
As the seller says, Google comes up empty. Seems strange, I would have 
expected some reference somewhere. Does anyone know anything about it? 
I'm going to pick it up this evening. It'd be superb as a display piece, 
but I'd be really keen to drive it with something and get it reading and 
writing.
On that topic, are there any suggestions on how I could get my hands on 
a few tapes, preferably with a format this drive can read? The actual 
contents aren't important; even blanks would be OK, though not being 
able to get it reading before moving on to writing would make the 
project more difficult.

Cheers,
Mike