You mean the old "Caddy Drive" units.
I use an old 486 running 4 x GB HDs as a slave unt hooked up through a parallel cable to one computer here via interlink. The slave drives appear as I:, J:, K: and L: on the main computer.
At one company I rigged a timed Archiver to back up all the ECAD work to a Caddy Drive and the boss would take it home and unpack the archive into his computer's Drive D:
All the computers in the facility had ECAD work from my department stored on them. When it comes to backup, paranoia rules!!
When I was a University, back in 1996 as a mature student, I hacked the engineering house network and backed up all my coursework as multiple password encrypted hidden archives on every server and 120 PCs on the electronics engineering floor. And all right under the noses of the IT guys, who I was on speaking terms with.
If you are going to hide data on someone else's system or computer, use an encrypted hidden archive and it will be totally invisible to IT folks.
If you want to back up key files from a network, or just want to hack certain files, use an archiver, write the "target list" to include all the desired files, set it to search all drives and servers recursively. It will copy locked, uncopyable and alarmed files. (I'm probally frightening IT security guys here!!)
The files structure is preserved and cloned when unpacked on another computer. Yes, it will even copy licences!!
I've found that using an archiver is the quickest and most secure way of backing up key files for a system. To set the back up sequence in motion, one just clicks on the ICON and just leave it to it.
Yes, I use old HDs for storage as well.