DEC RX50 disks with mystery content

[David Schmidt]

Hello, DEC enthusiasts -

I've got some 5-1/4" disks here that purport to be from a DECmate 
(probably II) and may have data offloaded from a bigger system.  But the 
disks don't have any recognizable trace of a filesystem on them; just 
vast swathes of data that looks like this:

https://drive.google.com/file/d/12EO4Lg1Uh7NvCUJksHQ2AUiK550OX7UJ/view?usp=sharing

It seems to be a pattern of a near-zero byte followed by some other 
byte.  It's like they're storing 12-bit words in 16 bits or something. 
Does anyone recognize this sort of thing, just eyeballing it?

- David