🚀 go-pugleaf

>I have heard some of this before, all too fuzzy though.
>
>I have seen actual DEC RD51 drives that come with metallic cutable jumpers on 
>the DS lines.  DS0, DS1, DS2 are intact and DS3 is cut.  This means that this
>particular drive will select on 0 or 1 or 2 but not 3.  I have been told that
>the reason for cutting the DS3 line is that in (presumably one of the PRO
>models, because it ain't a DECmate or RB), the controller uses the incompatible
>notion of *reading* back DS3 instead of potentially asserting it.  Thus, a
>5 Meg has the DS3 set and a 10 Meg has it clear, so the machine "knows" what
>size disk it is.  (This is back when there only were RD50 and RD51 supported.)
>
>Is there anything to this?

I don't know.  I can only mention what my docs have.  The Pro pocket service
guide says to cut the "fourth from the back of the drive" jumper.  They've
used a seven jumper dip leaving the 8th (toward the front of the drive) empty.
I don't have the Seagate info to know what the jumpers do.  My old uVAX-1
docs say to cut the back two and the fourth (as for the Pro).  I've forgotten
what the setting for the RD50 is, possibly all jumpered.