Path: utzoo!attcan!uunet!seismo!sundc!pitstop!sun!decwrl!ucbvax!phast.phys.washington.EDU!SEYMOUR
From: SEYMOUR@phast.phys.washington.EDU
Newsgroups: comp.os.vms
Subject: chaining RD-disk drives
Message-ID: <8805161326.AA15631@ucbvax.Berkeley.EDU>
Date: 13 May 88 20:43:00 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 21

(wait a minute... that's an internal DEC address! what gives?)

to the best of my knowledge, you CANNOT simply "chain" RD-drives
(thanks, DEC).  you need an  RQDXE-AA  or -FA   $250 in last fall's
decdirect catalog.  the -AA is for internal expansion (drive in
same BA-cabinet, -FA is external (drive in external box)).

i've got an -FA -- there are a fascinating number of parts on it.
"it" is a dual-wide card that sits in your host cpu box.  it uses
power but does not need other Qbus signals, so it need not be in
the proper "next-slot" that a REAL Qbus member would occupy.
lots of jumpers to play with (took our installer about three tries).

the inability to "chain" the drives is probably connected with the
inability to use plain-jane (i.e. cheap) ST-506 drives.  rumor has
it that the RD-family has the "seek controller" chip on the drive
(instead of making the master controller card do it).  there are
foreign vendors for RD-equivalents, at about 60% of dec cost.
they might also have RQDXE clones, but at $250 it's getting too
cheap to bother.
-- dick seymour   seymour@uwaphast.bitnet