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Conference noted::hackers_v1

Title:-={ H A C K E R S }=-
Notice:Write locked - see NOTED::HACKERS
Moderator:DIEHRD::MORRIS
Created:Thu Feb 20 1986
Last Modified:Mon Aug 03 1992
Last Successful Update:Fri Jun 06 1997
Number of topics:680
Total number of notes:5456

94.0. "Hacking the hardware" by EAYV05::WESTON () Tue Feb 12 1985 12:22

Has anyone come up with a way to use RD50s (plus PC interface) in Q-bus 
machines?

Having upgraded the small RD50 in a PC some months ago I have it sitting
under my desk. Meanwhile I have this personal 11/23 strangled with RX02s...
Seems such a waste. If only I knew how to rework the PC board to sit on the
Q bus and look like a RQDX1 to the system....?? 

John
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94.1ERLANG::CAMPBELLTue Feb 12 1985 14:1112
The QDA, or whatever they call the thing in a Microvax that talks to the
RD52, should work just fine talking to an RD50.  All the RD5x drives
are ST-506 (or ST-412) compatible, and the controllers talk standard
ST506/412 stuff out their cables.  That also means you're not restricted
to DEC drives;  if you've got sources to the driver (or are brave about
patching binaries) you can stick some of the really whizzy ST506 drives
on the market into our PCs.  (Micropolis makes some really fast drives
that retail for what employees pay for DEC drives!!  And they're twice
as big, half again as fast...)

- Larry Campbell
  Eastern Research Lab (Hudson)
94.2FKPK::KONINGTue Feb 12 1985 14:1723
There's no way in h*** you're going to be able to use the RCD50 controller
on a Q-bus machine, and even if you could modify it there'd be no point
since it's about as inefficient a disk controller as one could possibly
design.

I don't share Larry's optimism about hooking the RD50 to an RQDX1 (QDA is
for SI disks like RA80 -- and it's now called KDA50-Q).  The microcode
in the controller knows about the sizes of disks; for RD52 support they
had to add a microcode ECO, and then it only handles specific disks; for
example the original RD52 candidate by Evotek is slightly smaller than
the "real" RD52 and is not supported by the standard controller.

So I doubt that you'd be able to get the RD50 to work unless you ECO
the microcode once again.  But if it does work or can be made to work,
you're all set -- no host software changes needed since this is an
MSCP controller so the driver just expects the controller to tell it
about the size of the disk.

If you do get this to work, please let us know -- just the other day
I gave someone else this same pessimistic message, so if I'm wrong I'd like
to be able to tell others...

	Paul
94.3EAYV05::WESTONThu Feb 14 1985 11:574
Anyone got the microcode listing, together with the ECO done for the
RD52?..... 

John
94.4FKPK::KONINGThu Feb 14 1985 17:421
You might talking to Ric Perron (cache::perron); that's his code.
94.5EAYV04::PETERMSat Feb 16 1985 17:237
	
	I have a PC380 that won't work with an RD52.  The RD52 and it's
	controller have been substituted with no joy.  It works fine with an
	RD51.  FS are lost on it too.  Is there a jumper on one of the 
	boards that says "Hey guy! That's an RD52 out there." ? 

PeterM
94.6SERPNT::GULDENSCHUHSat Feb 16 1985 18:177
Try posting this question in EVE""::SYS$NOTES:CTNOTES.  That's the PRO
support and developement notes file.

In fact, the answer may already be there.  I remember seeing several notes
on RD52's, but can't remember the specifics.

/s/ Chuck
94.7SNOV10::QUODLINGSun Feb 17 1985 22:125
RE .5

Are you sure that you have the right controller... The 54-Class Part no for an 
RD52 pro controller is the -01 variant of the RD50/51 controller.
Q
94.8AMBER::KAEPPLEINFri Sep 20 1985 18:3415
I was visiting this file and the tile reminded me of a hardware hack I've
done many times.  It was done initially for some TOPS-20 CAD machines in
Marlboro with color display terminals.  I might as well document it.

DH-11's can run at 19.2kb.  Find a print set and the clock board.  Find
a clock rate for 19.2 (I forget where it is - on one of the counters)
Cut the etch for some useless rate (ie 7200, 50) and wire the new rate
to it.  When you want 19.2k, tell the software to use the old speed
(hack predates 19.2k autobaud, and this IS a HACK).

Field service probably won't notice for a long time, but I told them
anyway and they didn't seem to mind.

Mark