RK11-D "diskless" test ZRKJE0???

Nigel Johnson nw.johnson at ieee.org
Thu Jul 9 19:15:05 CDT 2020

The error signal was wire-or'ed through up to four drives, so it must be
terminated somewhere - IIRC there was a Unibus terminator in the last
drive, but it has been 45 years since I worked on them, the little grey
cells are fading _\:-)

cheers, Nigel

Nigel Johnson, MSc., MIEEE, VE3ID/G4AJQ/VA3MCU
Amateur Radio, the origin of the open-source concept!
Skype:  TILBURY2591 nw.johnson at ieee.org

On 09/07/2020 20:02, Robert Armstrong via cctech wrote:
>   I have an 11/04 with an RK11-D.  I have a couple of RK05s, but I
> wanted to test the controller before I start working on the drives. 
> The PDP11 Diagnostic Handbook says that ZRKJ?? "checks only the
> drive-independent logic of the RK11 controller. no drive is
> needed..."  I assumed that meant it was a diskless test, but now I'm
> not sure that's true.  Can anyone confirm or deny this? Does anyone
> have a listing of ZRKJE0?
>   My RK11-D has the BC11 drive cable plugged into the backplane, but
> the free end of the cable is just lying on the floor.  No drive is
> connected.  The test fails with
>       PC   REGADD    RECVD
>     002560  177402  100000
>  177402 is the RKER register and bit 15 is DRE - "Drive Error".
> According to the manual this bit is set when the AC power to the drive
> is lost, which given that I don't have a drive at all, doesn't sound
> unreasonable.  Continuing ZRKJ?? also gives
>       PC   REGADD    RECVD
>     002560  177404  140200
>       PC    WROTE   READ
>     002636  000002  140202
> 177404 is the RKCS register and the first two bits are ERROR and HARD
> ERROR.  These are both set by the DRE bit in RKER and aren't really a
> surprise.
>   I'm starting to wonder if this diagnostic really works w/o a drive
> attached, or if these errors are expected.
> Thanks,
> Bob

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