RK07 questions

Tony Duell ard at p850ug1.demon.co.uk
Tue Jan 17 14:46:47 CST 2006


> 
>   Hi all,
> 
> I am working on the last peripheral device connected to
> my 11/34, two RK07s.  This will be my first experience
> with RK07 drives, so I have a few questions.
> 
> I installed the RK611 in the system (in an expansion box)
> and made sure that the UNIBUS is OK. The 11/34 starts, and
> I can boot RT11 from DL0:. ".SH DEV" shows that the DM.SYS
> driver is installed. However, after loading a pack the RT11
> commands ".DIR DM0:" or ".INIT DM0:" report an error.

What error do you get. IIRC the RK07 pack can be formatted (this does a 
low-level format of the data surfaces). You need to do that before 
INITing in most cases.

> I must say that the READY light did not turn ON on the drive.
> I switched the 11/34 OFF, because I think I need to take a
> closer look at the RK07 drive itself first.
> Here is what I did and saw.
> 
> I removed the metal cover at the top-rear side. Now you can
> see the big magnet and the head assembly.  I first checked

You can also swing the card cage assembly twards the rear of the drive. 
Make sure you have the cables connected correnctly (IN and OUT are not 
the same on these drives -- the controller must connect to an 'IN' 
connector, the terminator to an OUT connector. Unless you have a 
dual-ported drive, use the 'A' connectors, make sure you have the 
interface card in the right slot of the cardcage, and press the 'A' 
button on the front).

On the top of some of the boards are LEDs. The plastic cover over the 
boards identifies them. What do they do at spin-up?

> the "emergency retract" mechanism.  When you push down the
> lever that locks the heads, and gently push the head assembly
> forward toward the cartridge compartment, the heads are pulled
> back as soon as the little microswitch is (dis)engaged.

OK so the 9.6V NiCd under the chassis is still good.

> Then I loaded a pack and pushed the LOAD button.
> After some 20 seconds the disk has spun up (I assume), because
> the heads start to move.

You should hear the spindle motor start running. Mind you, if it wasn't,  
you'd get some very nasty noises when the heads moved.

> The heads first move at a moderate speed toward the centre of
> the cartridge (I would say a full travel), stop, and then move
> back at that same speed, but not completely to the home position.

I think that is correct. The heads do a full seek to the inner guard 
band, then return to cylinder 0.

> Again, I *assume* that the heads detected track 0 and stay there.
> However, the READY lamp does not go ON.  It could not, because
> the lamp was defective :-)  After replacing the lamp with a
> checked-good lamp, I repeated the exercise.  The heads show the
> same movement, but the READY light stays OFF.
> 
> 1. Is that head movement behaviour correct?

I think so.

>    I will try to make a movie of the movement this weekend ...
> 2. What would the head movement be if the pack was bulk-erased?

I would think they'd go towards the spindle and then return to the 
unloaded position as the drive wouldn't find any servo information at 
all. 

I've not tried this, so don't blame me if the heads run into the spindle 
or something horrible, but you could unplug the servo head from the servo 
preamplifer and try again. With no servo signals at all, you'd be 
simulating a bulk-erased pack. Look for a change in behaviour.

IIRC there are 4 heads in the RK07. All 4 head cables plug into the 
read/write board, but one of them has another connector coming from it. 
That's the servo head. The 'connector' on that head on the R/W board is 
just to anchor the cable, it's the end-of-cable connector that plugs into 
the servo preamplifier that you might disocnnect.

> 3. Should the READY lamp go ON?

I think so, but it's been a long time.

> 
> An other thing I noticed.
> As the 11/34 is OFF, there is no controller connected to the
> RK07 drive. OK, it is, but not powered.
> With the RL drives the FAULT lamp will be ON if the controller
> is not powered. Is this the same for the RK07?

No, an RK07 will spin up and load the heads without a controller. No 
FAULT lamp.

-tony




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