RK07 questions

Tony Duell ard at p850ug1.demon.co.uk
Wed Jan 18 10:26:17 CST 2006

> > Are you sure about that? You can't recover a bulk-erased pack 
> > because you can't rebuild the servo surface, but this drive 
> > has a separate servo surface so there's no good reason why 
> > you couldn't reformat the data surfaces.
> > I've not tried it, though.
> True, just like the RL01/RL02 there is a separate servo track
> on the platters of the RK06/RK07. Indeed, I did try the .FORMAT

No, it's not 'just like the RL01'. The RL's have embedded servo bursts -- 
tht is there are servo signals in the sector header regions of each data 
surface. The same head reads the servo signals and the data.

This is one reason why an RL is so easy to align and why you don't need a 
special alignment pack.

The RK07 has a seperate servo surface. There are 4 surfaces (2 platters) 
in the pack. One surface and its head is just servo signals. The other 3 
surfaces are just user data (and sector headers, etc). 

In an RK07 it's necessary to get the data heads and the servo head 
correctly aligned so that when the servo head is on a track, the data 
heads are too. There are, apparently, 3 special items needed to do this, 
an alignment pack (which contains special signals on the 3 'data' 
surfaces, I assume a bit like the CE pattern used for a floppy drive), a 
tool to screw to the carriage to actually move the heads independantly, 
and some kind of meter to tell you if the heads are off-track. I have 
none of them (yet!).

Since the data surfaces of a normal pack just contain user/OS data -- 
nothing essential for the operation of the _drive_, it should be possible 
to do a low-level format.

> command, but RT11 reported that the command was not available
> for the device, or something like that.
> ".INIT" gave me an error like the ".DIR" command.
> You are correct that you can format the RK07! It does not write
> the servo tracks ("impossible"), but it does write the data *and*
> the headers. However, that format command is not in RT11, but it
> is in XXDP.

Ah, right.... Remember I am a hardware person and deal with gates and 
op-amps :-)

> Edward tried his RK07 last evening, and after he loaded a pack
> (no controller connected at all), he saw the same events (LEDs
> and head movement), but on his drive the READY lamp illuminated.
> I have the field maintenance print set ...

OK. It sounds like your drive is basically working. What I'd do at this 
point is look at the prints to see what should drive the ready lamp. And 
then check back from the output stage until you can find out why it's not 
being turned on. I can dig out my prints and take a look too.


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