RL02 Disk Cartridge Problems

From: John Lawson <jpl15_at_panix.com>
Date: Mon Dec 2 21:00:00 2002

On Mon, 2 Dec 2002, Christopher McNabb wrote:

> >
> > How long is a 'while'?
>
> Probably between 30 and 45 seconds. I haven't timed it.
>
> >
> > Is a 'while' the same each time, or is it a variable amount of 'while'?
> >
>
> It is always the same. I think that maybe the drive thinks the disk is
> not coming up to speed fast enough.
>


  I'm not sure what the hardware timeout for bad Tachometer signals is...
but it sure sounds like either the tach segment is munged somewhow (The
ring on the bottome of the platter hub with the slits cut in it) or that
the data on the platter is damaged, or that it was not written on a DEC
system. The packs were used on a number of different systems.



> > Do your working disks function subsequently in the same drives, AFTER
> > you try the bad one?
> >
>
> Yes, once I cycle power to the drive to clear the fault light. I wish I
> knew a cleaner way to reset the fault light.

  Re-boot the computer. At least my 11/44 clears an RL02 fault on re-boot.

>
> > Is there info on the disk you want, or just the platter itself? If the
> > latter case, is there enough time to INIT it before it faults?
> >
>
> The label claims that the disk holds 'Stand-alone Forth', which may be
> interesting. The ready light never comes on, just the fault light, so I
> don't think I could INIT it if I wanted to.

  Yup, that's true: if it never comes into ready, little else can be done.
Do you have any way of knowing what actual System recorded the disk? If
it wasn't a DEC OS, you might have a problem. At the last VCF, I tried to
read two packs that someone had, to see what was on them, and the same
thing happened. (PDP11/44, RSX11M)

> >
> > PS: How much didja pay for it? Just curious...
>
> $9.95 plus $12.50 shipping.

  Not bad, considering what they cost new (around $200).


  With deference to further incoming opinions, I would think perhaps the
data format is completely incompatible, and the drive can't 'find' the
correct bit pattern, and thus it pukes. Tony Duell is familiar with the
internal operation of the RL02, and perhpas he can shed better light.


  Cheers

John
Received on Mon Dec 02 2002 - 21:00:00 GMT