RE: CBM900 hard disk timeout

From: Martin Hoffmann-Vetter <>
Date: Fri, 22 Aug 2014 17:35:53 +0200
Message-ID: <004b01cfbe1e$c3248300$>
Hello Michau,

>> So you mean the message above is a "drive initialization failed" and
>> not a "controller initialization failed". This is a good idea! 
> The message actually says verbatim: "Controller/drive initialization
> failed", whatever that means. I get this message in the above cases.
> When I remove the controller, I also get it as the first error
> message.

Then this means "controller initialization failed". ;-)

> A possible hole in my theory is that I see no head movement in the
> hard drive after it initializes. So it would either mean that the
> controller is unable to step the head, or that after initialization
> the head is on the first cylinder so it does not need to move when
> the computer tries to read sector 0x00000002 - could that be the case?

I would say, the drive initialize to track 0. The first sectors are on track 0. This must be the partition table at sector 1. So the real partition starts at sector 2.

> For what it's worth, I also get lots of timeouts when I select the
> "Park drive heads" in BIOS. It's both the same when the drive is
> jumpered as #0 and as #1. I cannot explain that.

So it's possible, the drive can't step to a specified track. This is the difference between ST412 and ST506. ST412 drives used buffered seek. All step pulses are counted and the drive will moved in one pass to the specified track. ST506 drives seek with every step pulse. Is it possible to switch the WD1003 or the hard drive between buffered and unbuffered seek? In buffered seek you need a SEEK_COMPLETE signal on the control port. If the drive don't send it, it's possible the controller detect a timeout! Can you step the drive with pulses on the control port manually? You need a direction signal (low = inward, high = outward - toward track 0), too. After the drive is powered on the READY and SEEK_COMPLETE signals must be active.

>> All hard disk controllers have tolerance, so they are not 100%
>> interchangeable. In the 80, when a ship data with hard disks, i put
>> the passed controller with the hard disk.  
> That's what I'm worried about. Unfortunately the documentation od
> WD1003-CMD is nonexistant. In fact, there is only one mention of this
> controller in Google, besides my posts...

Did you have ask WD?


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Received on 2014-08-22 16:00:02

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