I previously posted under the subject "IOATAController device blocking bus" in the Mac OS X 10.x forum, but some recent info has come to light which makes me think I need to redirect it here.

I've had a problem for a while now where periodically the system will freeze for like 15 secs or so with the spinning wheel. I can switch to other open apps but if I select something there the wheel will spin in that app too. No apps can be launched during this either. After I the spinning wheel stops the system then catches up and apps launch if I clicked on them previously. I check the console and see the following:

localhost kernel: IOATAController device blocking bus.

This is time-stamped at the same time the freeze occurs. The last 2 times it happened I noticed that it was exactly a half hour apart which made me think of my TechTool Pro SMART tests. So I went and checked and the last test was run at exactly the same time as my freeze to the very second. I have 2 drives on my ATA bus and I did notice something else odd with the SMART tests. Even though they're set to run every half hour the timestamp in techtool shows that they're not.

Here's the last sequence of events and what was checked as far as I can tell.

12:16:33 AM Slaved drive was checked. Don't know if my Master drive checked since there's a later timestamp for it.

12:47:32 AM localhost kernel: IOATAController device blocking bus --- appears in console and I have a freeze. The above Slaved drive does not have a later timestamp than 12:16 AM so Techtool didn't report doing anything. The Master drive may have check but again I have a later timestamp for it.

01:17:32 AM localhost kernel: IOATAController device blocking bus. --- another freeze with the same error in console.

01:17:32 AM Master drive reports SMART pass in techtool and Slaved drive still has the 12:16 timestamp.

I'm running 10.3.3 on a Dual-1GHz Quicksilver with 1.5 gigs of ram. My hardware test cd passes and S.M.A.R.T. tests on the drives pass. Diskwarrior and Techtool don't report any problems and my permissions are good.

Could Techtool be having a problem when running SMART tests with drives that are on the same ATA bus and slaved to each other? The slaved drive may even have been spun down during the freezes and may be key to the issue. I have noticed that I don't seem to get the freezes when I'm playing iTunes tracks throughout the day which are stored on my Slaved drive.

Also, don't know if this is important, but my Slaved drive is listed first in Techtool's smart window with my Master following it whereas all the other tests listed my Master first with the Slaved drive following it.

Anyway I've since disabled the SMART tests in Techtool and turned the one's Diskwarrior supplies back on and in the last hour I haven't had a freeze nor an error in my console.

Thank you for your clear and detailed report.

We have had one other report of similar symptoms when a S.M.A.R.T. test is scheduled to take place, and the supported ATA/IDE drive is sleeping while the Macintosh itself is not.

I would appreciate it if you would send a copy of your posting and a text copy of your Apple System Profiler report to us through our new Web-based support at http://www.micromat.com/registration/index.ws . If you registerd TechTool Pro before February 18, 2004, a user ID and password has already been created for you, and can be sent to you by e-mail. Thank you.

OK, I've sent the info you requested at your support form.

Thank you.

I hope the details you provided will make it possible to reproduce this problem and solve it soon.

Kevin, what make and model drive is the drive that is causing the stall? I ask because I believe I am the one other report that MMT3 is speaking of. In my case, drive is a 30 GB Maxtor 53073H6. The freeze only occurs when the drive is sleeping. If it is active, the test runs without a hitch.

Mine's a Western Digital 80 Gig so that seems different enough.

HI,

i just found your post searching for "IOATAController device blocking bus". My ibook won't boot anymore, not even from CD. In verbose mode it gives this message followed by "Still waiting for root device" repeating endlessly. I have just changed my hard drive after the old one had died. I installed Panther and everything seemed fine. Now, everything's a mess... again. Please, if anyone has any info on what these messages mean exactly, post it here.

Thanks
JV

When you boot from your Mac OS X Installer CD, TechTool Pro 4 sitting on the hard drive (if you have it installed) cannot be the source of the error message.

Do you still get this message if all peripherals are disconnected before you begin the boot from the CD?