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Revisiting Panther’s FireWire Data Loss Problem

When Apple released Mac OS X 10.3 Panther last October, many people (though by no means all) had serious difficulties with their FireWire hard drives. Affected users found that, after restarting their computers under Panther with the drives connected, the drives become completely inaccessible – unable to mount on any operating system, and so badly damaged that even disk recovery applications could not retrieve their data.

Not long after the problem surfaced, Apple acknowledged an issue affecting FireWire 800 hard drives that use the Oxford 922 bridge chipset with firmware version 1.02 or earlier. Manufacturers of such drives quickly released firmware patches, and Apple took steps to resolve the problem from their end as well. The Mac OS X updates (beginning with 10.3.1) provide "improved reliability" with FireWire 800 drives, though Apple still recommends that you update the firmware on such devices. (See "Fixes Available for Some Panther FireWire Troubles" in TidBITS-704 and "Apple Updates Panther to 10.3.1" in TidBITS-705.)



Data Loss with FireWire 400 Drives — All this is old news to most TidBITS readers. But for the past several months, users of FireWire 400 drives have wondered whether they can safely upgrade to Panther yet. Neither Apple nor hard drive manufacturers ever officially acknowledged a data loss problem with FireWire 400 drives, yet a number of users, including at least one Take Control author, have experienced exactly the same symptoms with some FireWire 400 drives. Although the root cause appears to be different – and the problem less widespread – the data loss, when it occurs, is no less serious.

Whereas the FireWire 800 problem was easily reproducible, failures of FireWire 400 drives seem to be random. A given drive model may work correctly on one machine and fail on another that appears to be configured identically. In general, the reports I’ve read show a higher tendency for problems to occur on systems with multiple FireWire devices chained together or attached to a bus-powered hub, especially if one device is an iSight camera. (Apple’s iSight 1.0.2 update may fix this.) Also, drives that support both FireWire 400 and 800, or FireWire 400 and USB (1.1 or 2.0) appear to experience problems more frequently than drives that support only FireWire 400. Lastly, computers that support FireWire 400 but not FireWire 800 are typically less likely to experience this problem.

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I’ve laced my description with fudge words such as "seems," "tendency," and "typically." Unfortunately, none of the experts I consulted knew what causes this problem. Drive manufacturers have spent countless hours testing without reaching any conclusive results. And thousands of users – including me – never had a problem with their FireWire 400 drives (from a variety of manufacturers). Even so, the iPod is the only FireWire 400 device I know definitively to be immune to this problem.

Recommendations for FireWire 400 and Panther — In version 1.1 of "Take Control of Upgrading to Panther" last November, I recommended against using FireWire 400 drives with Panther until more was known – or failing that, to be sure the drive was never connected when the computer started or woke from sleep. Given the relatively infrequent occurrence of this problem, I feel comfortable tempering my suggestions somewhat.

If you want to upgrade your computer to run Panther while continuing to use a FireWire 400 drive, follow these guidelines:

  • Back up everything on the drive to DVD, CD-R, tape, or some other medium other than another FireWire hard drive before installing Panther.

  • Check your drive manufacturer’s Web site to see if a firmware update is available. If so, apply it (preferably before installing Panther) – even if the manufacturer does not mention whether the update addresses this issue.

  • If you are not installing Panther on the FireWire drive itself, disconnect the drive from your computer until after you have installed Panther and updated it to version 10.3.2 or later.

  • Avoid chaining FireWire devices together, especially if a chained device lacks its own power supply. If you have more FireWire 400 devices than your computer has ports, use a powered hub – or better yet, if you have a PowerBook or Power Mac, add a second FireWire bus using a PCI or PCMCIA card.

If you must use a FireWire 400 drive but cannot back it up or avoid chaining devices together, consider these additional precautions:

  • Be sure the drive’s FireWire cable is unplugged when you turn on your computer.

  • Before shutting down, restarting, or putting your computer to sleep, unmount any volumes from the FireWire drive and unplug the drive’s FireWire cable.

  • If your computer is set to sleep automatically, temporarily disable this feature in the Energy Saver pane of System Preferences.

  • Plug in the drive only when Panther is running. Again, be sure to unmount the disk and disconnect the FireWire cable when you finish using the drive.

What If My Hard Drive Is Already Fried? Conventional disk repair applications such as Disk Utility, Norton Utilities, TechTool Pro, and even DiskWarrior cannot repair drives that have encountered this problem or recover data from them. Quite a few users have reported success using Prosoft Engineering’s Data Rescue X, however. If even that fails, you may need to send your drive to a data recovery service such as the highly regarded (but not inexpensive) DriveSavers.

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"Take Control of Upgrading to Panther" — Advice for users of FireWire 400 hard drives is just one of the topics I expanded greatly in the latest edition of "Take Control of Upgrading to Panther." Now at version 1.2, this 89-page ebook covers all the steps you need to follow for a worry-free upgrade to Panther from any earlier version of the Mac OS. Most of the new content comes in direct response to inquiries I received from readers. Even if you’ve already upgraded your computer to run Panther, you will find extensive troubleshooting tips, suggestions for storing frequently used files somewhere other than your startup volume, and information to help you understand and cope with some of Panther’s most surprising changes. I hope you find the book helpful!

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[Editor’s note: As is our policy, anyone who purchased an earlier version of Joe’s ebook may receive this update for free. To that end, we notified all purchasers of the new version last week via email (and nearly half of our readers have downloaded the update already!). However, a number of messages bounced due to changed email addresses and spam filters, so if you didn’t receive notification, please use the form at the bottom of our Ordering Tips page to ask me for help. Also note that we’ve started a referral program for readers; click the button on the cover page of this update to Joe’s ebook to send a 10 percent discount coupon to a friend and receive 10 percent off your next order as well. Thanks for helping to spread the word about Take Control! -Tonya]

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[Joe Kissell is a writer, consultant, and Mac developer living in San Francisco.]

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