Sometimes the problem isn't with the hardware but with a key system component. In that case, you may be able to boot with a Linux LiveCD, mount the drive, and copy off all your crucial files. This trick works whether your hard drive was running Linux or Windows, as long as the LiveCD understands the filesystem on the drive.
Of course, that assumes you have space to which you can copy the data. Sometimes it's handy to just mount your laptop hard drive on a desktop PC to copy the data quickly. Unfortunately, laptops and desktops use different IDE connectors. But heeeey, that's not a killer problem. Cables to Go makes a laptop-to-IDE hard drive adapter that lets you hook up the notebook drive to your desktop PC. I just ordered one this morning -- the cheapest I could find was at TechSunny.com.
I gotta admit, I'm not cool like the Fonz, but I know NewsForge readers are. Got any more tips like this you'd care to share?
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The problem you're trying to get around is head sticktion. The manifestation is that your disks don't spin up to speed fast enough, and the startup process times out. You can actually hear the disks trying to spin up repeatedly.
Removing the drive, rotating it back and forth quickly on the axis of rotation can free the heads. Best way to do this is to hold the disk flat in your hand, and rotate your wrist quickly. Sort of as if you were, um, polishing a knob.
The key to drive recovery is to try the least-damaging options first. Eg: restart, spin, freeze, mild shock (1"-2" drop onto a padded surface), etc. Some of these actions can actually damage the drives (head crash sucks), so start conservative.
I used the hand-spin method to revive a set of 6 year old drives on a system which had sat unused for nearly a year, following a move. Running fine to this day.
Pretty much any hard drive manufactured in the past seven years has S.M.A.R.T. capabilities -- that's self monitoring analysis and reporting technology. This won't help you revive a long-idle dead drive. It may give you advance warning of an impending drive failure.
You can access the SMART features under Linux with <tt>smartmontools</tt>. They key facts are these:
Most distros allow for installing the SMART monitoring tools. Check your logs for any test errors. You can plan your drive replacement while data are still accessible.
Details: <A HREF="http://www.linuxjournal.com/article/6983" title="linuxjournal.com">Monitoring Hard Disks with SMART</a linuxjournal.com>, <A HREF="http://smartmontools.sourceforge.net/" title="sourceforge.net">http://smartmontools.sourceforge.net/</a sourceforge.net>. The linked whitepapers at the latter give a good overview of the stats associated with the tests, though the long/short test info is most of what you need to know.
The authoritative answer will be in the whitepapers, linked at the Sourceforge site in my previous post.
The tests are AFAIU not based on any destructive tests to the drives. My understanding is that most of the tests are checking historical registers (the drives log errors / issues), and checking performance to see that it's within spec (spin up, head movement, etc). A long test is good for some interesting sound effects....
If you've got an already dodgy disk, there's probably a possibility the the tests themselves will result in failures, so your first step should probably be to ensure your backups are current and complete.
There is a performance impact, particularly for the long test, and default installations tend to run this in what should be off-hours (your own lousy sleeping habits are not a developer problem.
There's a <tt>WARNINGS.gz</tt> file in my Debian install, which desribes a parade of horribles that may happen. Essentially: you can hang your OS fi calls are made on poorly designed hardware.
My own experience includes a drive which was operating far slower than spec, by an order of 150 times. Running the long test was simply not feasible -- I think it ran well over 12 hours before I terminated it (typical is ~20-40 minutes). But I took that as a strong indication that the disk was, in fact, not 100% dependable.
Speaking of thumping
Posted by: Anonymous Coward on February 07, 2005 10:20 PM#