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Tuesday, July 24, 2012

The Hard Drive Resurrection!

My first hard drive 'incident' occurred years ago when a friend moved a hard drive of mine while it was still working. The result was 'smoky' and resulted in a drive that would not spin up and a fried controller board. Switching boards for data recovery was simple though as the drive was of desktop size and the model fairly common. 

Since then I've sufferred all sorts of drive failures from virtually all drive manufacturers. While I haven't lost much data (I backup regularly) it has been annoying and I've learnt about hard drive technology along the way. Last year I had another drive failure. This time it was a laptop sized drive with a supposedly 'seized spindle'. I tried 'freezing it' in a sealed container and it seemed to spin up long enough for me to recover the data but after one power up that was basically all the activity that I ever saw again from this particular drive. Since I recovered the data I didn't bother with further experimentation. Recently though, some other work in data recovery brought this drive back into my mind. I opened up the drive and was reminded that even though hard drive technology has been around for decades it has definitely evolved/become more refined. Drive designs from a decade ago there were much more distinctive between drive manufacturers than now and there were sometimes aspects of drive design which could have easily been improved (such as shock absorption and chip placement). Over time, its become clearer that drives have become much more refined though and manufacturers have converged upon some similar design principles. When I opened this particular drive it was obvious how much thought was put into it; there were stickers to prevent improper screw placement (some screws could have protruded directly onto the underside of the drive platter if you weren't careful), contingencies were made to deal with the possible build up of internal condensation/contamination (packet of what appeared to be silica/cotton?), and even minor design changes to head parking areas to reduce the shock of drive movement to the extreme edges of the disc platter themselves.

Anyhow, it seems clear that there are several methods when dealing with seized spindles. One involves using a power drill, another blunt force, another involves a specialised tool to help re-align the platter/bearing bundle. I decided to use a stylus from my old Palm Vx. It seemed to work well and I was at least able to get my drive spinning relatively freely again. The next problem that I faced was head/servo movement. I checked my re-assembly several times and everything seemed to be in check. However, after careful examination I realised that a cable that led from the controller board to the head was deformed/broken which meant that power could not be sent to an electromagnet at the end of the head assembly which is ultimately used to control head alignment over the disc platters. After re-alignment head movement seemed to be back. While its clear what the problem is, I'm not sure how much further I can push this with my existing equipment. The connections/wires that need to be fixed are basically the size of pin heads. It will take a microscope and a bit of luck to be able to accurately re-connect the relevant connections.

Moreover, unlike previously where switching parts seemed to be quite simple I'm discovering that drive recovery nowadays is far more evolved than it used to be. While some parts are interchageable others aren't so easy. Based on some research it seems as though some drives may have begun to place part or all of the firmware on the actual drive itself which makes parts transfer not so simple. The firmware from the old drive needs to be extracted or procured from another location (can be trivial or extremely difficult depending on the situation/manufacturer as some publish tools/software to do precisely this while others rarely publish any supporting documentation/software at all).

I suspect the best/simplest method may be sourcing another drive for its head assembly (if you don't have specialised head removal tools you're best choice is turning the drive upside down and pushing it towards the back wall of the drive enclosure to remove it and enhance your chances of removing it without causing significant drive damage)(Obviously, you've discovered by now that you can often get by without having to resort to specialised tools a lot of the time. However, like general 'tradesman' it is far easier if you have them and you need to take extra care if you don't have them.). I'd like to know whether they alter drive heads based on drive density though? Clearly, when switching from single to multi-platter configurations this will be the case. How about switching from a single platter discs of different density though? Surely, efficiencies in mass production should mean that you use the same heads while altering only the platters, firmware, controller card, etc?

As an aside I've noticed a lot of good deals for SSDs of late. However, it's also clear that some of the drives on offer have a history of data loss as a result of dodgy controllers, firmware, etc... For the moment, I would do my homework before purchasing an SSD, hold off on the technology while it matures, and/or just use it for non-critical/read only purposes.

A word of note, if you're working with this type of equipment you should primarily be thinking about the most minimal way to get things going again rather than seeking the most elegant solution out there (at least initially). I recall working an phone that had sufferred from water damage. Everything seemed to be fine but the power switch needed to be replaced. While I managed to find a replacement from Jaycar I tried to get too cute with the repair and ended up damaging the replacement switch. Luckily, the switch was only 95 cents and the phone was relatively inexpensive.

http://en.wikipedia.org/wiki/Hard_disk_drive

http://www.overclockers.com/do-it-yourself-hard-disk-repair/
http://superuser.com/questions/44318/how-do-i-remove-a-mybooks-wd-smartware-virtual-cd-from-my-desktop
http://club.myce.com/f138/access-hard-drives-firmware-257428/#.UAoich-eVG0

Bible Codes, Random Stuff, and More

On Bible Codes: Obviously, I am somewhat curious about the origin of religion... Recently, I came across a book called 'Bible Code...