Not sure if SF is exactly the place, but I was hoping this group would have solid experience. I am your run-of-the-mill desktop technician, and it hit me today I know very little about disk/data recovery beyond software-based tools. I am interested in dealing with failed hardware. If I was willing to change my career path a little, how would I get into the business of disk recovery? I know next to nothing about it. Does anyone have good books on the topic they recommend for personal consumption?
If you want to get into it, perhaps check for job openings at data recovery shops? My understanding is that it takes quite a lot of specialized equipment and supplies, for example the only time I've used it, they used a DDS tape drive with special firmware that allowed skipping past what the drive thought was the end of tape. Often getting data off dead drives involves replacing controller boards, or swapping the platters into a working head assembly in a clean room.
However, I'm sure quite a lot of data is lost not through hardware problems, but things like people accidentally removing files, which could be solved entirely by software...
Recovering from hardware problems -- especially RAID/hard drive related ones -- can simply mean "restore from backup". At least I won't trust the data that was stored on a failed hard drive. Most of the files might be OK, some of them could be left only partially, some of them might be listed on the directory listings but contain zero bytes. Of course, comparing MD5/SHA sums to known good ones helps, but that can also require comparing stuff to backups, unless you have everything stored in a Tripwire database etc. :-)
Many hardware related problems also do require some special equipment.
But, as Sean said, quite a lot of data gets lost due to software/user errors. For those you can again practise your backup restoration skills :-), and you can also install couple of virtual machines, and learn how to recover files accidentally deleted on Windows / Linux (and its many file systems...) / *BSD.
Having the know-how how to recover from software failures is essential before you can climb to even more advanced level (that special equipment, staring at the hex editor and so on...)