external hard drives
Normally I find a standard drive inside with a USB or firewire interface card attached, and the problem often lies with this interface card - removing the drive and popping it directly into a computer I can get on with recovering data and all's good.. Having standard drives inside external cases can be good too in that price specials come up that mean it can be cheaper to buy an external drive, pry it from its case and using it inside a PC or laptop to upgrade or add a drive to the computer for less cost than buying a bare drive.
However, once I pried open the case to reveal the actual hard drive I discovered the internal drive uses an integral usb interface and not a standard sata/pata interface. This is not cool - not at all. Apparently Samsung has also been doing this too so it looks like a future trend driven by cost savings at the point of manufacture.
The problem is that while the drive appears to be fine and makes all the right noises on startup, the computer doesn't see the drive at all - which suggests the usb interface has failed.
So as the only way to easily talk to it is through the now non functional USB and that option is gone, the next way will be by swapping the hard drives board - something that rarely had to be done with conventional drives and means sacrificing a new drive at least once to recover the data on the old drive - or by butching the drive board to try to pull the serial data off from some point.. which will not be easy - and even then the data is likely to be encrypted (according to http://www.pcworld.com/businesscenter/article/215681/selfencrypted_drives_set_to_become_standard_fare.html )
Here's some pics I found of what this interface looks like: http://i52.tinypic.com/ifsi9e.jpg http://www.hdd-donor.com/pics/1290113551.jpgAnyway this is just a warning that some newer external drives, while conveniently small and cheap (cough.. that's the new benchmark for everything these days, right?) may be a bit of a time bomb regarding preservation of data.
My advice is research any drives before you buy and find out whether they contain conventional style drives, and avoid these new ones like the plague