I have a magnet plate hanging over my desk. Usually, the normal magnets for that purpose you can buy in shops are of very low quality and not very strong and fail to hold more than a few pieces of paper.

I recently discovered a way to get much better magnets almost for free: From old harddisks. To open a harddisks, you will usually need some kind of Torx screwdriver. Inside, you will find one or two very strong neodym magnets, which were originally used to move the read head.

A common way to check the health state of a hard disk is SMART. It gives various informations about occuring errors. In Linux, there's the smartmontools package containing tools to read SMART data of hard drives (smartctl -a /dev/[hddevice] gives you a bunch of information).

I found it always frustrating that SMART didn't work with USB drives. It's a standard bound to IDE/ATA. Although common USB-drives are internally IDE/SATA, sending the SMART commands to the drive requires proprietary extensions. But now, the smartmontools-developers have included support for some USB drives. It worked with the USB HDs I had available for testing.

There's no release yet containing the USB-support. If you're on Gentoo, you can fetch a live-CVS ebuild here.