Disposing of old media

Discovering boxes of old backup tapes and hard drives when a
client finally got around to cleaning out their PC graveyard and a press
release pitching an NSA certified CD declassifier have me thinking about the
process of media disposal.  While I've
always found a little thermite to be effective I understand that violent
exothermic reactions aren't everyone's cup of tea.  So how should you dispose of old tapes and
disks?

In the old days you could just throw them in the dumpster.
Today that would put you on the wrong side of state laws that require embarrassing,
and expensive, disclosures when personally identifiable information like social
security numbers are lost or hacked. Hopefully the pitiful, if frequently
entertaining, stories of tapes full of medical records stolen along with the
courier's car have convinced you all to encrypt all your tapes.

Unless you're worried about the NSA or Mossad spending yottaflops
to decrypt your old tapes and figure out that you're selling antimissile
secrets to Hamas you can safely throw encrypted tapes in the dumpster. This of
course assumes you've avoided the stupidity of writing the encryption key on
the tape labels (Yes I've seen it).

Working ATA and SATA hard disks of recent (post 2001)
vintage have an embedded secure erase command that effectively locks drives
until the data overwrite completes even if the drive is powered off in the
middle of the process.  As a result you
can use the freeware secure erase program from UCSD's Center for Magnetic
Recording Research http://cmrr.ucsd.edu/people/Hughes/SecureErase.shtml
to clear drives in a couple of minutes .