More use from the HDD than SONY ever planned.
neat
http://www.the-magicbox.com/0405/game053104e.shtml
HD Loader Publisher: Divineo
Platform: PlayStation 2
Genre: Utility
Origin: US
Release: TBA
"Divineo announced a new unofficial PlayStation 2 software called HD Loader, which allows you to install and run your PS2 CD and DVD games directly from a hard drive, effectively cut down the disc access time of games.
HD Loader is also compatible with both Sony's 40GB HDD and third party hard drives, you can choose a hard drive from 40GB to 120GB and install it in the hard drive bay behind the Network Adapter.
There are a few drawbacks to HD Loader, first it does not work with PSone games, second it is incompatible with DNAS (Dynamic Network Authentication System), therefore you cannot go online with a DNAS enabled game. So you still need to run all DNAS enabled game from the game discs.
A small number of games are not compatible with HD Loader, such as Resident Evil Outbreak, MX 2002, Peter Pan and Ratchet & Clank."