I have a Knoppix 4.0 DVD that came bundled with a computer magazine. The DVD seems to run fine. Nevertheless I wanted to check data integrity by entering "testcd" at boot. The computer began checking files, but after a while the DVD drive was spinning down and the screen turned dark. When I pressed a key, the screen came back, and I could see that the computer was testing the KNOPPIX2 file when it got stuck. I tried testcd with two different computers and never got beyond the KNOPPIX2 file.

Can anybody confirm this issue? Is "testcd" supported by the DVD versions of Knoppix?