magic growisofs

[Wojciech Puchar]

i have DVD-sized partition with data.

when i do

growisofs -dvd-compat -speed=1 -Z /dev/cd0=/dev/partition

EVERY DVD gets broken. i get read error somewhere (most often - between 
2-3GB) when checking it with

dd if=/dev/cd0 of=/dev/null bs=256k


BUT - if i copy that whole partition image to file (on other,large 
partition) and record from file - EVERY DVD is OK.

recorder and hard drive are on different ATA busses.

any idea?