Dear All, Thank you for your replies to my question. Here is a summary: The question was, how to copy an entire hard disk to another hard disk in a usb box most conveniently.. the command is: dd if=/dev/sda of=/dev/sdb bs=X (X=blocksize). - Herbert recommended a blocksize of 1 Mb (bs=1M) - Per is using blocksize of 65536 bytes ~ 65 Mb - Dave warned that blocksize*block should fit in real memory (or is it just "blocksize" maybe?). I have "436593072 blocks" in my /dev/sda3 partition (according to df). So with the minimum blocksize of "512" and talking in gigabytes, i.e. (436593072*512)/1000000 ~ 223535.. so I should have "223535" Gb of memory..? Something weird here. - There is a general consensus that eSATA should be more efficient. - Greg says that 512 (i.e. the default) blocksize works "surprisingly well" with raw disks (i.e. with /dev/whatever), but for real files 4Kbytes should be used and in the case of tape drives, larger blocksizes are necessary. (.. some contradictions here with the optimal blocksize). - Carlos said implicitly that USB might be the bottleneck.. and yes, it is a real hard disk and I have a mouse connected to my computer via usb as well. According to Carlos'es experience, eSATA is much more "rapido". .. btw, I have tried to copy my 500Gb hard disk only during ~ 12 hrs (error in the original e-mail) with the default 512 byte blocksize, i.e. during the night. In the morning it was still copying.. :( Well.. I guess I'll try tonight again with the 65 Mb blocksize and if that is unacceptable (more than one night) I'll be off to by an eSATA thingie for my laptop. I am very familiar with rsync and I am using it all the time, but I just want an identical copy of my hard drive every now and then.. just in case. Regards, Sampsa -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org