At 15:10 09/20/2005 -0700, Gus Wirth wrote: >At 13:46 09/20/2005 -0700, m ike wrote: >>On 9/20/05, Gus Wirth <[EMAIL PROTECTED]> wrote: >>> I've tried looking for this double-buffered ddd and haven't been able to >>> find it. >> >>google results for: double-buffered ddd >> >>http://www.ugu.com/sui/ugu/show?I=software.backup&F=1111111111&G=Y >> >>http://paxutils.progiciels-bpi.ca/showfile.html?name=courriel/perf-double-b >uffering&index=1 > >Thanks. Not sure why I couldn't come up with some code. Maybe I've been >hanging around Stremler too much ;)
Well, I downloaded the code and learned a couple of things. The first is that Knoppix is more cool than I could ever have imagined. To do my testing, I put two 60GB hard drives in my machine on separate IDE channels, one on /dev/hda the other on /dev/hdg which is a completely different controller. I made sure DMA was turned on and IRQ's were unmasked. I put the code on a floppy disk and then copied it into the knoppix user directory. I was able to do a compile in Knoppix! I had to edit the makefile for the code in the link above because it used spaces instead of tabs. It compiled into a working executable. I then did the following: time sudo ./ddd if=/dev/hda of=/dev/hdg bs=1024k It took 40 minutes to copy the 60GB drive, the same as regular dd without the double buffering. Data transfer rate is about 25MB/s. Looks like IDE drives are just slow no matter what you do. It was a fun experiment though. Gus -- [email protected] http://www.kernel-panic.org/cgi-bin/mailman/listinfo/kplug-list
