On Sun 10 Jan 2010 10:15:10 NZDT +1300, Bill Davidsen wrote: > There was another error having to do with reading data at the end of an > image. Due to read ahead settings a read past end of data occurred and the > (valid) partial data was not returned to the user program. Might that be > what you are remembering?
Thanks for mentioning it. Since the mid-90s the kernel produces I/O errors reading the last blocks of an ISO image from actual disk because of a read-ahead function. Turning off read-ahead is not sufficient to prevent this error, turning off DMA is also necessary (presumably that has its own read-ahead too). This problem because suddenly worse again a few years ago when DVDs arrived (larger block size, larger read-ahead). I can't say whether it's ever been fixed completely, I always use a workaround for my own disks, but haven't seen it much on other disks any more. Volker -- Volker Kuhlmann is list0570 with the domain in header http://volker.dnsalias.net/ Please do not CC list postings to me. -- To UNSUBSCRIBE, email to [email protected] with a subject of "unsubscribe". Trouble? Contact [email protected]
