View Full Version : Slow Copying and I/O errors

02-26-2007, 09:49 PM
I had been used to using SuperDuper on an iMac G3, but having inherited a G4 iMac from a son and with daughter moving 4000 km away, I now had the capability to use iChat, so I started using an iSight to chat with her. About a month after starting to use the G4 iMac, I decided I should back up this computer. Well, rather than the 6 MB/sec copy speeds seen with the G3 iMac using SuperDuper, I was only seeing 0.6 Mb/sec, with the transfer process crashing after some hours. The SuperDuper log showed an I/O error after just about every file copy. I did review the SuperDuper manual and noted mention of failing disks being the cause of I/O errors. Since the backup disk was not the same as the one used on the G3 (the G4 had been upgraded to 320 GB, so I needed a new backup disk for it), I thought it may have been the cause. This 'new' disk had been used for storage before and it had been working OK. Attempting various types of 'erase' of the disk to identify bad blocks didn't improve SuperDuper's performance. Then I read further down the trouble shooting section in SuperDuper's manual, to discover that fire-wire iSights are problematic for SuperDuper. I hadn't noticed slow downs in Finder copying to the disk, prior to using it as a clone of the iMac, with the iSight attached, to have a clue that it might be the cause. Anyway, detached the firewire iSight and the intial clone, using SuperDuper, ran at 20 MB/sec, completed and was able to boot the G4 off it OK, phew!. While its old news for these forums, its likely us older folks will still be caught by firewire iSight problems as their children migrate to the intel macs and USB iSights, so I thought it worth reposting the issue in 2007.

02-26-2007, 09:53 PM
Yep -- definitely a problem on some Macs -- it's mentioned in the Troubleshooting section, too! :)