Thanks!


It's got something to do with conflict as to whether error handling should be undertaken by the hard drive or by the RAID controller. WD had added a 7 second delay on RE disks so the RAID controller would have the time to pick up and act upon them. WD claims this is necessary, and sells these RE drives at a considerable price premium. The stupid part is that there is a small application floating around on the web which can also set this TLER switch on non RE disks, effectively making them RE disks at considerably lower cost. Of course WD also claims there are other difference to the RE series like use of better materials etc, but afaik that has never been proven. It is a fact though that, by taking this step, WD has made building a RAID array considerably more expensive for users - if they choose to actually by the real RE drives that is.
There is a wiki entry for this.