> From: tech-boun...@lists.lopsa.org [mailto:tech-boun...@lists.lopsa.org] > On Behalf Of Luke S. Crawford > > It used > to be they would sell products that took normal DIMMS, battery back them, > and would output a normal sata connector. The last time I saw such a > device it only supported non-ecc ddr2, and thus was completely useless > to me.
Bear in mind, the magnetic surface of a disk platter doesn't do ECC either. But in response to this, they use FEC chips on the circuit board of the hard drive, and encode more bits onto the magnetic surface. Whenever a checksum error occurs, the disk controller will silently retry (indicates a soft error, a 1-rotation performance hit) but as long as there's no error on the 2nd or 3rd or 4th attempt, the hardware silently hides this condition from the OS. You might get SMART indicating failure predicted. So what if your device only takes non-ECC ram? Does it have a FEC chip on the controller board? Does your OS/FS do any checksumming? Have any redundant copies with which to restore/recreate data after a checksum error occurs? There are so many levels of checksumming and error detection/correction. I agree zero isn't enough, but ... Is it really zero in the case mentioned? _______________________________________________ Tech mailing list Tech@lists.lopsa.org https://lists.lopsa.org/cgi-bin/mailman/listinfo/tech This list provided by the League of Professional System Administrators http://lopsa.org/
