On Fri, 12 Sep 2014 09:16:54 -0700, Anne & Lynn Wheeler wrote: > >re: >http://www.garlic.com/~lynn/2014k.html#7 [sqlite] presentation about ordering >and atomicity of filesystems > >part of the issue was that incomplete write ... with propogated zeros >... would also (then) rewrite the error correcting codes for the record >(with propogated zeros) ... so there wouldn't even be an error >indication that the write was performed incorrectly (installation >wouldn't even know to perform restore because of write error). > It's almost as if they concealed the error on purpose. Well, not quite; it depends on where in the data path the ECC was generated -- it should have been done farther upstream.
>later fba disks ... especially in conjunction with raid ... had >requirement that single block write would complete correctly once >started. ... > With what probability, and subject to what assumptions? If the data lead to the write head fails mechanically at a critical time, a bad block will be written. Negligibly improbable? Yes. Physically impossible? No. Detectable by ECC? Probably. -- gil ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
