Russell Coker wrote:
On Tue, 1 Jul 2014 10:03:44 Rohan McLeod wrote:
> Noah O'Donoghue wrote:
>> Hi All,
>>
>> After reading about bitrot and feeling guilty for storing my most
>> valuable data on cheap drives (although with backups!) I've been
>> thinking about moving to something more resilient.
snip
informative;
but apart from a suggestion that it might be related to
'cosmic rays' and thermal magnetic effects;
couldn't seem to find
(a) a definition which is a measure of bitrot and
(b) actual measures of this phenomenon in various media and differing
conditions.
Presumably as a probabilistic phenomenon; bitrot might be defined in
terms of the half-life of the data ?
http://research.cs.wisc.edu/adsl/Publications/corruption-fast08.html
The above paper is the best reference I've seen. Half-life isn't a good
measure as you can expect to lose ~50 sectors at a time on a TB+ disk.
Thanks for
responding Russell
This paper doesn't seem to distinguish between corruption attributable
to drive 'malfunction' and
corruption which would have happened anyway ? eg while the drive was
switched off
But I notice :
"/(ii) checksum mismatches within the same disk are not independent
events and
they show high spatial and temporal locality,"/
Presumably bitrot due to temperature would not show " high spatial
locality " ?
https://en.wikipedia.org/wiki/Curie_temperature ;
so perhaps we can deduce cosmic rays a more likely cause, than
temperature ?
regards Rohan McLeod