[comp.sys.mac] Re^2: Have you checked your backups lately?

paul@torch.UUCP (Paul Andrews) (05/08/89)

michel@etlcom.etl.JUNET (Michel Pasquier) writes:


> Also, what about a hard drive which remains off power in its box for months,
>a full year or even more?  Is is *absolutely* safe or is there some risk of
>data loss? 

Well. The tests that manufacturers of hard disks impose on their media are
quite subtle. For example, it is possible to format a hard disk and verify
it free of errors even though there are bad sectors listed on the defect
list that came with the drive. However, you SHOULD map out the sectors that
appear on the list. If you do this you shouldn't have any problems until the
drive collapses in a big heap from over use, this should take between
2 to 4 years (statistics being what it is). HOWEVER, if you get a head
crash, you might as well use it as a paper weight (drinks mats are another
option). You may well be able to re-format it and map out the apparently
bad tracks (I've even known some disks improve the more they were
reformated), but it'll go wrong again real soon, either because of stray
lumps of magnetic media floating about or because some of the areas that
formated OK will gradually float to a random state.

P.S. head crashes are pretty rare these days.

- Paul.