michel@etlcom.etl.JUNET (Michel Pasquier) (04/25/89)
It seems that recently we had a lot of various discussions about the usage and reliability of magnetic storage devices, the result of which could be summarized as (one line per topic - majority opinion only) : 1- unused (backup) floppy disks should *not* be trusted for long 2- hard disks had better *not* be switched on and off everytime 3- floppies could suffer from (airport) Xrays exposure, but *not* hard disks Concerning the 2nd point, I would really be curious to know what evaluation could be made of a disk warm up / shut down in term of MTBF - which after all is the official measure for a HD lifetime (comments?)... But my main point is with the first topic: what about tapes and hard drives? How long can we trust our precious backup tapes or K7? (I would have believed the answer is "years", provided the stuff is stored in a normal place, but now I feel the urge to ask confirmation... all the more I *do* have a sun k7 I cannot read anymore - by the way, is there a remedy?) I also have some archival tapes I have not read for years (at least 2 or 3): is there something to fear? 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? Thanks for your comments and answers. -Michel. <<<< P like in paranoia ? No, P like in prudence >>>>>
russotto@wam.UMD.EDU (04/26/89)
In article <24679@etlcom.etl.JUNET> michel@etlcom.etl.JUNET (JoKeR) writes: > > It seems that recently we had a lot of various discussions about the usage >and reliability of magnetic storage devices, the result of which could be >summarized as (one line per topic - majority opinion only) : > > 1- unused (backup) floppy disks should *not* be trusted for long > > 2- hard disks had better *not* be switched on and off everytime > > 3- floppies could suffer from (airport) Xrays exposure, but *not* hard disks > > > But my main point is with the first topic: what about tapes and hard drives? > > How long can we trust our precious backup tapes or K7? (I would have believed >the answer is "years", provided the stuff is stored in a normal place, but now >I feel the urge to ask confirmation... all the more I *do* have a sun k7 I >cannot read anymore - by the way, is there a remedy?) I also have some archival >tapes I have not read for years (at least 2 or 3): is there something to fear? > > 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? > > Thanks for your comments and answers. > > > -Michel. <<<< P like in paranoia ? No, P like in prudence >>>>> The only backup problem I have EVER had is with 3.5 inch floppies. 5.25 inch floppies seem to keep indefinitely, and hard disks that haven't been used don't seem to be problem, provided you give them time for the temperature to adjust. -- DISCLAIMER: Not only does the University not share my opinions, they don't want me sharing my opinions. "This 'Pnews', what does it do?" Matthew T. Russotto russotto@wam.umd.edu
schmoldt@dcdwest1.UUCP (Daryl Schmoldt) (04/28/89)
In article <24679@etlcom.etl.JUNET> michel@etlcom.etl.JUNET (JoKeR) writes: > It seems that recently we had a lot of various discussions about the usage > and reliability of magnetic storage devices, the result of which could be > summarized as (one line per topic - majority opinion only) : > 2- hard disks had better *not* be switched on and off everytime I have been following the "to-turn-off or not-to-turn-off" discussion for awhile and I was wondering if there was anyone out there who has bothered to look at their opeartors manual to find out the manufacturer's recommendation is as to how long a specific hard drive should, or should not be left running. I have a Mac SE with an internal 20M HD and the operators manual (you know, the one that comes with the computer and that you don't bother to read until something explodes) says that as a general rule of thumb, if you are not going to use the machine for a period of about 8 hours then it is just as well to power down the system. As I said, that is the recommendation for my machine, your recommendation may vary. :-) Assuming that the manufacturer is not trying to lead you astray so that they can sell more disk drives by making you wear yours out via. unnecessary power cycling IMHO looking in the manual that came with your disk drive would probably be a safe bet. (Gosh that's a long sentence) The proverbial moral of the story, "When in doubt, RTFM." Daryl Daryl Schmoldt ITT Defense Communications San Diego, CA schmoldt@dcdwest.UCSD.EDU
folta@tove.umd.edu (Wayne Folta) (04/30/89)
[Stuff Deleted]
"I have a Mac SE with an internal 20M HD and the
"operators manual (you know, the one that comes with the computer and that you
"don't bother to read until something explodes) says that as a general
"rule of thumb, if you are not going to use the machine for a period of
"about 8 hours then it is just as well to power down the system. As I
"said, that is the recommendation for my machine, your recommendation
"may vary. :-)
"
"The proverbial moral of the story, "When in doubt, RTFM."
I think that most of us were aware of the Party Line on the issue (at
least I was). But remember that Apple has concerns other than maximizing
your SE or disk's life: liability. They could never recommend full-time
power on, as that would involve long periods unattended, and if a fire
resulted, someone in this sue-happy land would sue Apple to get a new house.
This scenario doesn't have to be very likely, it just has to be remotely
possible (like lawn mowers with warnings not to stick your hand into the
blade).
Note also that for practical purposes (in, say a business), "8 hours" means
"turn it off when you go home in the evening". Which leaves the question of
whether or not Apple means "8 hours" or whether that sounded nice. I, for one,
have worked with people who make manuals, and a firm number, like "8 hours",
might just be a reasonable-sounding number that someone inserted without
any research ("Hmmmm... let's see... it doesn't seem like it would be good
to turn it off for only an hour, but leaving it on all the time sounds risky,
so let's recommend, oh, say...8 hours!" :-)) I, for one, was looking for
some real real advice from EEs and MEs, so that I could weigh the tradeoffs and
make an intelligent decision.
Wayne Folta (folta@tove.umd.edu 128.8.128.42)ack@eleazar.dartmouth.edu (Andy J. Williams) (05/04/89)
[] I am using Redux to do my backups and have run into some strangeness. When I initially did the first backup, I had ALL FILES checked. Redux backed them all up. When it came time to do incrementals, Redux informed me that some of my files had changed. Well, I knew that the changes were insignificant, even useless (e.g., a file which had gotten nVIR and then had it removed *after* the initial backup) so I removed the check from these files. When I finally did need to do a restore, all of these files were gone. The question: When I meant to tell Redux "don't bother with the incremental on these files and just go with the originals" did Redux think I meant "ah, he wants to nuke these files from the backup set." If so, how can I get Redux to ignore files like those I mentioned above? Second question: What other backup programs are there which are comperable to Redux? Redux seems to always create larger and larger sets. When I had removed about 8 MB of junk from my HD and added ONE new large file (700K) the backupset GREW by one disk when (I thought) it should have shrunk by at least 6. Whose fault is that? Am I again not using it correctly? eMail replies, I'll post to the net if there is interest/news. -Thanks in advance -ajw Andy J. Williams '90 | <hello> | ack@dartvax.dartmouth.edu 31 North Main Street | set $NAME='inigo_montoya' | Systems Programmer Hanover NH, 03755 | You kill -9 my ppid | Kiewit Computation Center 603-643-2177 | prepare to vi | Dartmouth College