jacobo@megatest.UUCP (02/18/87)
The question is: Is it safe to reuse mag tapes for important data or
should we use brand new tapes when storing critical information?
Would someone have a strong feeling, based on experience or data, one way
or the other? I know that the whole idea of using mag tapes is that you
can reuse them a good number of times, but I have also heard people
saying that valuable info should go on virgin tapes.
Any comments would be greatly appreciated. Please mail to me directly.
Thanks.
Jacobo
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PHONE: (408)437-9700 x 3171ems@apple.UUCP (02/22/87)
In article <1058@megatest.UUCP> jacobo@megatest.UUCP (Jacobo Bulaevsky) writes: > > The question is: Is it safe to reuse mag tapes for important data or > should we use brand new tapes when storing critical information? > > Would someone have a strong feeling, based on experience or data, one way > or the other? I know that the whole idea of using mag tapes is that you > can reuse them a good number of times, but I have also heard people > saying that valuable info should go on virgin tapes. > > Any comments would be greatly appreciated. Please mail to me directly. > Thanks. > I think this topic is of general enough concern that replies should be posted. I'm interested. WAR STORY: Once upon a time a company I worked for used virgin tapes for the important stuff. Then we started having a strange problem. Some tapes would be fine for a while, then after being stored for a few days would be unreadable. This was never completely solved, but was believed to be due to a batch of questionable tapes. MORAL: Use relatively new, but not virgin tape for really important things. You want to get past any 'infant mortality' problems and use a proven product. Avoid heavily used tape, as it can begin to develop problems. We did one of our daily backups on a virgin tape, then took the oldest tapes out to be 'keepers' This gave the tape a few uses before something critical went on it. If we hit a bogus virgin tape, it was only one days worth that was lost, the prior day having been done on a veteran tape. Of course, we had to check the backups periodically ... It takes a LOT of uses to wear a tape out. I would guess somewhere in the hundred range or so... -- E. Michael Smith ...!sun!apple!ems 'If you can dream it, you can do it' Walt Disney This is the obligatory disclaimer of everything. (Including but not limited to: typos, spelling, diction, logic, and nuclear war)
jnp@calmasd.UUCP (02/26/87)
> jacobo@megatest.UUCP (Jacobo Bulaevsky) writes: > The question is: Is it safe to reuse mag tapes for important data or > should we use brand new tapes when storing critical information? In the broadcast field (yes - I know that the recording techniques are different - but the media isn't) it is generally accepted that used but not worn-out tapes are best for archival storage. Has something to do with the original-factory-fresh erasing done, and that it takes several recording erasing cycles to make the tape really "take" a recording well. I have heard this arguement applied to Video tapes as well. My guess is that - at least to some extent - it would be true for digital tapes as well. -- These opinions are solely mine and in no way reflect those of my employer. John M. Pantone @ GE/Calma R&D, Data Management Group, San Diego ...{ucbvax|decvax}!sdcsvax!calmasd!jnp jnp@calmasd.GE.COM
tooch@guppy.UUCP (03/10/87)
>> The question is: Is it safe to reuse mag tapes for important data... > ...it is generally accepted that used but not >worn-out tapes are best for archival storage. Has something to do with the >original-factory-fresh erasing done, and that it takes several recording >erasing cycles to make the tape really "take" a recording well. Nonsense. Every single pass degrades tape through friction and tension (shuttle on a poorly designed transport is hell on tape). For that matter, the heads get worn and/or clogged also. Oxide comes off, the substrate stretches, etc. Each pass brings the tape closer to death, and statistically increases chances for droupout (the bugaboo of digital tape) and so forth. In the world of magnetic recording, unlike life, the first time is not only the best, it's also completely forgettable. With that said, I must also point out that the degradation experienced each pass varies depending on tape and transport, but by and large the first (say) dozen passes on a GOOD recorder SHOULD produce unnoticeable changes in the quality of a GOOD tape. This is as I heard it at Ampex. 3M might tell you differently. --Mike Tuciarone tooch@sun