Re: [AV Media Matters] Digitizing Audio and Video

[johnsp@comcast.net]

Jim,

Thank you for the information below.  I have heard in the past that
rewinding was NOT a good thing to do on a regular basis.

I guess I probably misused the term "cycling", as I was more curious if
there were any schools of thought regarding how often data tapes should
be
"cycled" to another tape.

Let me describe an example.  If you put data on a tape (LTO, AIT, DLT)
and
then it is stored in a proper vault (meaning it is not connected to a
near-line or online storage device), assuming that you have geographical
separation, when should the data on those tapes be moved to another set
of
tapes?  Is there empirical information beyond the manufacturer's claims?

Thanks in advance,
John Spencer

> From: Jim Wheeler <Jimwheeler@aol.com>
> Reply-To: AV-Media-Matters@topica.com
> Date: Thu, 29 May 2003 22:15:28 -0400 (EDT)
> To: AV Media Matters <AV-Media-Matters@topica.com>
> Subject: Re: [AV Media Matters] Digitizing Audio and Video
> 
> John
> 
> By "cycling" I assume that you mean rewinding the tape every few
years.
> 
> That originated in a 1958 report by GKI.  It does not apply to
> backcoated 
> tapes, which were introduced in the late 1960s.
> 
> In 1978-79, Ampex was contracted by the U.S. Air Force to update the
GKI
> 
> report.  In 1981, I was asked by SMPTE to summarize the data from the
> U.S. Air 
> Force report.  This resulted in the article that I wrote for the SMPTE
> Journal.  
> It was in the June 1983 Journal and was titled "Long-Term Storage of
> Videotape".  That article catapulted me into the limelight of the
world
> moving image 
> archival community.
> 
> In the SMPTE article, I quoted the Ampex study that said that tapes
> stored at 
> 70 F should be rewound about every two years.  At least this was
better
> than 
> the six month figure from the GKI report.
> 
> Since I wrote the SMPTE article, I have given a lot of thought to tape
> rewind 
> intervals.  The obvious question is "why rewind?"  The reason is to
> minimize 
> distortions in the tape pack.  The next question is "Why do tape pack
> distortions occur?"  The answer is because of changes in pack
> temperature during
> storage and because of incorrect tape wind tensions just before
storage.
> 
> If a tape is wound at 65-70 F, at the correct tension, and stored
around
> 65 
> F, then tape pack distortion should not occur and rewinding is NOT
> necessary.  
> Even if you do find a tape with pack distortion, the tape can be
> returned to 
> normal by a couple of high-speed winds.
> 
> In summary, wind the tape before storage and store the tape at a
> consistent 
> temperature.
> 
> Several of us on this Listserve agree that winding tapes every few
years
> is 
> more likely to damage the tapes.  Let them set on the shelf and age
> naturally--or is that organically?
> 
> BEST
> 
> Jim Wheeler
> 
> 
> 
> 

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