Re: [ARSCLIST] Preservation media WAS: Cataloguing still :-)

[Jerome Hartke <jhartke@xxxxxxxxxxxx>]

> -----Original Message-----
> From: Association for Recorded Sound Discussion List
> [mailto:ARSCLIST@xxxxxxx] On Behalf Of Bob Olhsson
> Sent: Sunday, September 03, 2006 9:46 AM
> To: ARSCLIST@xxxxxxxxxxxxxxxx
> Subject: Re: [ARSCLIST] Preservation media WAS: Cataloguing still :-)
> 
> Jerome Hartke wrote:
> >The problem is that all of these require head-media contact when reading
> >(playing) content.
> 
> Contact isn't required. There is no head contact in any rotating head
> device and early video tape designs even used compressed air to keep the
> tape away from the guides. In the case of hard drives, there is also no
> contact.
>  <snip>
> --
> Bob Olhsson Audio Mastery, Nashville TN
> Mastering, Audio for Picture, Mix Evaluation and Quality Control
> Over 40 years making people sound better than they ever imagined!
> 615.385.8051    http://www.hyperback.com


Unfortunately this is not correct. For several years, I professionally
tested both 4 mm and 8 mm helical scan tapes. The following observations
from that work are relevant.

1. The head(s) are mounted on a rapidly rotating drum, and do contact the
tape. They actually penetrate the transport plane causing local deformation
of the tape and abrasive wear.

2. Longevity testing involving 10-100 repeated passes over the same section
of the tape result in pileup at the end of the test section of material
abrasively removed from the tape.

3. Head clogs are prevalent wherein material abrasively removed from the
tape lodge in the head gap, and sometimes require replacement of the head or
the entire drive.

VHS technology is similar and would probably have issues similar to those
listed above.

Jerry
Media Sciences, Inc.