Message-Id: <mailto:199409101700.MAA19757@library.wustl.edu> Date: Sun, 11 Sep 1994 13:01:56 +0300 From: Jim Lindner <mailto:vidipax@PANIX.COM> Subject: Re: More digital resolution / Media life expectation To: Multiple recipients of list IMAGELIB <mailto:IMAGELIB@ARIZVM1.BITNET>
I am beginning to lose track of who wrote what here, but SOMEONE wrote:>I just dropped in on this, so please excuse if I'm commenting on
>something that's already been posted. Perhaps magnetic shouldn't
>be the standard to which non-digital archives should be compared
>since optical digital storage has significantly longer storage time so
>as to currently be seen as the preferred digital archive medium. I'm
>not an expert, so invite any who knows better to reply. I'd just prefer
>to not have the best option excluded from the discussion.
I am not convinced that optical digital storage does indeed have significantly longer storage time. Although for some reason the world has jumped to this conclusion, I have seen very little (ok, almost no) real research other than manufacturers "accellerated aging" tests which indicate that optical digital storage DOES last for long periods of time while providing data integrity.
Perhaps quoting from 3m's own Technical Bulletin Dated June 1993 entitled "Care and Handling of CD Recordable (CD-R) Disks" can provide some insight.
"Handle the disk only by the outer edge to prevent fingerprints and smears on the surface. Never touch the green recording surface or place it face down on a hard surface"
"Do not leave the disc in direct sunlight or in a hot, humid environment. These conditions may warp and damage the disk."
"Store the disk in the protective case. Proper storage helps protect the data from damage due to scratches on the disk surface."
"Store 3M CD-R media within this Termerature/ Humidity range: -5C to +30C, 5%RH to 60%RH (maximum wet bulb ò9C) Do not allow moisture to condense on the disc.
The article continues with cautions about:
Cleaning media and technique Solutions for cleaning Correct marking pens, and "never use a ballpoint or hard point writing utensil as it may damage the disc" Adhesive labels Disc labeling area etc.
Does this sound like the "the preferred digital archive medium" to you? I am not so sure. Ever see someone drop a record of any type? Ever see any media get scratched from years of removal and insertion into its "protective" container, or falling on the floor or from a desk? Ever see someone write on media by mistake (or out of ignorance) with a ball point pen? Ever see temperatures and humidity vary widely due to items being in transit, failure of HVAC, flood, and the dreaded family attic or basement? Sure you have.
I am not a CD-ROM or any type of any type of media basher, just a realist and the guy who has probably restored more videotape than anyone on the planet, so I have seen what can happen. I think that the prudent way to look at all of this is to realise that we live in a very exciting time, when storage media for all types of information is in very rapid transition. If one plans for and expects this type of transition, the "media migration" issues are not so overwhelming. There are those who have large commercial reasons for trying sell the expectation that one particular media form will last for "archival" periods. Beware of those selling perpetual life.
Jim Lindner VidiPax The Videotape Restoration Company Toll Free Help Line 1-800-653-8434