Date: Tue, 17 Mar 1998 15:19:22 -0800 (PST) From: William Maddox <maddox@p-1.Eng.Sun.COM> To: freebsd-hardware@FreeBSD.ORG Subject: Re: CD-R and Scanner recomendations for CD archiving of records? Message-ID: <Pine.GSO.3.96.980317144022.23331B-100000@p-1> In-Reply-To: <Pine.BSF.3.95.980317162415.10950H-100000@orion.webspan.net>
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On Tue, 17 Mar 1998, Open Systems Networking wrote: > Rob, > > What you say above is probably true. But I think you have just backed up > my 2nd post about using a more reliable media than CD-R like punchcards. > I mean look at all the work involved in your steps above to do archiving. > reliably :) > It would be MUCH easier, and more reliable for me anyway to just grab a > SCSI DAT drive and archive away. I dont mean to tear down your obvious > love of CD-R, but your guidelines are like that of windows. You can run > windows reliably! Just only run it on tuesdays, BUT you have to have a > black cat ON the monitor, AND it has to be past sunset!! And some holy > water never hurts :) > > I still say after my CD-R problems it's a better choice to just use a SCSI > DAT tape drive. More storage, and will last far longer in my opinion than > CD-R which is aparently quite finicky for more people than just myself. Magnetic tape is *not* a satisfactory archival medium. Although I cannot report from personal experience, I believe that there is a consensus amongst storage professionals that CDR is a more stable medium than tape. In any case, I've seen enough horror stories on this mailing list in the past to convince me that tape is not a reliable archival medium. Leave a DDS or QIC tape on the shelf for a few years, and you will likely not be able to read it. CDR is not nearly as difficult as Rob makes it sound. Use a decent SCSI setup, always write from an image file with no other processes running, and use high-quality media. You don't need a 7200 RPM drive. Some older CDROM drives have problems reading CDR. This is understandable -- the optical properties of CDR are different than silver CDs, and drives designed before CDR was in widespread use were likely not designed for or tested for compatibility. Buy a new one. (My guess is that the automatic gain control used in a so-called "multi-read" CDROM drives to handle CD-RW media should also benefit CDR, which is somewhat less reflective than silver CDs, though not as much so as CD-RW. Anyone know for sure?) The objection raised earlier against CDR is that they are difficult to write successfully, or that they are easily damaged. Event granted that this is true, the most important question is "How stable is a successfully written, verified, and properly stored CDR over time?" I've seen archival lifespans quoted from between 30 and 100 years. What other medium would you suggest for 5 to 25 year storage? Another advantage of CDR worth considering is the popularity of the readers. It greatly increases your chances of maintaining your retrieval capability as your hardware ages and becomes obsolete. All of this aside, I question the wisdom of using *any* machine-readable medium for long-term archival documents such as court records. Archival paper properly cared for can last for centuries, while it is almost guaranteed that 20 or 30 years from now, any currently available technology will be so hopelessly obsolete that new readers will not be available. Even if you can scrounge up another antique to replace your own aging and broken reader, you might not be able to transfer the data to a more up-to-date medium. An example: I have two 9-track tapes from my student days at CMU, both about 15 years old. It would be a major effort for me now to track down a 9-track tape drive that I could use to transfer the data to a medium that I could use on a modern PC or workstation. It would not be worth buying such a drive, and most shops without legacy hardware or the need to interoperate with same would own one. --Bill To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hardware" in the body of the message
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