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Hi all, Belated thanks to all of you who responded to my question in November about digital image storage. In the best case scenario, most respondents seemed to favor keeping images on a server or removable hard drive and migrating file formats en masse as necessary rather than keeping the files on separate fixed media such as disks. But there are nuances, as you’ll see.
The rest of this email is pretty long--I’ve combined some of the answers I got along with answers to a related question on the ImageLib list from Anthony Troncale, AMNH Library, re DVD manufacturers; and added them below in response to Matt Morgan’s suggestion.
Best wishes for 2004,
Marla Misunas Collections Information Manager Collections Information and Access San Francisco Museum of Modern Art (415) 357- 4186 (voice) (415) 947-1186 (fax) ___________________________________ Board Member, Museum Computer Network Conference Co-Chair, Minneapolis 2004 www.mcn.edu
About archival storage media:
From Matt Morgan, Manager of Information Systems, Brooklyn Museum of Art
I’m coming at this from an IT perspective, rather than an archivist’s perspective, or that of a Collections Specialist. I would hate to think that you’re setting up a library of removable media, just because you’re running out of space on the servers. In an honest comparison, it would be probably cheaper to install a new server with some digital repository software (DSpace, for example, but there are some others) and tons of disk space than to set up a library of removable media and the related systems and equipment and people the library would require.
Whenever I think about this issue, hard disks seem like the best way to keep images, and not removing them from the server at all seems like the absolute best. In other words, I hope we can never have to remove out stored images from the servers. For these reasons: *Server disk space (while more expensive than cheap removable drives) is pretty cheap and continuing to get cheaper all the time. *You can easily back up your image DB occasionally, and send the tapes somewhere safe. *It takes effort not to lose track of a DVD or other removable media, if you’re really using it, but you won’t lose track of the server. *Distribution is simpler—people can get images out of the db, instead of calling the DVD librarian. *It probably takes less space, and fewer people (you don’t need a DVD librarian). *When you do have to migrate to new media, on-line disks are very fast and labor unintensive, relative to removable media.
…when the servers are filling up, and you have to change what you do, it’s probably a good time to look at the whole IT picture and see what your IT department could be doing differently, Personally, given the fact that disk space is so cheap, I feel like it’s my job as IT manager to make sure that BMA never runs out of it (while enforcing reasonable quotas and policies to make sure it’s not wasted). Managing server space is definitely not free or simple, and removable media is a valid option at times, but maybe there is a better way to handle your server space than the way it’s being done now.
From Hannah Frost, Media Preservation Librarian, Stanford University Libraries
At Stanford Libraries, we are migrating images from CD to server; the discs are about 4 years old. The only problem I’ve seen is one lost file which was probably recorded improperly in the first place (Lesson: conduct a lot of quality control while recording). I think there are lots of places that are actively refreshing their media on a regular schedule. The key to making this work is to designate a specific person for the job, figure out a way of scheduling the work in a timely, but realistic manner, use the best media you can buy from different batches and/or manufacturers, make multiple copies and store them in separate geographic locations, and be sure to keep equipment around in working order that can run the particular format you chose for your archival copies. This is not a prescription for success, but these are some of the most basic elements of a data presentation program. [Hannah recommends the following article, “Care and Handling of CDs and DVDs: A Guide for Librarians and Archivists” by Fred Byers, http://www.clir.org/pubs/reports/pub121/pub121.pdf]
From Tim Au Yeung, Object Repository Technologies, Information Resources, Univ of Calgary
In an ideal world, you’d have a NAS/SAN-based system for an on-line copy of a master file that is regularly checked for integrity with a CD/DVD copy offline in a separate location that is periodically spot-checked and replaced every 4-5 years from the NAS/SAN-based copy. Obviously, it requires a fairly large organization to organize a system like that and given the costs, two copies on optical media may be the practical choice.
What I would see as a practice that would lead to greater loss is to choose less than optimal technical standards for the digital files (resolution, bit-depth, lossy compression, etc) to try to conform to the existing storage infrastructure. Better to get all the quality you can in the files and settle for a more cost effective solution for storing them even if there is uncertainty at this point.
Notes from conversation with John Stalder, Digital Archive Manager at LACMA: Cheaper in the long run to use servers, suggests a desk-top hard drive, such as their 300 gig Macstore server, which has been operating for 3 years without a failure.
CD-ROMs more labor intensive, need to set up the burns, the cataloging system for the images and disks, store and track the disks, re-create contents if mistakes are made in labeling an image on a disk.
About DVDs:
From Richard Urban, Operations Coordinator at the Colorado Digitization Project: I think the problem with DVD is less the stability of the media, but in the encoding format. Currently there is DVD-R, DVD+R, DVD-RW, DVD+RW. It’s the VHS or Beta problem all over again. In theory these are supposed to be interoperable, but as the article below suggests there are conflicting results on whether theory is reality.
DVD Compatibility: It’s as Ugly as Ever http://www.pcmag.com/article2/0,4149,651657,00.asp
At the moment we’re still recommending people stay away from DVD and stick with Cd-R for longer-term storage (along with copies maintained on CDP servers).
From Andrew Schuricht at the Las Vegas Springs Preservation Project: Can't say I know what comes after DVD. The last I heard, the standards bodies were talking about increasing DVD storage capacity, presumably to store HDTV quality video.
Personally, I'm still a fan of the RAID array PLUS off-site backups on removable hard disk drives. I don't see the IDE compatible drives going away any time soon. There's been a technology competitor there for a while (SCSI), but that hasn't managed to supercede the good old IDE HDD in...what... 15 years?
Plus, keeping your data available makes moving it to the next technology much easier. If all my images are on a DVD and I want them on a new format in 25 years, I have to find a DVD drive, load the images onto my HDD and then transfer them to the new media. If I kept them on live storage, however, this would happen pretty much automatically as I upgraded my storage servers.
From Erik Christman at the Nixon Library: IMHO I think removable HD for media storage are the way to go in addition to CD archiving,, at a little less than $1.50 US per gig of storage, it is almost cheaper than DVDRs.. We use a Western Digital removable unit to backup image and exhibition files, besides burning CDs of the files. before moving the files off our server at or around the end of every year.
From Amalyah Keshet at the Israel Museum:
Kodak doesn't make the Ultima Gold anymore. (That should give you an idea of the problem with digital storage media...) Mitsui is now recommended. The suggestion that removable HD is better sounds good to me. There's a lot about this on the ImageLib listserv right now.
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