Steven C. Barr wrote: > > ----- Original Message ----- > From: "David Seubert" <[log in to unmask]> > > I may have mentioned this before in this forum, but the UCSB Library > stores > > its digital content on disc arrays from Wideband Systems that run RAID 5. > > We currently have 9TB of digital data in the Alexandria Digital Library, > > mostly geospatial data and air photos, but soon audio with our cylinder > > digitization project. Even with RAID 5, we have had a simultaneous failure > > of multiple hard drives, which required restoring the drives from tape > > backup. We have 40TB of tape backup and we also backup to the San Diego > > Supercomputer Center. Imagine what happens when the hard drive fails (and > > they will) and you don't have an alternate backup. It's gone. > It would appear that we have to be like the chap who wore both belt and > suspenders! > We know that storage media have a specific and non-infinite life span...we > also > know (I do, from bitter experience) that active storage media (i.e. hard > drives) > have a similar non-eternal expectancy. Further, we know that the original > information > usually is in a non-eternal form, even ignoring the possibility of disaster > (the > shellac record may be the closest thing to long-term indestructibility) In > fact, I > have seen a number of 19th-century tombstones that prove the fallacy of > "carved in stone!" > > We could convert the data to digital form as accurately as possible, and > then store > it on both hard drives and CD-R or DVD-R, using each of the two as sources > for > regularm refreshing of the other. Alternatively, we could perfect shellac > DVD-R's...? > Steven C. Barr Tape, floppies, and phono records all require physical contact between the storage medium and the pickup. Hard drives have only a microscopic gap. Only optical media, such as CD and DVD discs, have a significant gap between the media and the pickup. Tape has an additional disadvantage in that data surfaces are in physical contact, under tension, during storage. These are significant considerations. Jerry Media Sciences, Inc.