The storage of archive materials on discrete media is a task of forbidding complexity and expense. There are no easy cheap options for the long term care and storage of individual tapes, cassettes, or discs, and when volume is increased the stock management and housekeeping associated with large amounts of assets are considerable.
Moving assets into mass storage brings key advantages in the storage are because of a number of factors:
Density: When assets are held as files there does not need to be a one to one mapping between assets and media items- many files can live on a single disk, or striped and spread between multiple disks in RAID and similar technologies. Less space used results in lower costs. Further, direct manual access to the physical storage media is not required, obviating the need for extensive walkways and other areas for personnel. Even storage systems based on removable media can use robotics instead of manual logistics to reduce the space required by large amounts.
Whilst discrete media will always require separate physical items for each stored asset, a minimum size for an archive holding a set number of items remains fixed. With a mass storage system, technology advances in storage density can deliver continual reductions in the space requirements for your archive.
Media Cost: By moving to commoditised, IT industry storage equipment in a mass storage solution, archives can be released from the high costs associated with specialised Audio Visual media. The IT storage market is large, fiercely competitive, and drives some of the world's most aggressive research and development. To be able to capitalise on the most cost effective products of this market, archives have to switch to mass storage technologies.
Disaster Recovery: The low cost, and ubiquity of mass storage facilities, and the network technologies that can connect these facilities, at last open the option to archives of maintaining full remote duplicates of their collections. Depending upon the value of the assets stored, the costs of duplication and remote storage may well be justifiable within budgets previously directed to the maintenance of large single discrete storage facilities. With Outsourced off site specialist Storage Service Providers, such recovery abilities should at last become affordable to smaller archives.
Stock Management: In an archive based upon discrete assets, the removal of items from storage is an unavoidable part of the process associated with access- items are removed from storage to be loaned out, to be dubbed onto a browse quality review copy, or to be duplicated or migrated. Items stored as files in a mass storage system need never leave the archive. Digital copying allows faultless duplication to any standard required, whilst the item remains within the storage system at all times. Stock management is a meaningless concept in such a system.
Varying Value: You may call them the vaults, the back rooms, the dusty cupboards, but most archives have an area, a section of their collection that is less often accessed, less requested, and arguably less valuable than other areas. We hold on to these collections for a variety of reasons; a speculative investment in the future, a concern that these may be the last examples of their kind, or sometimes simply because we can. The PrestoSpace project includes efforts to design digitisation processes that will be as affordable as possible, but you may not wish to invest the same amount in the storage of the 'back room' collection as they might in their main, heavily used material. After all, that investment will be aimed at offering highly resilient, speedy access and delivery- not necessarily factors that matter much in this case. In fact lowest possible cost is almost certainly the main factor here.
Mass storage systems need not be utterly homogeneous though. It is quite possible, and in fact quite common, to have multiple tiers of storage in a Hierarchical Storage System. At the 'top of such a hierarchy is the very fast reaction memory, a cache of frequently, recently requested items. This may be solid state memory, relatively expensive, but very quick to deliver content. The next layer down might be fast, high quality hard disk drives. Again, quite quick to deliver files, but the costs will be lower. As we move down the stack, progressively cheaper, slower storage mediums can be employed, to the point where, at the bottom of the stack, removable optical or tape based storage is viable, due to the acceptability of slow access times.
Within a properly constructed mass storage system all these layers of storage can be available to store appropriate content upon, with a minimal impact to the user. Advanced file systems can even spread a single content item across multiple layers of the hierarchy, so that the most immediately required section is available to access whilst the rest loads up. Depending on your archives content, and the use to which your customers put that content, the storage system can be reconfigured to give the most cost effective use of storage possible.
