ING will purchase a DVD archive system before the end of 1999. The choice of DVD format is discussed and a shortlist of suppliers chosen based on a their ability to supply a system that meets the capacity, format, software and delivery requirements. Total cost of hardware and software is approximately £50,000. A project plan lists the detailed management of the project to ensure the archive is fully documented, commissioned and tested before daily operations commence. This will take 17 weeks to complete.

The NWO has generously sponsored the purchase of a DVD library to improve on the CD-Tower. Storage will increase from 660 MB per CD to 9,400 MB per double sided DVD-R, and assuming the library will hold 650 DVD-Rs instead of 500 CDs, an almost ten fold increase in data storage will occur. 

The use of DVDs for storing astronomical data is new but not original. The European Southern Observatory are using a Pioneer 100 slot DVD library controlled by custom written and adapted "CDRecord" shareware that creates UDF formatted data. However, this is not maximizing the capacity potential of a DVD disc. 

A parallel DVD system is required by CASU in Cambridge, UK, for their Sky Survey Archive. Development of this system will be done in parallel with CASU's systems because the prime developer of the current CD-tower software, Jim Lewis, is responsible for the CASU implementation.  In a parallel procurement program, ING will purchase the CASU DVD library and install it in Cambridge. 
 

• Maximum possible data storage is required for each DVD. Select the format offering the highest capacity and select the storage library offering the highest number of DVDs. Ensure a disk flipping mechanism is installed in the library to enable the recording of data on both sides of each DVD.
• Install a prime and a secondary DVD library so that a single library's robotic mechanism does not become a possible single point of failure. Fully equip the prime DVD-library and minimally equip the second. 
• The DVD hardware and software must be upgradeable to DVD-RW in case this becomes the market standard.
• DVD-R data will not be written using the industry standard UDF format, which was developed for read/write media. Instead, manufacturers will need to create new software applications to write DVD-R data. A typical supplier, K-Par, is enhancing its Archimedia product, that ING already uses on its CD tower, with UDF support.
• Each DVD library requires its own UNIX server to manage the SCSI bus and preload data. Use ING standard Sun Ultra 10 computers to control the library, running the latest version of Solaris 7.
• The Sybase RDBMS on orion will control CD and DVD libraries. Therefore the DVD library's virtual file system will be shared by its UNIX server and mounted on orion. 
• Use the secondary DVD library as a test environment for application development, debugging and operating system upgrades evaluation. Alternatively, use it as an extended library, stocked with DVDs recently removed from the primary DVD library.
• The DVD Library and CD Tower will run in parallel so that ING produces both DVD-R and CD-R discs for its permanent archive. DAT tape (D-tape) archives will be ceased when the DVD-R archive is running smoothly. This was decided by NAW on 2/12/1999.

It is possible that not all requirements may be met, so a compromise system may have to purchased and later upgraded. The internal DVD-R recorders will not be available until March 2000, so the system will be ordered with a single external DVD-R recorder. When the internal drives are available, these external units will be part exchanged for the full complement on internal DVD-R recorders. 

JBOD (Just a bunch of disks): the costs of disk arrays is plummeting to the point where a 3.2 TB of storage costs about £65k. However, the data still has to be archived onto a DVD or DAT tape. 

DLT tape library: no universities are using DLT libraries because of their high start up cost and limited access, so ING must stay with a potentially universal commercial solution such as DVD. 

Upgrade the ING CD Tower: Unfortunately, the existing Pioneer CD library is not upgradeable to DVD. 

Other DVD formats: DVD-RAM, DVD-ROM, DVD-RW, DVD+RW There are four recordable versions of DVD-ROM: DVD-R, DVD-RAM, DVD-RW, and DVD+RW. DVD-R can record data once (sequentially only), while DVD-RAM, DVD-RW, and DVD+RW can be rewritten thousands of times.  The three erasable formats (DVD-RAM, DVD-RW, and DVD+RW) are essentially in competition with each other. The market will determine which of them succeed. DVD-RAM has a head start of more than a year.  DVD-RAM (2.6 GB) currently looks like the format of choice for the high consumer market, with a dual layer recorder costing £300 and saving 5.2 GB of data using the universal data format (UDF). However, DVD-RAM discs cannot be read by the earlier generation of DVD-ROM drives. Moreover, disks are kept in disk caddies to protect them, and these cannot be inserted into DVD-ROM drives.  Confusing this even more is  DVD-RW and even DVD+RW (3 GB now, and 6 GB later) from Sony, Philips and HP, who are intent on breaking away from the central planning body, the DVD Forum. And just as it looked as if it could not get any more complicated, DVD-Audio, DVD-Video and DVD-Data are also being developed. 

DVD-R: used for creating write-once DVDs, requires a £5k recorder, and can be used to burn single-layer DVD-ROM discs. First generation capacity was 3.95 GB, but was later extended to 4.7 GB. Matching the 4.7 GB capacity of DVD-ROM was crucial for desktop DVD-ROM and DVD-Video production. Their capacity increases to 9.4 GB with the addition of a "DVD Flipper" within the library that turns over the DVD-Rs. Anecdotal evidence from suppliers is that only Pioneer offer DVD-R recorders at present, so the market is restricted. DVD-R flippers are not available at the time of writing. 

Manufacturers of libraries meeting some of the previously listed requirements are Pioneer, Plasmon, Cygnet, Chess DAX, JVC, Kodak and NSM. 

Pioneer, whose CD-R tower has provided such reliable service, is obviously a front runner. Its  track record  operating at 8,000 feet altitude and low humidity is very important.  Pioneer's DRM-7000 Flexlibrary DVD data storage system is a multi-drive library. Each of its 16 storage slots space can either be used for  pairs of CD drives or  packs of 50 DVD discs. Based on existing demand for disk writing capacity, a combination of two DVD-R records and two DVD players have been selected, leaving 13 magazines of 50 disks. 

Plasmon only offer a 480 disk system, compared with Pioneer's 650. UK distributors such as Storage Technology who supplied the CD Tower are concentrating on Plasmon's range instead of Pioneer's . It is important not to purchase equipment that is in danger of being discontinued because of market competition. 

Cygnet's InfiniDVD contains 500 DVD-RAM discs, but there is no announcement of DVD-R yet. 

Chess smartDAX from Holland has a 700 CD Tower with an elegant rotator mechanism holding eight CDs in one large circular ring. Solaris software drivers and an XFS file system derivative make it an interesting candidate for a DVD-R product. However, there are not able to offer a  DVD-R product  in 1999. 

JVC, Kodak and NMC are still considering DVD-R development and have opted for DVD-RAM or DVD-RW instead. Some only offer 100 slot systems or Windows NT-only driver software. 

• Pioneer DRM-7000 disc changer
• Pioneer S201 DVD recorder
• Pioneer DVD-D7361 DVD-ROM player
• Pioneer DRM-7000 Disk Turnover Module 
• Pioneer DRM-Al751 50 disc magazine
• Pioneer DRM-AH721 20 disk hypermagazine
• K-Par DVD-Creation DVD mastering software
• Sun Ultra 10 computers, discs, DAT
• 3 com managed 100base-T switch

• 1 off 720 slot DVD library containing 2 DVD-R drives and 2 DVD-ROM drives
• 1 off 720 slot DVD library containing 1 DVD-R drive and 1 DVD-ROM drive

• 1 off software application that writes the DVD discs in the DVD library. It should use the  NFS protocol so that the DVDs appear as mountable UNIX file systems.

• 1 off Ultra 10 computer with 512 MB RAM, 9 GB internal disc and 36 MB external disc, DDS-3 DAT, SCSI card, 19 inch colour monitor, keyboard and mouse
• 1 off Ultra 10 computer with 512 MB RAM, 9 GB internal disc and 18 MB external disc, SCSI card, 19 inch colour monitor, keyboard and mouse
• 8 port 100 Mbps managed switch
• Patch panel.

• Ten fold increase in on-line storage capacity of the Engineering Archive.
• Development of a fully documented and commissioned archive system under supervision of ING staff.
• Lower cost per GB of storage than current CD costs after DVD-R costs stabilize in a year's time.
• Less frequent changing of media in tower.
• Prime and standby system for recovery from possible single point of failure in the tower's robotic controller.
• Upgrade of Sun computer to latest Ultra 10 from the performance-limited Ultra 1, orion on the CD tower.
• Redesign of mastering process to perform simultaneous retrieval of data from telescopes, format conversion and DVD mastering.

Nic Walton has produced much of the preliminary research and cost estimating. Thanks are due to him for compiling sets of statistics, web addresses, suppliers and industry news and for turning this plan into reality by constantly pressing for its completion.