Every time my fancy modern computer crashes, I’m reminded of a scene from a Star Trek episode circa 1990. Captain Picard, finding himself in some life-and-death pickle or other, cleverly issues an S.O.S. by inputting computer code into his android crewmate, Data. That message, a humble binary command, is later found by the crew so the show can end on time.

If only it were so easy to raise a crashed Mac. But the more profound message here lies in the subtext: that 24th-century computer programming will be based — just as it is now — on binary mathematics.

So, is that just a bunch of Hollywood hooey crafted to sell Excedrin commercials? Hardly. A dozen years after showbiz writers posited this theory and 63 years after the first electronic computer was invented, binary still rules. And that’s the beauty, as well as the frustration, perhaps, of digital data. The foundation never changes, which is kind of a relief, but the recording media — well, that’s another story.

Connect the dots
Let’s start with binary. First of all, what is it? Quite simply, it is interminable strings of ones and zeros, and it is the only language computers actually understand. It’s also known as machine language. Binary’s ones and zeros form digital bit streams that trigger on/off (or up/down) electronic signals that ultimately drive computer functions. The one and zero bits form complex codes that are managed with assemblers, or high-level commands, so that the machine language is transparent to programmers and easier to deal with (although programmers may certainly choose to write code in binary, if they don’t have a life). Programs are merely binary code compilers.

Every electronic file — regardless of origin or how it may be humanly manipulated at higher programming levels — remains a binary file at its core. Taken all apart, then, every digital image consists of blocks of ones and zeros; these are written as raised spots and pits (on optical media) or magnetized and non-magnetized spots (on magnetic media). So whether you store it on a portable medium, 200 GB hard drive, microchip or, uh, humanoid subsystem, the file itself stays the same: binary. Thus was Capt. Picard able to save the universe, and the increasingly computerized world of healthcare is assured a digital file continuum.

The very first computer to run on binary was the Atanasoff-Berry Computer, or ABC, built in 1939-1942 by Iowa State University professor John Atanasoff and graduate student Clifford Berry. At 6’4” wide, 45” high, 33” wide, and 800 pounds, it was also the first electronic computer. ABC had 3,000 bits of memory in two banks the size of large coffee cans and could perform one operation every 15 seconds. (Modern computers perform 10 billion operations per second.) It was built from telephone switchboards, 300 vacuum tubes, and a mile of wire. The recording medium was electronically punched cards.

Since then, recording media have evolved a lot, from paper, wax and vinyl to film, magnetic and optical. So while digital content structure remains virtually unchanged, storage for it is anything but.

MOD, MOD world
The type of medium you choose for archiving medical data depends on many variables: what you’re saving, how big it is, whether it will be altered, when you’ll need to access it again, and how much automation you require.

Large facilities and storage service providers started archiving to tape or DVD for reasons of storage capacity, but magneto-optical disc (MOD) technology has found many fans in healthcare. Unlike tapes and hard drives, MO discs are resistant to magnetic fields, which is what initially got them into radiology systems.

“All of the CT and MR machines that were shipped throughout the ’90s had MO drives on board. That’s why it kind of caught fire,” says Mike Sutherland, medical channel manager for TDK Electronics Corp. (Garden City, N.Y.). “The problem was the storage capacity. That’s why the MO group has raced to ship its 14X product, which is 8.6 or 9.1 GB. Some of the large manufacturers have jumped on that now for archives.”

MOD combines laser and magnetic technologies, meaning the discs are written thermo-magnetically and read optically. The new 9.1-GB 5.25” discs have twice the capacity of DVDs. Verbatim’s (Charlotte, N.C.) have an advertised archival life of 40 years, and Hewlett-Packard’s (HP of Palo Alto, Calif.) claim 100 years.

MODs come in both write once/read many (WORM) and rewritable versions. Like other removable discs, MOD as an archive is limited to the capacity of its largest jukebox, which gives only about 2.2 TB of storage using 9.1 GB discs. But that’s fine for nearline hospital storage and long-term storage for smaller facilities.

Rose Honea, R.T.R., R.D.M.S., is the PACS manager at Texas Children’s Hospital in Houston. She says TCH has been using a Philips’ [Bothell, Wash.] MOD archive since implementing its IMPAX picture archiving and communications system (or PACS, from Agfa HealthCare, Ridgefield Park, N.J.) in 1991. “It seems to be pretty reliable. We’re about 99 percent trouble-free. For redundancy, we also copy all our exams over to [StorageTek] 9840 tape.”

She says they do encounter the occasional blown MO disc. “You could copy them twice to MOD, but so many exams fit on that medium that once one is corrupted, there’s no guarantee that all exams are retrievable.”

TCH logs 147,000 exams per year, all of them pediatric. By Texas law, they must be kept for 22 years. The hospital’s network has a powerful 100 base-T gigabit backbone; Honea says it enables PACS users to retrieve both MOD and tape images “in about a minute and a half. If the exam is older than six months, it’s going to take maybe three minutes.” Overall, she says, “It’s working out fine,” although the staggering volume of images the hospital must keep has caused it to consider outsourcing its archival storage.

Tape it to the limit

“Among the least stable media of all time” — that’s what the Council on Library and Information Resources (CLIR, Washington, D.C.) unapologetically called magnetic tape in a paper it published in the late 1990s, Into the Future: On the Preservation of Knowledge in the Electronic Age. “Digital technology … is not ideal for preservation purposes,” deadpanned CLIR when noting the fury of NASA’s Jet Propulsion Laboratory (Pasadena, Calif.) upon discovering that 20 percent of vital data taped from the 1976 Viking Mars mission were corrupted.

Nevertheless, tape is still widely used in medical archiving, its primary attraction being capacity. There are linear technologies such as LTO and DLT, and helical varieties such as DAT, AIT and DTF. Linear records data on tape in a straight line. Helical records data in diagonal stripes across the tape.

One company that swears by linear is StorageTek (Louisville, Co.). Howard Hayakawa, V.P. of StorageTek’s tape drive product line, says, “We sold a helical-based tape drive [Redwood] a number of years back and it was very successful, but it was a very difficult system for us to support.” It was introduced in 1992; the transport’s manufacturer stopped production, and support has since been plagued by unavailability of parts. StorageTek now sells DLT, LTO and its own half-inch tape designs, 9840 and 9940.

Hayakawa says the 9840 “has two reels inside so the tape never really leaves the cartridge; you don’t waste time threading tape. And because the tape is all inside the cartridge, we’ve put half the media in one and half on the other, so you start in the middle of the cartridge. It takes far less time to get to the end. It allows you an average time to data of 12 seconds.” The 9940, by comparison, takes 58 seconds, while LTO and DLT take “more like a minute and a half. If you’re looking for a 25-MB image on the 9840, you can get there in about 13 seconds. For people who really care about [speed], there really is no other solution except [hard] disk, which tends to cost more.”

He says StorageTek customers typically want 9840 for nearline storage, and “midrange drives like the LTO for archiving, because there you’re not quite as concerned about how quickly you get the data back.”

Rorke Data, Inc. (San Jose, Calif.) also chose tape for its RTL archive line, configured with either AIT (the Sony/Matsushita product) or LTO (developed by HP, IBM in Armonk, N.Y., and Seagate Removable Storage Solutions in Scotts Valley, Calif.). LTO stores three-fourths the volume of AIT-3, but its data transfer rate is 27 percent faster (115 GB/hr vs. 84 GB/hr). AIT, LTO and 9840 all claim archival life of 30 years. Rorke also sells archives with DVD and CD.

“We’ve seen DVD more prevalent in cardiology, and tape more prevalent on the radiology side,” says Aaron Blotsky, regional sales manager of Rorke’s medical imaging applications. He says each has merits. “AIT-3, for cost per MB, is still the best archiving medium available today.” One AIT tape holds 100 GB of native data or 260 GB compressed. LTO stores 100 GB native/200 GB compressed. DVD only holds 4.75 GB but gives quicker access, and DVD libraries “are relatively inexpensive and are pretty similar [to tape] until you get to the 5 TB range” due to limitations of jukebox size.

The only problem with today’s tape systems, Blotsky maintains, is that they are “not really an enterprise-class type product.” Because of that, Rorke’s next archive product is based on an entirely new product, Super AIT.

Despite the name, Super AIT from Sony Electronics Inc. (Park Ridge, N.J.), or S-AIT, is not another version of the 8mm helical series. Essentially it’s a longer, wider (half-inch) AIT.

“The question came up: ‘We’re able to pack so much information onto small, thinner tape [AIT], what if we made the tape as big as DLT or LTO — how much would it hold then?’,” says Kevin Handerson, Sony’s director of data technologies.

The answer: 500 GB uncompressed. “Customers who want to archive a large amount of information are looking for a bigger bucket. It’s a little bit slower than AIT, but it’s as fast as any linear tape out there and holds much more. Because the S-AIT cartridge has a single spool, it does have to fully rewind before it’s unloaded or loaded into a machine. But the search time is less than a minute, and then it’s just a few seconds to bring the file up.”

Bigger, faster, roomier. Is there a downside? Only that S-AIT is a proprietary format controlled by one company that aggressively upgrades product. Yes, you’ll need a new drive. (So much for backward compatibility.) For the gun-shy, there are always options.

“We don’t have any proprietary hardware or software,” says Samad Moini, senior executive for storage life sciences solutions at IBM. “Tivoli [an IT management program] is an IBM product, but it runs on Sun, HP, SGI, Windows, and Linux. It’s open. If a customer does not want to use Tivoli, they can use Veritas or Legato [both in Mountain View, Calif.] with our LTO solution and do the same archive.”

In April, IBM succeeded in shoehorning 1 TB of native data onto one of its Enterprise 3590 cartridges, making it the highest-capacity tape extant. It was constructed with advanced material made of super-small particles from FujiFilm (Stamford, Conn.). The drive technology already exists, and the tapes will be commercially available in 4 to 6 years — just about when Sony will have a drive capable of writing 10 TB of data to S-AIT, which the company claims that tape can already hold.

DVD
Does anyone remember LaserDisc, the wanna-be successor of VHS from the 1970s? Does anyone want to?

As big as LDs were (an ungainly 8 or 12 inches), they still had to be flipped over in the middle of a movie because the whole thing wouldn’t fit on one side. And as everyone knows now (especially those whose LD enjoyment of Star Trek IV was impacted by the Leonard Nimoy interview that could only be avoided by programming around it), VHS proved the more endearing, and enduring, medium. And LD? Long since replaced by digital versatile disc, or DVD.

PACS developers have discovered it, too. For purposes of long-term archiving, DVD somewhat successfully addresses concerns about backward compatibility and migration of legacy data stored on less-capacious CDs. DVD’s proponents like to claim that its unpretentious origin as a consumer product guarantees standardization, competitive pricing and easy availability.

DVD did indeed start out that way, when a consortium of film companies, media manufacturers, and computer companies agreed in 1995 to develop a single recording standard with which to control the mammoth (and obscenely lucrative) home video/recorded music/computer applications markets. The media manufacturers, who up until then had been merrily churning out incompatible digital disc formats, organized themselves into the DVD Forum under crushing persuasion by Time/Warner, Sony, Microsoft, Intel, Apple and IBM.

And so the happy DVD Forum drafted the DVD Specification Guidebook, the collection of technology standards by which every manufacturer abides, sort of. The fact is that DVD, at the ripe old age of seven, is evolving at a blinding pace. Despite glowing claims to the contrary, compatibility of its past and future incarnations is hardly a forgone conclusion.

There are three key types: read-only, recordable and rewritable, and that’s where anything basic about it ends. DVD’s detractors are quick to argue that it is not yet a mature enough medium for enterprise use. They may have a point.

DVD-ROM is a high-capacity version of a CD. It became affordable to consumers in 1999, and it began outselling CD-ROM fivefold once companies found they could use it to market movies, video games, encyclopedias, phone databases, and the like. DVD-R is the write-once/read-many version. DVD-RAM is the first rewritable version (introduced by Hitachi, Panasonic, and Toshiba). Panasonic (a division of Matsushita Electric Corp., Secaucus, N.J.) developed a technology that made its DVD-RAM hugely faster others. Unfortunately, the early versions (circa 1998) won’t read double-density DVD-RAM discs, which were introduced right afterward.

DVD-RAM has since been joined by DVD-RW (developed by Pioneer Electronics, Long Beach, Calif.) and the rival DVD+RW (collaboratively developed by Sony, HP, Philips Electronics and Yamaha).

DVD+RW drives will record either video or random-access content, and DVD+RW media can be read by both DVD-video players and the DVD-ROM drives in PCs. DVD-RW is somewhat less compatible with video and PC drives, but its cartridge-based medium makes it more suited to archival applications than to consumer devices.

First-generation DVD+RW will not support DVD+R, although HP and Philips now sell second-generation drives that do. DVD+RW, DVD-RW, and DVD-R drives will neither read nor write to DVD-RAM media, although DVD-RAM drives will write to DVD-RW.

Furthermore, DVD-R comes in two types: DVD-R(A) (Authoring) and DVD-R(G) (General). Each has its own recorder, and they are not interchangeable. DVD-R(G) records with encryption coding that prevents the disc’s content from being copied; DVD-R(A) drives and media are more expensive than General. There also are different DVD types for audio and video.

Additionally, DVD-RAM media come in two styles: Type 1 is sealed in a non-removable cartridge; Type 2’s cartridge can be removed for playback in CD-ROM drives. Most DVD-RAM drives are incompatible with earlier DVD-ROM drives. Fortunately, however, many DVD players will play old CD-ROMs, CD-Is, video CDs, and sometimes CD-Rs, although DVD-ROM drives won’t always read CD-R media.

There’s more: Pioneer DVD products are famously incompatible with all others. To refute this notion, Pioneer commissioned a study last July by Intellikey Labs (Burbank, Calif.). Testing involved 100 domestic and international drives ranging from brand new to five years old. The results, released in September, showed that DVD-R and DVD+R were each 78 percent compatible with all formats, while DVD-RW was 58 percent compatible, and DVD+RW was 63 percent compatible. The test concluded what everyone suspected anyway: The newer your drive, the better your chances are of reading something with it.

For now, though, DVD+R and DVD+RW record 20 percent faster than DVD-R and 140 percent faster than DVD-RW, although the latter is cheaper to buy, easier to obtain, and really holds a lot of stuff. For cardiac, it’s just the ticket.

The Encompass archive from Heartlab, Inc. (Westerly, R.I.) utilizes the DVD-R write-once technology from Pioneer. Why not hard-drive or tape archiving, or even MOD?

“Spinning discs are electromechanical devices. They fail all the time,” says Matt Aitkenhead, Heartlab’s V.P. of technical operations. “You want something that can’t be damaged easily or erased. That’s one of the problems with tape; it’s rewritable. Just because a medium is fast doesn’t mean it’s a well-designed archive. Most medical archive technologies utilize a third-party piece of software not specifically written for managing big cardiac images [often a gigabyte or more]. They’re just a generic jukebox manager. It doesn’t matter how fast the mechanism is; that’s very inefficient.”

Aitkenhead says that due to consumer demand for high-definition TV, which requires more storage than today’s DVDs offer, the DVD Forum “is very aggressively developing higher-capacity DVD. We anticipate the price per storage unit to be far below that of anything else. It’s really going to change the medical storage story.”

In September, Sony cranked everything up a notch by introducing Dual RW, the first drive to support both DVD+RW and DVD-RW. It also supports 24X CD-R and 10X CD-RW using high-speed CD-RW discs. Though intended for the consumer home-video-to-disc market, it is also the first drive to support 4X DVD-R (a much-anticipated rewritable medium that will be on the market soon), making Dual RW the fastest DVD rewritable drive available. It will likely find its way into enterprise systems soon.

Everyone with 8-track players, raise your hand
Of course, paper’s a pretty good archiving medium too. CLIR says it lasts up to 500 years, and microfilm up to 200 years, while “some magnetic tape [and] many optical disk media … are not reliable after five years.”

It’s difficult to argue. If the office intern uses a paper file for a coffee coaster, you may sustain a blotch. Park hot java on the file server, and your data are history.

Electronic storage is more fragile than vendors want you to know. Magnetic media can suffer from degradation of signal level from age and head wear, and magnetic fields can easily corrupt their contents. Optical disks are susceptible to surface scratches; breakdowns can occur between the layer where data are stored and the protective layer; also, the protective layer can cloud up and prevent reading. Tapes tend to oxidize, corrode, become brittle, and delaminate when their magnetic coating separates from the backing. Cassettes will break if dropped. The National Institute of Standards and Technology (Gaithersburg, Md.) says a 20-year lifespan is as much as you can expect for magnetic tape, even under ideal storage conditions.

The bigger challenge to data preservation, however, is in how long any given storage medium will be of any practical use. In Into the Future, CLIR points out that in 1976, when the National Archives requested data from the 1960 census, it took the U.S. Census Bureau three years to comply. Why? Because it no longer had machines that could read the 16-year-old magnetic tapes.

To get an idea of what tomorrow’s deadwood will be, just talk to Yves Martel, president of TomoVision (Montreal, Quebec). He developed SliceOmatic, specialized software used by medical researchers to analyze CT slice sets. Their problem? “They have new PAC systems that will only accept DICOM images,” explains Martel, “they’re stuck with all these old magneto-optical discs or tapes or whatever, and they need to transfer the data.” That’s why Martel designed a companion program called ReadOmatic. It deciphers a wide range of abandoned proprietary storage formats.

“The one my clients ask for most is the DAT format from GE; the second would be the Siemens format. Most of the people who have old magneto-optical discs have Pioneer; the Pioneer drives only read Pioneer discs. Then you have the old half-inch reel tapes [a 50-year-old technology], and QIC [quarter-inch cartridge] produced for UNIX and used up until a few years ago.”

Sound familiar? Then you’ll be glad to know ReadOmatic is available free on Martel’s Web site, www.tomovision.com.

Want to migrate data from one type of tape to another? “It’s usually a fairly big deal,” says StorageTek’s Hayakawa. “There’s a software we resell, called ASM [Application Storage Manager], to move it using the automation of the library. Without it you end up having to do manual media migration, which is very painful if you’re talking about 4 or 10 or 20 TB; you just don’t even want to think about that.”

So where does that leave media with 3 to 10 decades of shelf life? “The 30-year retention of tape media is valid [with] proper storage and handling. Round reel tapes have lasted for almost 30 years,” says Monte Holmes, senior account manager of the data storage group at Ovation Data Services, Inc., a Houston data recovery company. “Unfortunately, no tape drive technology or embedded format will be available for 30 years. As disk drive storage capacity requirements increase, tape capacities increase rapidly, leaving all tape technology obsolete, often in less than a couple of years. The chances of reading any tape media after 30 years without duplicating the original environment are very low.”

Last one on the holodeck is a rotten egg.