It seems that all trails to magnetic disk storage can be traced back to IBM. The mainstream hard disk drive of today, for example, was a 1973 IBM innovation that set the standard for the next decade and some sources suggest that IBM's original play in PCs in the 1980s was actually just a ploy to sell disk drives. IBM is credited with fielding the first magnetic disk drive back in 1956 when mass storage meant punch cards and magnetic tape drives, the same year Thomas J. Watson stepped down, after leading the company for 45 years, and Thomas Watson Jr. took over as chief executive officer. As in other areas where IBM research led to technology that defined a market, the company's mass-storage clout came from its strong R&D foundation.

IBM opened its first research laboratory, the Watson Scientific Computing Lab, in 1945 in Manhattan, a year after introducing the Mark I, which it claims as "the first large-scale calculating computer." The lab was devoted to pure science from the get-go. Said Watson Sr. at the time: "The research and instructional resources of the lab will be made available to scientists, universities and research organizations in this country and abroad, and special cooperative arrangements will be made with scholarly institutions."

The Mark I had, in fact, been cooperatively developed with Harvard University. It was, by the way, about 50 feet long and almost 8 feet high, weighed nearly 8 tons and it took around six seconds to perform a multiply.

Over time, the IBM Research Division, now seven labs strong, has tapped into many disciplines at different labs that converged on mass storage. Time and again, the company has demonstrated a powerful one-two punch, commercializing one generation of technology while its researchers establish the principles that lead to the next, as the magnetic disk juggernaut has shrunk real estate and sent capacity soaring over time. Mass-storage R&D is now centered at The Almaden Research Center in San Jose, Calif., established in 1986 as a "joint program to incorporate new scientific achievements into IBM drives," and closely coupled to IBM's Storage Systems Division (SSD), also in San Jose.

That first commercial magnetic disk drive, introduced in 1956 as the RAMAC (Random Access Method of Accounting and Control) 305, was developed by IBM in San Jose. Roughly the size of two refrigerators, it used double-sided disks with a two-foot diameter and required 50 of those disks to store just 5 Mbytes of data. Over time, the size of magnetic disks would scale down to 14 inches, 8 inches, 5-1/4 inches, 3-1/2 inches and below as IBM continually reinvented the technology. The company's most recent offering is the so-called "microdrive," aimed at providing such things as digital cameras and handheld devices with up to 340 Mbytes in a 1-inch drive about the size of a matchbook, weighing in at 0.7 ounces and capable of operating from two AA batteries.

Over the decades, "improvements in all aspects of disk-drive technologies have yielded a millionfold increase in the amount of information that can be stored in a given area of disk surface, a 3,000-fold speedup in the amount of data a drive can read and write in a second, and a more than 500,000-fold decrease in the inflation-adjusted cost of storing each bit of data," according to an IBM Research paper co-authored by Michael Ross of the Almaden lab. "Nearly all of the technical innovations that made this progress possible originated from within IBM," he said. "And today this rapid pace of innovation and improvement is actually accelerating."

The first Winchester disk drive, introduced in 1973 as the IBM 3340, doubled the density of the time to 1.7 Mbits/inch2. Its read/write heads were made of machined ferrite-ceramic with hand-wound coils. In 1969, however, IBM Fellows David Thompson and Lubomyr Romankiw at the Thomas J. Watson Research Center, which had been established in 1961 in Westchester County, N.Y., pioneered the technologies behind sleek thin-film heads whose coils were formed by photolithography and plating techniques.

"This development not only led to higher-capacity and higher-performance disk drives but also provided critical manufacturing expertise that would enable future developments to be quickly incorporated into IBM products," said an IBM spokesman.

Disk drives are more than just read/write heads, of course. Advances came in mechanics, electronics, software and disks as well. "While most of IBM's data storage research is conducted at Almaden, groups throughout the [Research] division make significant contributions," Ross said. "For example, servo writing, mechanical shock tolerance and metal plating technologies from Watson; servo optimization from Tokyo Research Lab [established in 1982]; and pioneering signal processing research from Zurich Research Lab." IBM's other research labs are found in Austin, Texas; Beijing; Haifa, Israel; and Delhi, India.

IBM SSD fielded drives with thin-film heads in 1979, and in 1988, the company discovered a principle that would take magnetic disk technology to yet another level, moving beyond the inductive sensing technology hitherto used for read operations.

The MR (magnetoresistive) sensing technique was discovered by two European IBM scientists at the Zurich Research Laboratory, established in 1956 in Rueschlikon, Switzerland. Inductive sensing remains in use for writing.

"As revolutionary as the thin-film head was, we knew that it would eventually run out of steam," said IBM Fellow Ching Tang in Michael Ross's report. "So we were already trying to learn how to make dramatically more-sensitive read-element sensors." The incentive to pursue MR sensing, said Ross, "was substantial: MR read elements were expected to be three to five times more sensitive than inductive designs while performing just as well with the smaller-diameter disks that were becoming popular."

At the time, the MR principle was being used for "low-density, low-data-rate applications such as badge readers and magnetic tape players," Ross said. "But for years, scientists trying to make MR heads for the much more-demanding disk-drive environment encountered severe problems with linearity and noise."

A team of scientists and engineers from Almaden and SSD lab carried forth the development and fielded the first drives with MR heads in 1991, then MRX (MR extended) heads and, most recently, GMR (Giant MR) heads.

The 'giant magnetoresistive' head gave IBM the world data density record of 10 gigabits/inch2.

Ross said "the daunting improvements needed to mass produce the required very thin films [are] an example of Research's many contributions to IBM's manufacturing capabilities."

The MR principle, now the dominant head technology, enabled SSD to roll out the first 1-Gbyte 3-1/2-inch drive in 1991, while at Almaden, researchers were opening "the door for affordable applications by showing the spectacular GMR effect could also be achieved in more easily made sputtered, polycrystalline multilayer samples," said SSD's Jim Belleson and Almaden's Ed Grochowski in an IBM white paper.

By 1997, MR technology had stretched to pack 5 Gbytes into a 2-1/2-inch drive for portable computers and 8.4 Gbytes in a drive for desktops-at a record density record of 1.74 Gbits/inch², more than four times the average at the time. The 3 Gbit/inch² MR demonstrated by IBM Research in 1994 was commercialized by IBM SSD in 1997. IBM Research had, meanwhile, demonstrated a 5-Gbit/inch² MRX in 1996.

Because of the small volume of MR/MRX heads, however, "A density of 5 Gbits/inch² is thought to be close to the limit of MR technology," said Ross, so GMR with its unique "spin valve" architecture was conceived in "an exceptionally broad and rapidly productive research effort" at the Almaden lab.

In late 1997, IBM SSD announced a 3-1/2-inch GMR drive packing a 16.8-Gbyte capacity and a density of 2.69 Gbits/inch², followed in early 1998 by a 4.1- Gbit/inch², 6.48-Gbyte 2-1/2-inch drive.

Shortly thereafter, IBM Research demonstrated GMR at 11.6 Gbits/inch2 in the lab, and by summer 1999, SSD was shipping drives with up to 10.1 Gbits/inch². By that time, Research had demonstrated 20 Gbits/inch², following with 35.3 Gbits/inch² in October last year. The improvement behind this latest achievement, according to the company, lies in new metal-alloy coating for the disks. John Best, vice president of technology at SSD, said the new media can be manufactured with existing production equipment.

"At 35-gigabit density, every square inch of disk space could hold 4.375 gigabytes," said Best, "nearly as much data as a 4.7-inch DVD-ROM or seven CD-ROMs (each 650 megabytes). At this record density, a single desktop drive platter (3-1/2-inch diameter) would hold nearly 50 gigabytes; a notebook platter (2-1/2-inch) more than 20 gigabytes and a microdrive (1-inch) more than 2 gigabytes."

That's not to say, of course, that GMR — or magnetic storage in general — will never tap out, and IBM Research is, no surprise, working on new mass-storage technologies, notably holographic storage, which promises an order of magnitude greater capacity and speed.

Traditional holography stores different perspectives of one image at different angles; for mass-storage applications, each angle stores a different data page. "Unique to holographic storage is the ability to perform essentially immediate data searches through huge digital libraries by simply illuminating the media with all of the stored informnation (a holograph) with a pattern of the requested information," a spokesman explained.

The company's Holographic Data Storage System project has demonstrated the ability to store 10,000 such pages, each holding 1 Mbit, "in a crystal the size of a sugar cube." Demonstrated access time to a page is 1 trillion bits/second.

The Century of the Engineer: Companies that made a difference