History: First HDD 55 Years Ago From IBM at 100

IBM Corp. is just celebrating its 100th anniversary as the company was founded on June 16, 1911. Consequently we come back here on one of the greatest innovation in the history of Big Blue and the storage industry, the first hard disk drive, named Ramac 350, in 1956.

But the storage industry dates even further back, to 1890, with the first punch cards, and then with magnetic drums (1951) and tape (1952).

It was on September 14, 1956, however, when IBM published a press release announcing the first computer disk unit, the Ramac 350 (Random Access Method of Accounting and Control), a major component of IBM 305 Ramac computer system.

It was already clear that magnetic tapes could not provide for random access, while drums seemed too expensive and too cumbersome. To attain the capacity of the Ramac, a drum 13 inches in diameter and 42 feet long would have been necessary at this time.

 
IBM 305 Ramac brochure   On July 12, 2002, Currie Munce,
                                                         IBM’s director
                                                     of HDD technology,

                                            holds up Ramac 350 disk platter
                                         and new one-inch IBM Microdrive.

  

                    Ramac 350                        The Ramac weighed
                                                                         over a ton
                                                                 and was delivered
                                                                via cargo airplanes.

  The dual arms used to write or read data

Magnetic heads and rotating disks: enough said
By conceiving a device with magnetic rotating disks read by magnetic heads, IBM set the stage. Everything since simply amounts to evolution.

The Ramac 350, that we look at many years ago at IBM’s San Jose facility, has to be seen to be believed. The unit consists of an enormous device 60 inches (152cm) long, 68 inches (172cm) high and 29 inches (74cm) deep with a gigantic electric motor attached to a solid axis that held 50 coated aluminum disks – or 100 surfaces – one inch thick and 24 inches (610mm) in diameter, for a mere 5MB raw capacity or 4.4 million characters.

Disks were separated by .3 inch spacers, making the height of the stack approximately 20 inches. The stack rotated at a speed of 1,200rpm. Each disk surface contained 100 concentric recording tracks in the outermost 5-inch band, used for storage, which translates to 20 tpi. An NRZI recording method similar to that employed in IBM’s tape drives was aided by a special self-clocking system. Bits were recorded on the inner-most track at 100 per inch (100 bpi) and on the outer-most track at about 50 per inch (50 bpi), densities that permitted 500 encoded alphanumeric characters per track.

“The spacing of the heads from the disk is maintained by an air bearing obtained from minute air jets in an annular manifold surrounding the magnetic elements,” reported IBM at the Western Computer Conference in February, 1956. “The .0001-inch spacing (ultimately, it proved to be 800 microinches. Ed) is held despite the axial runout in the disk so that there is never physical contact between the heads and the magnetic coating.”

More specifically, there were only two heads on the Ramac. To switch access from one disk to another, the two heads were unloaded, removed from the stack of disks and then moved to the desired disk and track. The air bearing that separated the head from the disk was created by an external air supply routed through small orifices in the head carrier.

The Ramac was configured with 50,000 sectors identified by the numbers 00000 to 49999. Each sector held 100 characters (like a punch card), which thus yielded a total of 5 million characters each, taking up 7 bits, or 4.4MB in all. Average seek time was 600ms. Data transfer rate was 9KB/s.

At the time, all drive functions were controlled by the CPU. The first disk controller to manage drive operations did not appear until 1962 (the 7361 controller).

Fourteen prototype Ramac systems, known as 305As, were built for trial use and internal testing. The first delivery to a customer site occurred in June 1956, to the Zellerbach Paper Company, in San Francisco, CA. This file (a term that persisted for many years in IBM jargon, as opposed to ‘drive’) was rented, with an entire system consisting of processor, card punch, printer and console, the whole renting for $3,200 per month, an attractively low price at the time. IBM asserts that the single drive was worth $50,000 or $11,364 per megabyte in 1956.  

99 Notre Dame Avenue
In 1958, the computer system was enhanced to allow for an optional supplementary 350 disk storage unit, thereby doubling the capacity, with a second access arm added to each drive.
 
1,067 model 305s were built in San Jose before production ended in 1961. Among their large customers was the U.S. Air Force, which utilized Ramac for inventory control at a number of airbases.

What led to all of these developments was IBM’s decision, in 1952, to open a small laboratory on 99 Notre Dame Avenue in San Jose, allowing its freshly assembled staff, of 50 or so, a measure of freedom for advanced development. The members of the laboratory (who included the well-known Bill Goddard), under the initial direction of W. Wallace McDowell and management of Reynold B. Johnson, created the novel storage product, referred to then as a ‘magnetic disk file.’  

Winchester
IBM is strongly associated with the entire history of hard disk drives, it’s safe to say, as a firm behind some of the technology’s major innovations until the activity was sold to Hitachi in 2002 for $2.050 billion.

Big Blue introduced an aerodynamically shaped recording head in 1961 that flew above the surface of spinning disks. By permitting heads to remain closer to the disk, this technology led to a massive increase in areal density.

In 1973, Big Blue announced what the industry labeled Winchester technology because its development engineers called it a’ 30-30′ (its two spindles each had a disk capacity of 30MB), the
common name of a rifle manufactured by the Winchester Company. Kenneth
E. Haughton, who led this effort, is reported to have
said: “If it’s a 30-30, then it must be a Winchester.” This development consisted of a lightweight recording head that could land and take off while a disk was still spinning, thus greatly reducing the cost of disk drives. The first Winchesters were the IBM 3340, priced at $87,600 for a 140MB drive.

In 1978, the company received the original patent for a disk array subsystem and then co-sponsored the research by the University of California at Berkeley that led to the initial definition of RAID levels in 1987.

Early in 1990, IBM shipped the first product utilizing PRML. In 1991, IBM released the first disk drive with MR heads.

So it was that, 55 years ago, Ramac was born and with it the HDD industry. IBM, the proud parent, commemorated the event in 1996 by naming a new line of mainframe RAIDs Ramac after those first models.

Official Press Release of Ramac

The first subsystem 305 Ramac, based on the Ramac 350 hard disk drive, was officially announced somewhat discreetly by IBM on September 14, 1956, with a press release that also unveiled a 650 Ramac computer, as well as two other products, including the first electronic typewriter. Earlier the press had been flown to Norfolk, VA, to watch a demonstration of a 305 Ramac system being tested by the U. S. Navy at its Norfolk Supply Center. What follows are excerpts from those product releases, in a statement from IBM president Tom Watson:

“305 Ramac and 650 Ramac, two electronic data processing machines using IBM’s random access memory, a stack of disks that stores millions of facts and figures less than a second from management’s reach. Because transactions are processed as they occur, the fresh facts held in a random access memory show business as it is right now, not as it was hours or weeks ago.”

In announcing the products, Mr. Watson said: “Today is the greatest new product day in the history of IBM and, I believe, in the history of the office equipment industry. These products provide the most significant advancement toward business control and operation by electronics to be made thus far.“

“The 650 Ramac and 305 Ramac both utilize the magnetic disk memory device announced as experimental by IBM a year ago. Both machines are the first of a planned line of equipment designed for high-volume, in-line processing of business data. Transactions are processed continuously, as they occur, instead of being held until a group is accumulated, sorted and batch processed. In a single step, all records affected by a transaction will be immediately adjusted to account for the change.

“The 650 Ramac combines the IBM 650 Magnetic Drum Data Processing Machine with a series of disk memory units which are capable of storing a total of 24-million digits. The 305 Ramac is an entirely new machine which contains its own input and output devices and processing unit as well as a built-in 5-million-digit disk memory. Both machines operate according to a program of electronically stored instructions.

“The monthly charge for 305 Ramac is $3,200. Prices on the 650 Ramac will be announced at a later date. Deliveries on both will start in mid-1957 although several test 305 Ramac’s are being delivered this year.”

Read also:
More on First HDD IBM RAMAC (CORRECTION)
Usable capacity of 3.75MB and priced at $35,750
IBM 305 RAMAC Data Processing System
Random Access Method of Accounting and Control