History of Magnetic Storage

Before there was magnetic storage for computers, the primary storage medium was punch cards (paper cards with holes punched in to indicate character or binary data), originally invented by Herman Hollerith for use in the 1890 Census. What amazes me is that I missed contact with punch cards by about a year; the college I went to discontinued using them during my freshman year, before I was able to take any computer-related courses. I have to believe that this was more a reflection on their budget and lack of focus on current technology at the time (in 1979, there really weren't many punch-card readers being used in the field) than it is on my age! Although long obsolete in computer use, punch cards in various forms are still used in older voting equipment.

The history of magnetic storage dates back to June 1949, when a group of IBM engineers and scientists began working on a new storage device. What they were working on was the first magnetic storage device for computers, and it revolutionized the industry. On May 21, 1952, IBM announced the IBM 726 Tape Unit with the IBM701 Defense Calculator, marking the transition from punched-card calculators to electronic computers.

Four years later, on September 13, 1956, a small team of IBM engineers in San Jose, California, introduced the first computer disk storage system as part of the 305 RAMAC (Random Access Method of Accounting and Control) computer.

The 305 RAMAC drive could store 5 million characters (that's right, only 5MB!) of data on 50 disks, each a whopping 24" in diameter. Unlike tape drives, RAMAC's recording heads could go directly to any location on a disk surface without reading all the information in between. This random accessibility had a profound effect on computer performance at the time, enabling data to be stored and retrieved significantly faster than if it were on tape.

From these beginnings, the magnetic storage industry has progressed such that today you can store 500GB or more on tiny 3 1/2" drives that fit into a single computer drive bay.

IBM's contributions to the history and development of magnetic storage are incredible; in fact, most have either come directly from IBM or as a result of IBM research. Not only did IBM invent computer magnetic tape storage as well as the hard disk drive, but it also invented the floppy drive. The same San Jose facility where the hard drive was created introduced the first floppy drive, then using 8" diameter floppy disks, in 1971. The team that developed the drive was led by Alan Shugart, a now legendary figure in computer storage.

Since then, IBM has pioneered advanced magnetic data encoding schemes, such as Modified Frequency Modulation (MFM) and Run Length Limited (RLL); drive head designs, such as Thin Film, magneto-resistive (MR), and giant magneto-resistive (GMR) heads; and drive technologies, such as Partial Response Maximum Likelihood (PRML), No-ID recording, and Self-Monitoring Analysis and Reporting Technology (S.M.A.R.T.). Today, the combined hard disk drive operations of IBM and Hitachi (called Hitachi Global Storage Technologies) is arguably the leader in developing and implementing new drive technology and is second in sales only to Seagate Technology in PC hard drives.