The 1301 had 13 times the capacity of the RAMAC, and its platters rotated at 1,800 rpm -- compared with a spindle speed of 100 rpm for the RAMAC -- allowing heads to access the data more quickly.
"The difference was that the flying heads were able to be closer than the air-bearing heads. You got more tracks and linear density with flying heads ... and the access time was about a tenth the time," Hoagland said. "It had the kind of performance that allowed hard disks to eventually percolate through the whole computer world."
The 1301 reduced the average read head-to-surface distance of from 1,000 micro inches in the RAMAC to 250 micro inches. A micro inch is one-millionth of an inch. To put that into perspective, a human hair is 2,000 micro inches thick. Today's hard drive heads fly about 10 nanometers off the platter, far narrower than line widths used in semiconductor technology.
From an eight-in. drive in 1979 to a 0.85-in. drive today.
The success of a disk drive "is derived from a mechanical feature," said Hoagland. "By reducing the [read/write head-to-platter] separation, you're constantly scaling the dimensions for higher densities."
Only two years after creating the 1301, IBM built the first removable hard drive, the 1311. The drive system, which shrunk storage technology from the size of a refrigerator to the size of a washing machine, had six 14-inch platters and contained a removable disk pack that had a maximum capacity of 2.6MB of data. The 1311 remained in use through the mid-1970s.
In 1979, Al Shugart, who had helped develop the RAMAC with IBM, launched Seagate Technology Corp., which became the largest disk drive manufacturer in the world.
Innovation floodgates
Soon thereafter, the innovation floodgates opened. The "small form-factor" hard drive was invented in 1980 by Seagate. That 5-in. ST506 drive held the same capacity as the RAMAC (5MB) and could read or write more than 12 documents at a time in less than a second.
In 1983, the now-defunct company Rodime released the first 3.5-in. hard disk drive that held 10MB of data. Twenty years later, Western Digital introduced its first 10,000-rpm Serial ATA (SATA) 3.5-in. drive, the Raptor. That drive, created for data center server use, had 37GB of capacity. The following year, in 2004, Toshiba came out with the first microdrive, a 0.85-in. square form factor that could store up to 2GB of data.
Microdrives spurred greater innovation in handheld devices, such as Apple's iconic iPod. When the iPod was first released in 2001, it had a 1.8-in. hard drive with 5GB of capacity. By 2006, the capacity of the iPod microdrive had grown to 160GB.
That was the year that Seagate and Western Digital introduced 2.5-in. hard drives for data center use with 10,000-rpm spindle speeds. Seagate's Savvio 10K.2 stored up to 146GB of data, or about 28,800 times that of the old RAMAC disk system, and was 8,500 times faster. Western Digital's Raptor X held 150GB. With the increased spindle speed, the drives could read or write the complete works of Shakespeare 15 times over in less than a second.