Ok, I’m early, but this is a big birthday. Steven Levy, one of the best tech journalists in the business, notes in Newsweek that September 13, 2006 will mark the 50th anniversary of the first disk drive ever shipped, the IBM RAMAC (Random Access Method of Accounting and Control).
Weighing almost a ton, as big as two refrigerators, holding a whopping 5 MB, the RAMAC’s 50 24-inch disks spun at 1200 RPM. They didn’t spec the access time, but given that rotational latency alone was 25 milliseconds and disks the size of Kansas, it was probably on the order of 100ms. Yet with three independent access arms, I’d guess the could could manage about 20 IOPS. Coolness factor: the disks were behind glass, so you could see them. Pictures, including the drum storage, here.
The RAMAC’s huge capacity supplemented by the host computer’s 600 digit (as I recall, IBM digits in those days were only 6 bits) core memory, and the 20,000 digit magnetic drum local memory. The magnetic drum had fixed heads and spun at 12,500 RPM with a mere 2.4 millisecond access time – over twice that of today’s fastest disks. Given the host’s blazing 125 KHz clock, that was pretty good.
What tends to be forgotten is that memory, both main and secondary, has been the largest single barrier to digital computer development. Building processors, even with vacuum tubes, wasn’t that difficult. Keeping them fed with data and instructions was and is.
Project Whirlwind, the world’s first interactive computer system (you know, like the one you are reading this on), almost failed when the MIT engineers couldn’t figure out a workable storage system. Finally they kludged something together and declared victory.
The RAMAC began a long and profitable business for IBM providing storage, or “rotating rust” in the vernacular. IBM maintained a powerful hold on the business until the dark days of Ellen Hancock’s leadership of the storage group (see Daddy, tell me again how little EMC beat giant IBM . . .). IBM’s Almaden Research Center has led the way in disk storage research for years. IBM’s technical contributions to storage are huge and worth remembering, starting with the RAMAC.