Alan Freedman -- The Computer Language Company - Computer Desktop Encyclopedia
Computer Desktop Encyclopedia
Longest-Running Tech Reference on the Planet

A CDE Definition

You'll love The Computer Desktop Encyclopedia (CDE) for Tech Term of the Day (TTOD)

LOOK UP ANOTHER TERM


first hard disk

See RAMAC.



RAMAC

(Random Access Method of Accounting and Control) The first hard disk computer, introduced by IBM in 1956. All 50 of its 24" platters together held a total of five million 8-bit alphanumeric characters (5MB). Weighing more than a ton, RAMAC was half computer, half tabulator, and more than a thousand units were built until production ceased in 1961. The RAMAC had a drum memory for program storage, but its I/O was wired by plugboard. The machine was a major breakthrough as all prior computer storage used magnetic tape.

RAMAC leased for USD $38,400 per year, equivalent to roughly $300,000 in 2016 dollars. About a third of the cost was RAMAC's "huge" disk system. However, 60 years later, that same amount of storage cost less than one thousandth of one cent on a multi-terabyte hard drive. See tabulator.






The RAMAC, 1956
At 2,000 magnetic bits per square inch, IBM's RAMAC was an amazing technology in the 1950s. Each 24" platter held a whopping 100,000 characters (no bytes then) for a total of five million characters. (Images courtesy of IBM.)






RAMAC Resurrected
In 1994, IBM reinstated the RAMAC name for its hard disk arrays. In 38 years, areal density vaulted from 2,000 to 259,500,000 bits per square inch, and access time decreased from 600 milliseconds to 9.5. (Image courtesy of IBM.)






Personal Use Only

Before/After Your Search Term
BeforeAfter
FireWire hard drivefirst-level cache
FireWire portfirst memory
Firey enginefirst mile
firmwarefirst miniature drive
firmware updatefirst-party cookie
firmware upgradefirst-person shooter
FIRSTfirst programmer
first boot sequencefirst screen
first computerfirst-time reader
first-generation computerfirst-time user

Terms By Topic
Click any of the following categories for a list of fundamental terms.
Computer Words You Gotta KnowSystem design
Job categoriesUnix/Linux
Interesting stuffPersonal computers
InternetIndustrial Automation/Process Control
Communications & networkingAssociations/Standards organizations
HistoryDesktop publishing
Audio/VideoGraphics
MainframesSecurity
ProgrammingHealthcare IT
System design