A CDE Definition
(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
A machine that added up numerical data in punch cards. Tabulators were used to prepare invoices, checks and "green-striped" reports as late as the 1970s. Invented by Herman Hollerith in 1890, his tabulator displayed the totals on dials. Subsequent models were able to perform additional arithmetic operations as well as print the results. See Hollerith machine, punch card and continuous forms.
First Tabulator - 1890 U.S. Census
A Tabulator in the 1960s
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