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Originally designed for the US Navy's Bureau of Ships (a cover for the NSA) and called Atlas (after a character[1] in a popular cartoon at the time), the commercial version was renamed the 1101 because it was designed under "Task 13" (1101 is 13 in binary).
This computer was 38 feet long (11.5 m), 20 feet wide (6 m), and used 2700 vacuum tubes for its logic circuits. Its drum memory was 8.5 inches in diameter (21.6 cm), rotated at 3500 rpm, had 200 read-write heads, and held 16,384 24-bit words (a memory size equivalent to 48 KB).
Instructions were 24 bits long, with 6 bits for the opcode, 4 bits for the "skip" value (telling how many memory locations to skip to get to the next instruction in program sequence), and 14 bits for the memory address. Numbers were binary with negative values in one's complement.The single 48-bit accumulator was fundamentally subtractive, addition being carried out by subtracting the one's complement of the number to be added. This may appear rather strange, but the subtractive adder reduces the chance of getting negative zero in normal operations.
Engineering Research Associates built two Atlas systems for the Navy's Bureau of Ships, installing them in December 1950 and March 1953. There was talk of naming the commercial version MABEL, but Jack Hill suggested 1101 instead. The ERA 1101 was publicly announced in December 1951Events January events January 9 United Nations headquarters officially opens ( New York City). January 15 Ilse Koch, The "Witch of Buchenwald," wife of the commandant of the Buchenwald concentration camp, is sentenced to life imprisonment in a court in We.
Engineering Research Associates built a third machine for their own offices, with the intention of creating a service for other companies needing computing resources. However this failed and in November 1954Events January events January 14 The Hudson Motor Car Company merges with Nash-Kelvinator forming the American Motors Corporation January 14 Marilyn Monroe weds Joe DiMaggio. January 15 Mau Mau leader Waruhiu Itote is captured in Kenya January 20 The Nati Remington Rand donated the machine to Georgia Tech for a claimed value of $500,000. In November 1958Events January January 1 Treaty of Rome founding the EU is implemented January 4 Sputnik 1 falls to Earth from its orbit (launched on October 4 1957) January 8 14 year old Bobby Fischer wins the United States Chess Championship January 18 Armed Lumbee Nat Georgia Tech upgraded this machine with 4096 words of core memory for a cost of $39,400. This 1101 was still running student jobs in 19611961 (As MAD Magazine pointed out on its first cover for the year) was the first "upside-down" year i. one that looked the same upside down since 1881, and the last until 6009. Events January January 1 The farthing coin, used since the 13th century, cease.