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IBM 1620 data processing machine with IBM 1627 plotter, on display at the 1962 Seattle World's Fair. The IBM 1620 was a model of scientific minicomputer produced by IBM.It was announced on October 21, 1959, [1] and was then marketed as an inexpensive scientific computer. [2]
For example, each address in the IBM 1620's magnetic-core memory identified a single six bit binary-coded decimal digit, consisting of a parity bit, flag bit and four numerical bits. The 1620 used 5-digit decimal addresses, so in theory the highest possible address was 99,999.
The IBM 1620, the Data General Nova, the HP 2100 series, and the NAR 2 each have such a multi-level memory indirect, and could enter such an infinite address calculation loop. The memory indirect addressing mode on the Nova influenced the invention of indirect threaded code .
Early computers that were exclusively decimal include the ENIAC, IBM NORC, IBM 650, IBM 1620, IBM 7070, UNIVAC Solid State 80.In these machines, the basic unit of data was the decimal digit, encoded in one of several schemes, including binary-coded decimal (BCD), bi-quinary and two-out-of-five code.
In computer hardware, a word mark or flag is a bit in each memory location on some early variable word length computers (e.g., IBM 1401, 1410, 1620) used to mark the end of a word. [1] Sometimes the actual bit used as a word mark on a given machine is not called word mark , but has a different name (e.g., flag on the IBM 1620, because on this ...
IBM 1620. A transistor computer, now often called a second-generation computer, [1] is a computer which uses discrete transistors instead of vacuum tubes.The first generation of electronic computers used vacuum tubes, which generated large amounts of heat, were bulky and unreliable.
"One method of designing a slave memory for instructions is as follows. Suppose that the main memory has 64 K words (where K = 1024) and, therefore, 16 address bits, and that the slave memory has 32 words and, therefore, 5 address bits." [48] IBM 1620 CPU Model 1 (a decimal machine) System Reference Library, dated 19 July 1965, states:
System/360 Model 91 front panel IBM 1620 front panel Altair 8800 microcomputer front panel A CDC 6600 system console, a reaction [clarification needed] to the "blinkenlights" front panel. A front panel was used on early electronic computers to display and allow the alteration of the state of the machine's internal registers and memory.