18-bit
Encyclopedia
18 binary digits have (1000000 octal
, 40000 hexadecimal
) unique combinations.
Octal
The octal numeral system, or oct for short, is the base-8 number system, and uses the digits 0 to 7. Numerals can be made from binary numerals by grouping consecutive binary digits into groups of three...
, 40000 hexadecimal
Hexadecimal
In mathematics and computer science, hexadecimal is a positional numeral system with a radix, or base, of 16. It uses sixteen distinct symbols, most often the symbols 0–9 to represent values zero to nine, and A, B, C, D, E, F to represent values ten to fifteen...
) unique combinations.
Example 18-bit computer architectures
- Possibly the most well-known 18-bit computer architectures are the PDP-1PDP-1The PDP-1 was the first computer in Digital Equipment Corporation's PDP series and was first produced in 1960. It is famous for being the computer most important in the creation of hacker culture at MIT, BBN and elsewhere...
, PDP-4, PDP-7PDP-7The DEC PDP-7 is a minicomputer produced by Digital Equipment Corporation. Introduced in 1965, it was the first to use their Flip-Chip technology. With a cost of only $72,000 USD, it was cheap but powerful by the standards of the time. The PDP-7 was the third of Digital's 18-bit machines, with...
, PDP-9 and PDP-15 minicomputerMinicomputerA minicomputer is a class of multi-user computers that lies in the middle range of the computing spectrum, in between the largest multi-user systems and the smallest single-user systems...
s produced by Digital Equipment CorporationDigital Equipment CorporationDigital Equipment Corporation was a major American company in the computer industry and a leading vendor of computer systems, software and peripherals from the 1960s to the 1990s...
from 1960 to 1975. - UNIVACUNIVACUNIVAC is the name of a business unit and division of the Remington Rand company formed by the 1950 purchase of the Eckert-Mauchly Computer Corporation, founded four years earlier by ENIAC inventors J. Presper Eckert and John Mauchly, and the associated line of computers which continues to this day...
produced a number of 18-bit computers, including the UNIVAC 418UNIVAC 418The UNIVAC 418 was a transistorized, 18-bit word core memory machine made by Sperry Univac. The name came from its 4 microsecond memory cycle time and 18-bit word. The assembly language for this class of computers was TRIM III and ART418....
and several military systems. - The IBM 7700 Data Acquisition SystemIBM 7700 Data Acquisition SystemThe IBM 7700 Data Acquisition System was announced by IBM on December 2, 1963.It was capable of collecting data from as many as 32 sources simultaneously, process the data and transmit results to up to 16 remote printers, display units or plot boards....
was an 18-bit computer. - The BCL MolecularBCL MolecularThe BCL Molecular 18 was a range of 18-bit computers originally manufactured by Systemation Limited and serviced by Business Mechanisation Limited. The two companies merged in 1968 to form Business Computers Limited - a public limited company. Business Computers Ltd subsequently went into...
- The NASA Standard Spacecraft Computer NSSC-1NSSC-1The NASA Standard Spacecraft Computer-1 was a computer developed as a standard component for the MultiMission Modular Spacecraft at the Goddard Space Flight Center in 1974. The basic spacecraft was built of standardized components and modules, for cost reduction. The computer had 18 bits of core...