Integrated Circuits
The first integrated circuits (IC) appeared toward the end of the sixties. They
allowed to realize numerous transistors and relative connections on an
only silicon chip. Their use in computers produced further reductions in price
and size of machines and a meaningful increase in their functionality. The
microprocessor appared in the half of the seventies, when Large Staircases
Integration circuits, (LSI) and then Very Large Staircases integration
circuits, (VLSI), whereimplemented. They contained million of interconnected
transistors, realized on an only silicon chip. The computers of the seventies,
could recognize generally groups of eight states,; that is to say/they could
treat eight binary digits (binary digits or bit) for every cycle. A group of
eight bits constitutes a byte; a byte can assume 28=256 possible configurations
of states ON and OFF (1 or 0). Each of these configurations can represent an
instruction, one part of it or a datum suck as a number, a character or a
graphic symbol. The combination 11010010, can represent for instance a binary
numerical datum or an istruction, as 'compare the content register
with that of a memory cell..A computer that processes
information contemporary groups of 8 bits computer is said an 8 bit
computer. Such designation can refer either is to the word length(basic
unity of processed information) of the microprocessor or, more commonly, to the
number of bits moved with a single operation along the data bus, that is the
path connection long which information travely from or towards the
microprocessor. Therefore, an 8 bit microprocessor has length of word of 8
bits, or of a byte; a bus-data to 8 bits it has 8 lines, therefore it carries
information through the system in contemporary groups of 8 bits. Equally,
a 16 bit computer processes information in contemporary groups of
16 bits and a 32 bit processes a group of 32 bits at each step.
The development of computers able to treat in block combinations of 16, 32 or
64 bits increased the processing speed. The whole of all the combinations of
bits that a computer is able to recognize as instructions, is said instruction
set . Both these characteristics are improving in modern computers.