The next generation of computer systems saw the use of
large scale integration (LSI -- 1000 devices per chip) and
very large scale integration (VLSI -- 100,000 devices per
chip)
in the construction of computing elements. At this scale
entire processors will fit onto a single chip, and for simple
systems the entire computer (processor, main memory, and
I/O controllers) can fit on one chip. Gate delays dropped to
about 1ns per gate.
Semiconductor memories replaced core memories as the main memory in most systems; until this time the use of semiconductor memory in most systems was limited to registers and cache. During this period, high speed vector processors, such as the CRAY 1, CRAY X--MP and CYBER 205 dominated the high performance computing scene. Computers with large main memory, such as the CRAY 2, began to emerge. A variety of parallel architectures began to appear; however, during this period the parallel computing efforts were of a mostly experimental nature and most computational science was carried out on vector processors. Microcomputers and workstations were introduced and saw wide use as alternatives to time--shared mainframe computers.
