% 1 - ορισμός. Τι είναι το Intel 486
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Τι (ποιος) είναι Intel 486 - ορισμός

FAMILY OF 32-BIT MICROPROCESSORS INTRODUCED IN 1989, INCLUDING DX, SX AND SL MODELS
Intel 80486DX; 80486; Intel 486; Intel I486; 486 DX; 486DX; 80486DX; 80486SX; 486 processor; 486dx; Intel i486; Intel 80486 (microarchitecture); Intel i486 (Processor); 486 (PC); 486 (Intel); 486 (computing); 486 (computer); 80-486; SL-enhanced 486; I80486; 486 (CPU); Intel 80486; I486DX
  • The 486DX2 architecture
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  • first 486 system from the UK]] on the cover of BYTE, September 1989
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  • STMicroelectronics' ST ST486DX2-40
  • [[UMC Green CPU]] U5SX
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Intel 486         
<processor> (Or "i486", "iAPX 80486", and "Intel DX4" but usually just "486"). A range of Intel CISC microprocessors which is part of the Intel 80x86 family of processors. The 486s are very similar to their immediate predecessor, the Intel 80386DX. The main differences are that the 486 has an optimised instruction set, has an on-chip unified instruction and data cache, an optional on-chip floating-point unit (FPU), and an enhanced {bus interface unit}. These improvements yield a rough doubling in performance over an Intel 80386 at the same clock rate. There are several suffixes and variants including: Intel 486SX - a 486DX with its FPU disabled (see crippleware). Intel 486DX - 486SX with a working FPU. 486DX-2 - runs at twice the external clock rate. 486SX-2 - runs at twice the external clock rate. 486SL - 486DX with power conservation circuitry. 486SL-NM - 486SX with power conservation circuitry; SL enhanced suffix, denotes a 486 with special power conservation circuitry similar to that in the 486SL processors. 487 - 486DX with a slightly different pinout for use in 486SX systems. OverDrive - 486DX-2 with a slightly different pinout for use in 486SX systems. RapidCAD - 486DX in a special package with a companion FPU dummy package for use in Intel 80386 systems. Intel DX4, Cyrix Cy486SLC. External clock rates include 16MHz, 20MHz, 25MHz, 33MHz, 40MHz, although 16Mhz is rare now, and the 20MHz processors are often clock doubled. The 486 processor has been licensed or reverse engineered by other companies such as IBM, AMD, Cyrix, and {Chips & Technologies}. Some are almost exact duplicates in specications and performance, some aren't. The successor to the 486 is the Pentium. (1995-02-21)
80486         
i486         

Βικιπαίδεια

I486

The Intel 486, officially named i486 and also known as 80486, is a microprocessor. It is a higher-performance follow-up to the Intel 386. The i486 was introduced in 1989. It represents the fourth generation of binary compatible CPUs following the 8086 of 1978, the Intel 80286 of 1982, and 1985's i386.

It was the first tightly-pipelined x86 design as well as the first x86 chip to include more than one million transistors. It offered a large on-chip cache and an integrated floating-point unit.

A typical 50 MHz i486 executes around 40 million instructions per second (MIPS), reaching 50 MIPS peak performance. It is approximately twice as fast as the i386 or i286 per clock cycle. The i486's improved performance is thanks to its five-stage pipeline with all stages bound to a single cycle. The enhanced FPU unit on the chip was significantly faster than the i387 FPU per cycle. The intel 80387 FPU ("i387") was a separate, optional math coprocessor that was installed in a motherboard socket alongside the i386.

The i486 was succeeded by the original Pentium.