what is the history of microprocessor 80486?

Answer 1

http://en.wikipedia.org/wiki/Intel_80486

The Intel i486 (also called 486 or 80486) is a range of 32-bit scalar Intel CISC microprocessors which is part of the Intel x86 family of processors. The i486's predecessor was the Intel 80386 processor. The first line of 486 processors was introduced in 1989 containing 1.2 million transistors (0.8 micron technology). The i486 was so named without the usual 80-prefix, because of a court ruling that prohibited trademarking numbers (like 80486). Intel dropped number-based naming altogether with the successor to the i486 – the Pentium processor.

From a software point of view, the instruction set of the i486 family is very similar to its predecessor, the Intel 80386, with the addition of only a few extra instructions.

From a hardware point of view, however, the architecture of the i486 is a vast improvement. It has an on-chip unified instruction and data cache, an optional on-chip floating-point unit (FPU) (DX models only), and an enhanced bus interface unit. In addition, under optimal conditions, the processor core can sustain an execution rate of one instruction per clock cycle. These improvements yield a rough doubling in performance over an Intel 80386 at the same clock rate. However, some low-end i486 models were actually slower than the highest-speed 386s, especially so with the 'SX' i486s.

Answer 2

why finding at such previous procs? only involved in heritage or is this for a classification? 286 i think of replaced into first with 24-bit handle. and prolonged mode programming, so all of us got here out with DOS extenders like Phar Lap (which I quite have). FPU replaced into separate as familiar. 386 had 32-bit handle and registers, and presented VM86 and guarded mode programming i think of, and ring 0 (replaced into replaced into ring 0 in 286?). yet FPU replaced into separate as familiar (387). 486 had greater instructions,FPU replaced into separate as familiar. 586/pentium i think of the FPU replaced into merged into the processor. greater instructions extra. greater modes in all hazard. nonetheless 32-bit. 686/pentium professional utilized in servers specifically and replaced into costly. nonetheless 32-bit. it wasn't until eventually the Pentium 4 with the PAE which you acquire previous 32-bit addresses. wasn't quite sixty 4-bit addresses, yet is inching there. in the present day's Xeon E5/E7 processors handle approximately 1TiB,no longer complete 18EB i think of.