why 8086(microprocessor) is called so?

Answer 1

It's a tracking number for the type of chip. Other Intel chips at the time were the 8008 and the 8088. Later chips in the series of the 8086 are the 80286, the 80386, the 80486, and the Pentium series.

Answer 2

The 8086 is a 16-bit microprocessor chip designed by Intel in 1978, which gave rise to the x86 architecture. The Intel 8088 (released shortly afterwards) was essentially the same chip, but with an external 8-bit data bus, allowing the use of cheap chipsets. That 8088 processor is notable as the processor used in the original IBM PC.

Both processors were based on the design of the 8080 and 8085 with a similar register set (the 8086 and 8088 were assembly language source-compatible with the 8080), but was expanded to support 16-bit processing. The Bus Interface Unit fed the instruction stream to the Execution Unit through a 6 byte prefetch queue, so fetch and execution were concurrent – a form of loosely coupled pipelining (8086 instructions varied from 1 to 6 bytes).

Buses:

* Address Bus - 20-bit address bus. Can access 220 memory locations i.e 1 MB of memory.
* Data Bus - 16 bit data bus. Can access 16 bit data in one operation. Hence called 16-bit microprocessor.
* Control buses - Carries the essential signals for various operations.

It featured four 16-bit general registers, which could also be accessed as eight 8-bit registers, and four 16-bit index registers (including the stack pointer). The data registers were often used implicitly by instructions, complicating register allocation for temporary values. It featured 64K 8-bit I/O (or 32K 16 bit) ports and fixed vectored interrupts. Most instructions could only access one memory location, so one operand had to be a register. The result was stored in one of the operands.

There were also four segment registers that could be set from index registers. The segment registers allowed the CPU to access one megabyte + 64 KB - 16 bytes of memory in an odd way. Rather than just supplying missing bytes, as in most segmented processors, the 8086 shifted the segment register left 4 bits and added it to the address. As a result segments overlapped, which most people consider to have been poor design. Although this was largely acceptable (and even useful) for assembly language, where control of the segments was complete, it caused confusion in languages which make heavy use of pointers (such as C). It made efficient representation of pointers difficult, and made it possible to have up to 4096 pointers with different values pointing to the same location. Worse, this scheme made expanding the address space to more than one megabyte + 64 KB - 16 bytes difficult. Effectively, it was expanded by changing the addressing scheme in the 80286.

The processor runs at clock speeds between 4.77 (as with the 8088 version used in the original IBM PC) and 10 MHz.

Answer 3

Just the model number Intel assigned to the part. Their first commerical micro chip was assigned a 4004 part number and later designs played on that starting number. Engineers like to name things with numbers. Later Intel was overun with marketing people and started naming the new designs with words, Pentium, etc. A rose by any name would smell as sweet...

Answer 4

Because it came after the 8085. No joking. The 8008 and 8080 had been around for a while and Zilog had the Z-80 and was making a dent in Intel's business.

Answer 5

To be called =D

Answer 6

I believe this might have been the first Pentium.

Answer 7

because they already have the 8080 also due to lake of numbers. :P

Answer 8

mini computer. and microcontroller is called computer on a chip.