X86 is the name applied to a family of computer chips originally developed by Intel.
The first X86 was called the 8086 which was a 16 bit microprocessor released by Intel in the late 70's. It was derived from an earlier 8 bit microprocessor called the 8080. The first PC used a modified 8086 which could use 8 bit peripheral chips called the 8088. Later family members for the 8086 included the 80186, 80286, 80386, 80486. It was this sequence of numbering that the name X86 is derived from. Later Intel adopted names for their chip packages as the numbers could not be copyrighted and they felt that competition using the same name was confusing the marketplace so when the 80586 was released it was call the Pentium. (AMD continued using numbers with a AM5x86 and a Nx686 which were later renamed K5 and K6.) While the names continue to change and the processors keep getting more powerful there is a family resemblance in that the original instruction set was, for the most part, carried forward into the later processors, with new instructions added on to the existing set.
Initially Intel was the only producer of the X86 processors but today there are 3 companies producing these chips; Intel, Advanced Micro Devices (AMD), and VIA Technologies (from Taiwan). The US government requires a backup manufacturer on products they buy.
The X86 is called a CISC, Complex Instruction Set Computer, due to the nature of its instruction set which had varying length commands and could require a variable number of clock cycles to execute each command. This name was applied retroactively after the RISC, Reduced Instruction Set Computers became more common place. The dominant RISC machine is ARM based.
The first X86 processor to support 32 bit instructions was the 80386. For compatibility with existing programs it could use either 16 bit programs or 32 bit programs and was designed to permit more memory addressing and more powerful graphics and multitasking based operating systems. While it was Windows based it had built in support in the OS to even emulate the older DOS operating system to permit the original X86 programs to continue to work. Later hardware used micro-coded processors to support some operations instead of a pure hardware approach.
The X86 of today can be either a 32 bit computer or a 64 bit computer which has to do with its memory addressing capability. To distinguish the two types the 64 bit computer is often called an X64 (or AMD64 since the specification was originally developed by AMD for their K8 processor). A 32 bit machine can access up to 4 GB of data (2^32) using all 32 bits while a 64 bit computer can go much higher (2^64) but both may be limited by the number of i/o pins available to a lower number.
However, both types of computers can use the same basic instructions so 32 bit programs can be made to run on a 32 or 64 bit computer. The reverse is not true, a 64 bit program requires a 64 computer to run it. The oldest 16 bit programs could no longer be used with a 64 bit computer but a simulation program such as "D-Fend Reloaded" can be used to run those earlier programs, including full DOS emulation.
Initially a CISC machine consumed more power than RISC machines so the marketplace for large desktops was X86 based while the small portable devices were RISC based. Today there are lower power X86 designs like the Atom processor that allow either computer design to be in portable devices. This means the decision on computer architecture is made from reasons other than power consumption.
Processor numbers for the Intel® Atom™ processor family are categorized by a three-digit numerical sequence. Netbook class Intel® Atom™ processors have an alpha prefix of N, and Intel Atom processors with an alpha prefix of Z indicate the processor is for Mobile Internet Devices (MIDs). A higher number within a processor class or family generally indicates more features. A higher processor number may have more of one feature and less of another.
- Processor Base Frequency: 1.66 GHz L2 Cache 1 MB
- Performance: 2 Cores 4 Threads.
- Instruction Set: 64-bit
- Instruction Set Extensions SSE2, SSE3, SSSE3
- The N stands for netbook class processor.
 Intel Core i
The latest seventh generation core processors are titled i3, i5, and i7 where i7 is the most powerful. The 4 digit model number will start with the generation number which could as low as 2. The first generation had a 3 digit number. A mobile device with likely have a letter suffix, Y for extremely low power or a U for ultra-low power.
 OS for X86
Initially X86 machines ran DOS OS and later Windows. Today there are implementations of MacOS X and Linux that run on the same or similar hardware. OS2 and several flavors of Unix (Linux) are also designed for X86 processors.