Intel celebrates 25 years of Intel Architecture products and one billion chips
Posted on 11-Jun-2003 03:28
Filed under: News
When Intel introduced the first x86 CPU (central processing unit) some 25 years ago, a handheld was a transistor radio, computers were big immobile machines, and the Internet was used by a few of research scientists.
Based on combined desktop, laptop and server shipment data from industry analyst firm Mercury Research*, Intel has shipped over one billion x86 CPUs as of April 2003, roughly 25 years after the debut of the first 8086 microprocessor on June 8, 1978.
Intel is celebrating the 25th anniversary of a processing architecture that has spawned an industry: the Intel® architecture (or x86). It all began with the 8086 CPU, which was the logical evolution of Intel's processor family to 16-bits, and a follow on to the successful 8080 and 8085 chips. Intel's goal at the time was to retain backward compatibility with the large installed base of 8-bit code, while providing a greater address space (a full 1MB!) and faster clock speeds of up to 5 MHz.
The Intel® i286™ chip broke through the 1MB limit on addressable memory. It managed this trick by switching into a new "protected" mode, which offered memory protection between concurrently running software programs, a mainframe-like feature now implemented at the microprocessor level. The i286 also featured built-in privilege levels, allowing for easier development of true multiuser operating systems, such as Xenix*.
While the protected mode had some benefits, they were largely too specific and complex for operating systems to fully utilize them. Thus, the advent of the i386 processor was the inaugural point of the second wave in PC computing. This chip was 32-bits through and through and featured enhanced memory management with variable segment sizes up to 4G, memory paging and virtual memory, which made it ideal for both OS and application developers.
In particular, its inclusion of "flat" mode, where segmentation was essentially bypassed, and "real" mode for backward compatibility to DOS, were particularly powerful and enabled a backward-compatible DOS mode while enabling a forward evolutionary path for Microsoft* Windows* to migrate to full 32-bit operation.
The i486™ processors that followed bumped up the clock speed, moved to a five-stage pipeline architecture, and integrated an instruction and data cache. They also integrated the floating-point unit, which in previous generations was performed by a separate numeric coprocessor.
The Intel® Pentium® processor, which shipped in 1993, represented a fairly significant departure from the i386 generation, and a setback to those RISC proponents who were pointing to the limitations of CISC and the imminent death of the Intel architecture, according to Gelsinger. Most notably, it began a series of extensive innovations that boosted throughput by techniques in addition to revving the clock. It was Intel's first desktop superscalar chip, meaning it could execute more than one instruction at a time.
The immediate next Pentium processor version integrated the MMX™ instruction set, which evolved into a powerful capability to perform a single instruction across multiple data items (SIMD). This was combined with the CD-ROM to create the multimedia PC. Today, the MMX technology is evident in SSE-2 (streaming SIMD extensions), which is the engine that helps make Intel Pentium 4 processors excel with multimedia and imaging applications.