Tuesday, March 31, 2009

x86 Rises, Part 1, The Background

Several years ago I drafted a white paper I called "x86 Everywhere". I started it in the fall of 2004, let it sit, and updated it in April 2005. It remains unfinished, but with the release today of Intel's Nehalem processor, I took a look at it again. Here it is:

What is “x86 Everywhere”? x86 Everywhere is a concept that the dominance the x86 instruction set architecture (ISA) currently has on the desktop and entry server markets will expand into the midrange and high-end datacenter server markets, eventually reaching a tipping point, and displacing most RISC/UNIX platforms. Over time the x86 ISA establishes a monopoly in the datacenter similar to its current monopoly on the desktop.

The drivers for such a scenario are purely economic, but this does not refer to server acquisition costs. Instead it refers to the economic advantages a single, dominant ISA would bring to system vendors and independent software vendors. This is not the first time such a scenario has been speculated. In the early and mid 1990s, when Microsoft announced Window NT as a portable, multiplatform operating system for both RISC and x86, many speculated Windows would become the dominant operating system and programming application binary interface (ABI) from the desktop to large datacenter servers. A few years later, many speculated Intel's IA-64 “Merced” (later branded Itanium) ISA would dominate all computers, displacing RISC from the datacenter. Desktop PCs, entry and midrange servers running Microsoft Windows and Novell Netware, and high-end datacenter servers running UNIX would all use the IA-64 architecture. Despite this speculation, few put two and two together and speculated a Windows/IA-64 monopoly platform combination. The latest domination scenario proposed a few years ago was Linux would displace all UNIX variants. In this scenario, system vendors with their own UNIX variants would simply abandon their UNIX distributions and instead port Linux to their RISC architectures. This scenario is amazingly similar to the speculation about Microsoft Windows in the mid 1990s. Then experts suggested RISC vendors would abandon their UNIX variants to instead embrace Windows.

There is a huge difference with x86 Everywhere. The difference is the current installed base of x86 systems, and the current willingness of customers to use x86 systems for critical tasks. This is not to say other ISAs will exist. While RISC/UNIX established dominance in the datacenter in the 1990s, mainframes still exist, and while x86 is dominant on the desktop, the Apple Macintosh continues to be successful as an alternative platform. However, in this scenario, traditional RISC/UNIX systems are rendered to a smaller, niche market.

Three trends could allow what I call "x86 Everywhere" to happen.

I will cover those three trends in my next post.