IA-32, IA-64, x86-64, PPC, and More

<摘自 Sybex.linux.Power.Tools>

IA-32  These CPUs power the vast majority of computers sold from the late 1980s to the present. Intel, AMD, VIA, and Transmeta are selling IA-32 CPUs in 2003, and other companies have sold them in the past. The most popular IA-32 CPUs of late are Intel's Pentium 4, Intel's Celeron, AMD's Athlon, and AMD's Duron. The 32 in IA-32 refers to the fact that these CPUs have 32-bit data busses, meaning that they move data in 32-bit chunks. This 32-bit architecture has been adequate for over a decade, but increases in RAM capacity and new concepts in low-level CPU design make it desirable to retire this venerable CPU line. In 2003, both Intel and AMD are pushing new 64-bit CPUs. Time will tell how successful each is in this endeavor.

Note

Linus Torvalds, the creator of the Linux kernel, now works for Transmeta. Therefore, the Linux kernel includes unusually good support for some Transmeta CPU features. These CPUs are uncommon in desktop systems, though; they're most popular in portable devices.

IA-64  Intel's 64-bit CPU architecture is known as IA-64, and it is being sold under the Itanium name. Itanium is a high-performance 64-bit architecture that's being targeted initially at the high-end workstation and server markets. As such, IA-64 systems tend to be expensive. The IA-64 CPU is capable of running IA-32 programs in a compatibility mode, but performance suffers greatly in this mode, and you can't run IA-64 and IA-32 programs at the same time. Aside from the IA-32 compatibility mode, the IA-64 was intended in part to discard much of the historical baggage that's accumulated with the IA-32 architecture over the years.

x86-64  AMD's 64-bit architecture goes by the name x86-64, with chips sold under the names Opteron and Athlon 64. As the name implies, x86-64 is a 64-bit derivative of the 32-bit x86 (IA-32) architecture. As such, it's a less drastic deviation from IA-32 than is IA-64, and performance when running IA-32 programs doesn't suffer greatly. It's also possible to run x86-64 and IA-32 programs side-by-side, which should make the transition from IA-32 to x86-64 relatively painless.

PowerPC  This CPU (often called PPC) was developed jointly by Motorola, Apple, and IBM as a successor to Motorola's 680x0 CPU series, which were most commonly found in Apple Macintoshes from the 1980s and early 1990s. PPC CPUs are common in more modern Macintoshes, in some IBM workstations, and in a few less mainstream systems, such as the AmigaOne. The PowerPC was originally designed as a 32-bit architecture with little historical baggage, unlike the IA-32 and x86-64 CPUs. A 64-bit version is now available, as well.

Alpha  The 64-bit Alpha CPU was originally developed by Digital Equipment Corporation (DEC), but DEC went out of business and Compaq bought much of DEC, including the rights to the Alpha CPU. With the merger of Compaq and Hewlett-Packard (HP) in 2002, the Alpha CPU now belongs to HP, but it appears that HP intends to let the design die. Alpha CPUs found their way into many high-performance workstations and servers, but they never became a viable competitor to IA-32 or PPC for most consumers.

MIPS  The MIPS CPU line includes both 32- and 64-bit variants. These CPUs are most commonly found in embedded devices, such as dedicated routers, digital cable boxes, digital video

recorders, and video game systems. Some of these devices run Linux; therefore, Linux and MIPS are closely related—but in ways that are not obvious to most people.

SPARC  SPARC and UltraSPARC CPUs are used by Sun in its workstations, which usually run Solaris. Linux can also run on most Sun workstations, so if you want to use an UltraSPARC CPU for a Linux workstation or server, you can.