At present, the server CPU still according to the CPU instruction system to differentiate, usually divides into the CISC type CPU and the RISC type CPU two kinds, later appeared a 64 bit vlim (Very long instruction Word Ultra long instruction set schema) instruction system's CPU.
First, CISC type CPU
CISC is an abbreviation for the English "Complex instruction set Computer", which means "complex instruction set", which refers to a series of CPUs produced by Intel (a naming specification for Intel CPUs) and their compatible CPUs (other vendors such as AMD, Via, etc., which is based on a PC (personal computer) architecture. This CPU is typically a 32-bit structure, so we also turn it into a IA-32 CPU. (Ia:intel Architecture,intel architecture). CISC-type CPU currently has the main Intel server CPU and AMD server CPU two categories.
Two, RISC type CPU
RISC is the abbreviation of "Reduced instruction set Computing" in English, meaning "simplified instruction set" in Chinese. It was developed on the basis of CISC (Complex instruction Set Computer) instruction system, and some people tested the CISC machine to show that the use frequency of various instructions was quite disparity, the most commonly used is some simple instructions, they only accounted for 20% of the total number of instructions, However, the frequency of the program appears to account for 80%. Complicated instruction system will inevitably increase the complexity of the microprocessor, so that the development of the processor time is long and the cost is high. and complex instructions require complex operations that will inevitably degrade the speed of the computer.
For the above reasons, the the 1980s RISC CPU was born, as opposed to the CISC-type CPU, RISC-type CPU not only streamlined the instruction system, but also adopted a kind of called "Superscalar and Super Pipeline structure", Greatly increased parallel processing capability (parallel processing refers to a server with multiple CPUs processing simultaneously.) Parallel processing can greatly improve the data processing capacity of the server. Departmental, enterprise-level servers should support CPU parallel processing technology. In other words, the architecture in the same frequency, the use of RISC architecture CPU than the CISC architecture of the CPU performance is much higher, which is determined by the technical characteristics of the CPU. At present in the high-end server commonly used in this instruction system CPU, especially high-end servers are all using RISC instruction system CPU. RISC instruction system is more suitable for high-end server operating system UNIX, now Linux also belongs to the Unix-like operating system. RISC CPUs are incompatible with the software and hardware of Intel and AMD CPUs.
At present, in the middle-grade server using RISC instruction CPU mainly has the following categories:
(1) PowerPC processor
(2) SPARC Processors
(3) Pa-risc processor
(4) MIPS processor
(5) Alpha processor