电子信息工程专业英语课件2.ppt

《电子信息工程专业英语教程》 Lesson 3 Microprocessors Terminology micron, data width, MIPS reset tri-state buffer pipelining A brief summary of all Pentium families Terminology micron是“微米(百万分之一米)”的意思，和μm一样。Micron值用于度量相应芯片中的最小线宽。Micron值越小，芯片中集成的晶体管数量就越多。 data width是指算术逻辑单元ALU的字长。8-bit的ALU可以进行两个8-bit 数的加、减、乘等运算，32-bit 的ALU可以对32-bit的数进行操作。外部数据总线的宽度一般和ALU的数据宽度相同，但也有例外。如8088 的ALU 是16-bit，而其外部数据总线为8-bit；而Pentium处理器的ALU 是32-bit，而其外部数据总线为64-bit. MIPS Million Instructions Per Second 每秒百万条指令。MIPS是一个粗略表征微处理器性能的指标。因为现代微处理器的种类繁多、结构各不相同，MIPS 指标所能反映的信息很有限。 Reset 复位 复位是指“使系统状态处于指定的初始值” tri-state buffer 三态缓冲器 A tri-state buffer is a device that allows you to control when an output signal makes it to the bus. When the tri-state buffers control bit is active, the input of the device makes it to the output. When its not active, the output of the device is Z, which is high-impedance or, equivalently, nothing. There is no electrical signal is allowed to pass to the output. A technique where the microprocessor fetches the next instruction before completing execution of the previous instruction, in order to increase processing speed.） 流水线是一种在前一条指令全部执行完之前就开始取下一条指令，以提高处理速度的技术。 A brief summary of all Pentium families Pentium 4 - Introduced in 2000 (1.4-3.4GHz) Latest Pentium architecture started out with a 400MHz system bus and 256KB L2 cache (later increased to 800MHz and 2MB). The first models contained 42 million transistors, used the 0.18 micron process and came in 423-pin and 478-pin PGA packages. Intels first Pentium 4 chipset was the 850 and supported only Rambus memory (RDRAM), but subsequent chipsets switched to DDR SDRAM. Celeron - Introduced in 1998 (266MHz-2.8GHz) Less expensive Pentium chips due to smaller L2 caches. First Celerons had no L2 cache, but 128KB on-die cache was added in 1999. Celerons started out with 66 and 100MHz system buses that migrated to 400MHz. Pentium III - 1999-2001 (500MHz-1.13GHz) The Pentium III added 70 additional instructions to the Pentium