第五章计算机组成.ppt

The arithmetic logic unit(ALU) performs Arithmetic Operation; Logic Operation. Registers are fast stand-alone storage locations that hold data temporarily. Controlling is achieved through wires that can be on or off. Two types of memory : RAM and ROM. RAM(random access memory): (1)RAM can be read from and written to by the user. (2)RAM is volatile. SRAM(static RAM):flip-flop gates, no need for refreshing. DRAM(dynamic RAM):capacitor.need to be refreshed periodically. ROM:(Read-only memory) (1)The user is allowed to read but not write to ROM. (2)ROM is nonvolatile. PROM: EPROM: EEPROM: Input/Output devices can be divided into two broad categories:nonstorage and storage devices. Nonstorage devices allow the CPU/memory to communicate with the outside world but they can not store information. Storage devices, although classified as I/O devices, can store large amounts of information to be retrieved at a later time. We categorize them as either magnetic or optical. Magnetic Storage Devices CD-ROM CD-R CD-RW DVD Controllers or interface:can be a serial or parallel device. A serial controller has only one wire connection to the device. A parallel controller has several connections to the device so that several bits can be transferred at a time. The strategy behind CISC (complex instruction set computer) architecture is to have a large set of instructions, including the complex ones. The strategy behind RISC (reduced instruction set computer) architecture is to have a small set of instructions that do minimum number of simple operations. 指令(instruction) 控制计算机执行特定的算术、逻辑或控制运算的命令。 一条指令可以分两部分：操作码(op code) 和地址码(operands). 0110 000010 000001 ADD REG2 REG1 CPU可以执行的全部指令称为Instruction set(指令集). Key terms CISC(complex instruction set computer)：复杂指令集计算机。 RISC(reduced instruction set computer)：精简指令集计算机。 Key terms address bus(地址总线) address space(地址空间) arithmetic logic unit(算术逻辑单元，ALU) bit pattern(位模式) cache memory(高速缓冲存储器) central processing unit(中央处理单元，CPU) Com