Unit 2 Computer Hardware

bus [bQs] n. 总线

ArithmeticLogic Unit 运算器，运算逻辑部件

circuit[5sE:kit] n. 电路，环形

fundamental[7fQndE5mentEl] adj. 基本的，重要的

maintain[men5tein] vt. 保持，interconnected by buses, often made of groups of wires (See Figure 2.1).

Arithmetic Logic Unit

In computing, an arithmetic logic unit is a digital circuit that performs arithmetic and logical operations. The ALU is a fundamental building block of the central processing unit (CPU) of a computer, and even the simplest microprocessors contain one for purposes such as maintaining timers. The processors found 坚持

accommodate[E5kCmEdeit] vt. 容纳，顺应

classification[7klAsifi5keiFEn]n. 分类，类别

distinct[dis5tiNkt] adj. 截然不同的，明显的

architecture[5B:kitektFE] n.体系结构，建筑学

address[E5dres] n. 住址，地址

binary[5bainEri] n. 二进制

register[5redVistE] n. 寄存器

inside modern CPUs and graphics processing units (GPUs) accommodate very powerful and very complex ALUs; a single component may contain a number of ALUs.

Mathematician John von Neumann proposed the ALU concept in 1945, when he wrote a report on the foundations for a new computer called the EDVAC. Research into ALUs remains an important part of computer science, falling under arithmetic and logic structures in the ACM Computing Classification System.

Control Unit

The control unit (often called a control system or central controller) manages the computer's various components; it reads and interprets the program instructions, transforming them into a series of control signals which activate other parts of the computer. Control systems in advanced computers may change the order of some instructions so as to improve performance. In computers, the control unit was historically defined as one distinct part of the 1946 reference model of Von Neumann architecture. In modern computer designs, the control unit is typically an internal part of the CPU with its overall role and operation unchanged.

Memory

A computer's memory can be viewed as a list of cells into which numbers can be placed or read. Each cell has a numbered “address” and can store a single number. The information stored

in memory may represent practically anything. Letters, numbers, even computer instructions can be placed into memory with equal ease. In almost all modern computers, each memory cell is set up to store binary numbers in groups of eight bits (called a byte).

The CPU contains a special set of memory cells called registers that can be read and written to much more rapidly than

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