计算机英语第二版清华第2单元.docVIP

Computer Science in English Designed and Programmed By Jiang Tongqiang Miao Tianshun Teaching Assisted Courseware 1 Computer Science in English Chapter 2: Computer System Organization 2 Chapter 2 I. Pre-reading Questions 1. What is a computer system? Reference Key: A computer system consists of hardware system and software system. The hardware of the computer is usually divided into three major parts or three primary subsystems: the CPU, the memory subsystem, and the I/O subsystem. The software system can be divided into two broad categories: application software and system software.. 3 Chapter 2 I. Pre-reading Questions 2. How many levels of memory hierarchy do you know? Name at least three of them. Reference Key: The memory hierarchy system consists of three levels.They are a cache ,the main memory and the auxiliary memory. 4 Chapter 2 I. Pre-reading Questions 3. Identify the types of data transfer modes. Reference Key: Data transfer has three modes: programmed I/O, interrupts, and direct memory access (DMA). 5 being executed：为分词短评作定语，修饰program, 意思是“由……执行”。 along with： 随同……一起,在这里把program与the program’s data连接起来，让它们同时作store的宾语。 1. The memory subsystem is used to store program being executed by the CPU, along with the program’s data. II. Grammatical Notes to the Text 6 as引导的是时间状语从句。 complexity：复杂性，错综性。其形容词形式的complex：错综的，复杂的。 efficient at doing something：有效率的，有做某事的能力。 在该句中，rather than所连接的两个比较对象是using buses与direct connections between every pair of devices。 2. As the complexity of a computer system increases, it becomes more efficient at using buses rather than direct connections between every pair of devices. II. Grammatical Notes to the Text 7 动词indicate后带了3个由whether 连接的宾语从句；在第一个宾语从句中，由动词不定式或to+被动形式构成的不定式被动语态作表语，有“将来要发生的事情”的含义。在第二个宾语从句中，由现在分词短语作表语。 需要注意的是，whether后边常与or(not)连接。 3. These signals indicate whether data is to be read into or written out of the CPU, whether the CPU is accessing memory or an I/O device, and whether the I/O device or memory is ready to tran