计算机英语实用教程Unit 3.doc

司爱侠 张强华 宋德富 张美兰 编著 计算机英语实用教程电子教案Unit 3 Memory【教学目的】 Learn about the English terms of the memory, including IC, memory types, MIPS, chip set, flash memory, memory cycle time, DRAM, SDRAM, registered memory, static Random Access Memory, EEPROM, virtual memory, bandwidth, cache, parity and etc. Improve the students ability to understand the long and difficult sentences in the text. Master the key language points and grammatical structures in the text. consolidate the technical terms and important professional phrase by doing exercises. 【教学重点难点】Important technical terms: chip set(芯片组)，flash memory（闪存），memory cycle time（内存周期时间），registered memory（寄存器内存），static Random Access Memory（静态随机访问存储器），virtual memory（虚拟内存），bandwidth（带宽），cache（高速缓冲存储器），parity（奇偶校验），non-volatile memory （非永久性存储器） Abbreviation: IC, MIPS, DRAM, SDRAM, EEPROM, SDRAM Difficult sentences: 1. A tiny complex of electronic components and their connections that is produced in or on a small slice of material (such as silicon)2. “Dynamic” means the DRAMs need a constant “refresh” (pulse of current through all of the memory cells) to keep the stored information.3. Synchronous dynamic random access memory delivers bursts of data at high speeds using a synchronous interface.4. Registers delay memory information for one clock cycle to ensure all communication from the chipset is collected by the clock edge, providing a controlled delay on heavily loaded memories.5. It is measured from the time that an address and proper control signals are given, until the information is stored or placed in the devices output(s). Review the important points of essential Englishbe referred to as with the exception that in that【教学步骤】Step OneRead and explain Text A to the students and ask the students to keep in mind the following professional terms:1. Chip Set: A number of integrated circuits designed to perform one or more related functions. For example, one chipset may provide the basic functions of a modem while another provides the CPU functions for a computer. Newer chipsets generally include functions provided by two or more older chipsets. In some cases, older chipsets that required two or more physical chips can be replaced with a chipset on one chip. 2. Flash Memory: A special type of EEPROM that can be erased and reprogrammed in blocks instead of one byte at a time. Many modern PCs have their BIOS stored on a flash memory chip so that it can easily be updated if necessary. Such a BIOS is sometimes called a flash BIOS. Flash memory is also popular in modems because it enables the modem manufacturer to support new protocols as they become standardized. Flash memory is also called flash RAM.3. Memory Cycle Time: The time it takes to perform one memory cycle- a series of operations that take place to read or write a byte of memory. For destructive memories, it includes the regeneration of the bits.4. Registered Memory: Registered memory modules have built-in registers on their address and control lines. A register is a very small temporary holding area (usually 64 bits) for data. These registers act as buffers between the CPU and the memory. The use of registered memory increases system reliability, but also slows the system down a very slight bit as data must be moved through the registers. Some systems do not support registered memory, others require registered memory, and many more give you the option to use registered or unregistered memory. The use of registered memory is recommended for server-class systems. It is not useful on gaming systems. Registered memory is also known as buffered memory. Unregistered memory is also known as unbuffered memory.5. SRAM (static RAM): is random access memory (RAM) that retains data bits in its memory as long as power is being supplied. Unlike dynamic RAM (DRAM), which stores bits in cells consisting of a capacitor and a transistor, SRAM does not have to be periodically refreshed. Static RAM provides 6. Virtual Memory: An imaginary memory area supported by some operating systems (for example, Windows but not DOS) in conjunction with the hardware. You can think of virtual memory as an alternate set of memory addresses. Programs use these virtual addresses rather than real addresses to store instructions and data. When the program is actually executed, the virtual addresses are converted into real memory addresses. The purpose of virtual memory is to enlarge the address space, the set of addresses a program can utilize. For example, virtual memory might contain twice as many addresses as main memory. A program using all of virtual memory, therefore, would not be able to fit in main memory all at once. Nevertheless, the computer could execute such a program by copying into main memory those portions of the program needed at any given point during execution. 7. bandwidth: (1) A range within a band of frequencies or wavelengths.(2) The amount of data that can be transmitted in a fixed amount of time. For digital devices, the bandwidth is usually expressed in bits per second (bps) or bytes per second. For analog devices, the bandwidth is expressed in cycles per second, or Hertz (Hz).8. cache: a special high-speed storage mechanism. It can be either a reserved section of main memory or an independent high-speed storage device. Two types of caching are commonly used in personal computers: memory caching and disk caching.9. parity: The quality of being either odd or even. The fact that all numbers have a parity is commonly used in data communications to ensure the validity of data. This is called parity checking. 10. non-volatile memory: Types of memory that retain their contents when power is turned off. ROM is nonvolatile, whereas RAM is volatile. This term often refers to the CMOS memory in PCs that holds the BIOS. Step Two Help the students to remember the following Abbreviation: IC (Integrated circuit) 集成电路MIPS (Millions of instructions per second) 每秒钟的百万指令数DRAM (Dynamic random access memory) 动态访问存储器SDRAM (Synchronous dynamic random access memory) 同步动态随机访问存储器EEPROM (Electrically erasable, programmable, read-only memory) 电可擦除可编程只读存储器Step Three Help the students to analyze the following long difficult sentences: 1) A tiny complex of electronic components and their connections that is produced in or on a small slice of material (such as silicon). 这是解释集成电路（Integrated Circuit）的一句话。句中的complex作为名词的意思是“合成体”：A whole composed of interconnected or interwoven parts由相互关联交织的部分组成的整体。因此a tiny complex of electronic components and their connections应该译成“电子部件和它们连线的微小合成体”；后面定语从句补充说明这个合成体是怎样制成的，即嵌入小片材料里边或固定在小片材料上面（譬如硅片）。2) “Dynamic” means the DRAMs need a constant “refresh” (pulse of current through all of the memory cells) to keep the stored information.这是解释dynamic random access memory(DRAM动态访问存储器)的句子。Refresh是动词“刷新”，“更新”，现把它做名词使用，句子结构很简单为need sth. to do sth. 即DRAM型内存需要不断“刷新”来保持存储的信息；括号中名词短语pulse of current为“电流脉冲”，the memory cells为“存储单元”，连起来为“通过内存单元的电流脉冲（刷新）”。3) Synchronous dynamic random access memory delivers bursts of data at high speeds using a synchronous interface.这是解释SDRAM“同步动态随机访问存储器”中的一句。delivers bursts of data at high speeds是“高速传输突发性数据”；using a synchronous interface为补充说明“使用同步接口”。本句可以改写成类似汉语句式的结构use sth to do sth.：Synchronous dynamic random access memory uses a synchronous interface to deliver bursts of data at high speeds. “同步动态随机访问存储器用同步接口高速度地传输突发性数据”。4) Registers delay memory information for one clock cycle to ensure all communication from the chipset is collected by the clock edge, providing a controlled delay on heavily loaded memories.这是解释Registered Memory中的一句。其中的短语有：memory information内存信息；one clock cycle一个时钟周期；all communication from the chipset 芯片组的所有通讯；the clock edge 时钟端；a controlled delay一个受控的延迟；heavily loaded memories很大的内存压力。不定式to ensure为目的；providing表示结果，这样就可以通过适当的汉语连接词表达其逻辑关系，译成通畅的汉语。全句的参考译文为：寄存器延迟一个时钟周期的内存信息，以保证芯片组的所有通讯通过时钟端得以汇集，这样在内存压力很大的时候提供了一个受控的延迟。5) It is measured from the time that an address and proper control signals are given, until the information is stored or placed in the devices output(s). 这是解释speed中的一句，其前的句子为The time it takes to put information into memory or get information out of memory. “把信息载入内存或从内存得到信息的时间。”接着的这一句解释时间计算的起点和终点is measured from the time后面用一个定语从句具体说明起点为“得到一个地址和适当的控制信号”；终点则用until从句表达“到信息被存储或放到设备输出中”。参考译文为：它是从得到一个地址和适当控制信号作为起始时间计算，直到信息被存储或放到设备输出中。Step FourReview the important idioms of essential English1. be referred to as 主动语态为refer sb. or sth. as这里的refer为“describe描述”义，如：He always refers to the house as his refuge.他总是把这个房子描述成“难民营”/“避难所”。科技英语中常用其被动态，可以译成“被称作”，“被叫作”等，如本文中的Its is actually SDR SDRAM (single data rate SDRAM) but is usually used to referred to as just “SDRAM.” 它实际上是SDR SDRAM（单数据速率SDRAM），但通常就称为DDR。Unit 4的 Text B解释ASCII时有这么一句话：People will often refer to a bare text file without complicated embedded format instructions as an ASCII file,“人们常把不含复杂格式指令的纯文本文件叫作ASCII文件”，这是refer to as 的主动式例句。2. with the exception that “除之外”，that后跟句子表达，实际上是一种否定。例如本课中的句子：An integrated circuit similar to a DRAM (dynamic random access memory) with the exception that the memory does not need to be refreshed. 该存储器（静态随机访问存储器）的集成电路与DRAM（动态访问存储器）类似，但是不需要进行内存刷新。如果后面不是句子，只是一个名词（短语）那就用with the exception of，如：I like all kinds of films with the exception of (= but not) horror films. 我喜欢所有的电影，但恐怖电影除外。3. in that 是一个从属连词，表示原因，相当于because，如：This research is important in that it confirms the link between aggression and alcohol. “这项研究非常重要因为它确认了挑衅行为与酗酒的联系”。本课中的句子：EEPROMs differ from DRAMs in that the memory is saved even if electrical power is lost. “EEPROM类与DRAM类不同，因为即使电源关闭，EEPROM的内容也会保存下来”。Step Five Text B 难句解析1. A hard disk drive (HDD), commonly referred to as a hard drive, hard disk or fixed disk drive, is a non-volatile storage device which stores digitally encoded data on rapidly rotating platters with magnetic surfaces.主语A hard disk drive（硬盘驱动器）后由commonly referred to as引出它的通常的又名：hard drive, hard disk or fixed disk drive（硬盘驱动器，硬盘或固定硬盘驱动器）。谓语部分是系表结构is a non-volatile storage device（是一个非易失的储存设备），后面的定语从句补充说明硬盘驱动器所存储的是数字编码数据，存放在高速旋转的磁盘上。2. A typical HDD design consists of a spindle which holds one or more flat circular disks called platters, onto which the data is recorded.通常的硬盘驱动器包含有一个轴，该轴上承托着一个或多个圆盘，数据就写在圆盘上。3. The flexible, somewhat U-shaped, ribbon cable barely visible below and to the left of the actuator arm is another part of