中英对照多处理技术.htm

软考英语精典短文每日一练汇总 软考英语精典短文每日一练汇总

      processors because there are many other factors to be taken into 
      consideration，such as resource sharing．<BR><BR>Fig. 2-2 gives a sketch of 
      multiprocessing and uniprocessing．<BR><BR><BR><BR>2．Multiprocessor 
      Types<BR><BR>There are basically four different types of 
      multiprocessors（MP）．See Fig. 2-3一Fig. 2-6．<BR><BR>1）Shared-Nothing 
      MP<BR><BR>A shared-nothing MP has some of the following 
      characteristics：Each processor is a stand-alone machine．Processors share 
      nothing；each one has its own caches，memory and disks．Also，each processor 
      runs a copy of the operating system．Processors can be interconnected by a 
      LAN if they are loosely coupled or interconnected by a switch if they are 
      tightly coupled．Communication between processors is done via a 
      message-passing library．<BR><BR>Example of a shared-nothing MP are in the 
      IBM RS/ 6000 SP range，as well as Tandem，Teradata and most of the massively 
      parallel machines，including Thinking Machines，Intel Touchstone，Ncube and 
      so on．<BR><BR><BR><BR>2）Shared-Disks MP<BR><BR>In a shared-disks MP，each 
      processor has its own caches and memory，but disks are shared．Also，each 
      processor runs a copy of the operating system．Processors are 
      interconnected through a LAN or a switch．Communication between processors 
      may be done via message passing．<BR><BR>Examples of shared-disks MPs are 
      IBM RS /6000s with HACMP and DEC 
      VAX-clusters．[3]<BR><BR><BR><BR>3）Shared-Memory Multiprocessor<BR><BR>In 
      this type of MP，all of the processors are tightly coupled inside the same 
      box with a high-speed bus or a switch between the processors，the I/O 
      subsystem and the memory．Each processor has its own caches，but they share 
      the same global memory，disks and I/O devices．Only one copy of the 
      operating system runs across all of the processors．This means that the 
      operating system itself has to be designed to exploit this type of 
      architecture[4]（it has to be paralleaed）．Note that，as this work is done 
      for the operating system，all single-thread applications that were running 
      on uniprocessors can，in general，run without notable changes on 
      shared-memory MP．[5]<BR><BR>Shared-memory MP is one of the most common 
      multiprocessing implementations for transaction 
      processing．<BR><BR><BR><BR>4）Non Uniform Memory 
      Architectures（NUMA）<BR><BR>Here are some of the characteristics of the 
      NUMA model：<BR><BR>&#8226; Each group of processors（typically four）has a shared 
      local memory．<BR><BR>&#8226; Each group can access all memory from remote groups 
      as a normal address space access．<BR><BR><BR><BR>&#8226; Only one version of the 
      operating system is needed．<BR><BR>&#8226; Communication between groups is done 
      via a high-speed bus or ring．<BR><BR>Fig. 2-6 shows the NUMA 
      Architecture.<BR><BR><BR><BR>3．Symmetric versus Asymmetric Shared-Memory 
      Multiprocessors<BR><BR>In an asymmetric，shared-memory MP，processors are 
      not equal．One processor is designed as the master processor，and the others 
      are slave processors．The master processor is a general-purpose processor 
      which can perform I/O operations as well as computation while running the 
      operating system．Slave processors can only perform computation．On a slave 
      processor，all I/O operations and general kernel requests are routed to the 
      master processor．Utilization of the slave processor might be poor if the 
      master processor does not service slave processor requests efficiently．As 
      an example，I/O-bound jobs may not run efficiently since only the master 
      CPU runs the I/O operations．<BR><BR>In a symmetric shared-memory 
      multiprocessor（SMP），all of the processors are functionally equivalent；they 
      all can perform kernel，I/O and computational operations．The operating 
      system manages a pool of identical processors，any one of which may be used 
      to control any I/O devices or refer to any storage unit．Since all 
      processors are equal，the system can be reconfigured in the event of a 
      processor failure and，following reboot continue to run．Performance can be 
      optimized，and more processors can be 
      used．<BR><BR>1．多处理与单处理<BR><BR>单处理器（UP）能在该处理器内部实现并行性，例如，在同一CPU周期内，定点部件和浮点部件可以运行几条指令。Power、Power2和Power 
      PC体系结构具有非常高的指令级并行性，然而，一次只能处理一个任务。<BR><BR>单处理器的设计有内在的瓶颈，地址和数据总线限制了数据传送一次仅有一个的业务流。程序计数器迫使指令按严格的顺序运行。即使采用更快的处理器和更多的指令并行性使性能得以改善，但是操作始终按严格的顺序进行。而且，在单处理机中，提高处理器速度不能解决全部问题，因为其他因素，如系统总线和存储器也在起作用。<BR><BR>看来增加更多的处理器是提高系统整体性能的良好解决方案。系统中有多个处理器，由于同一时刻能完成不止一个任务而提高了系统的吞吐量。然而性能的提高与处理器的增加并非简单的正比关系，因为还有很多其他因素要考虑，例如资源共享。<BR><BR>单处理器与多处理的结构如图2-2所示。<BR><BR><BR><BR>2．多处理器的类型<BR><BR>多处理器（MP）有4种基本类型，见图2-3 
      ~ 
      图2-6。<BR><BR>1）无共享多处理器<BR><BR>无共享多处理器有以下一些特性：每个处理器都是一个单独的机器，各处理器都不共享；每个处理器都有自己的高速缓存、存储器和磁盘；另外，每个处理器都运行通过复制获得的操作系统。如果这些处理器间的耦合松散，则可用局域网互联；如果它们之间的耦合紧密，则可用交换机互联。处理器间的通信通过消息传送库完成。<BR><BR>IBM 
      RS/6000 SP机型以及Tandem，Teradata和多数大规模并行机，包括Thinking Machines、Intel 
      Touchstone、Ncube等都是无共享多处理器的例子。<BR><BR><BR><BR>2）共享磁盘多处理器<BR><BR>在共享磁盘多处理器中，每个处理器都有自己的高速缓存和内存，但磁盘是共享的。同样，每个处理器也都各自运行通过复制得到的操作系统，各处理器可通过局域网或交换机互联，处理器间的通信通过消息传送实现。<BR><BR>共享磁盘的多处理器的例子是带有HACMP的IBM 
      RS/6000和DEC 
      VAX-clusters。<BR><BR><BR><BR>3）共享内存多处理器<BR><BR>在这种类型的多处理器中，所有的处理器都紧密耦合，并与高速总线或处理器间的交换机、I/O子系统和内存在同一个机箱内。每一处理器都有自己的高速缓存，但它们共享相同的全局存储器、磁盘和I/O设备，仅有一个通过复制获得的操作系统在所有处理器间运行。这就是说，该操作系统本身必须设计得适用于这种结构类型（必须有并行性）。注意，如操作系统做到这一点，则所有在单处理器上运行的单线程应用程序不必做很大的改动，一般即能运行在共享内存多处理器上。<BR><BR>共享内存多处理器是实现事务处理的最通用的多处理器技术之一。<BR><BR><BR><BR>4）非均匀内存结构（NUMA）<BR><BR>NUMA模型的一些特性是：<BR><BR>? 
      每一组处理器（典型数为4）有一本地共享内存；<BR><BR>? 每一组处理器可以从远程组用正常地址空间访问所有内存；<BR><BR>? 
      仅需要一个操作系统；<BR><BR>? 
      组间的通信通过高速总线或环完成。<BR><BR>图2-6说明了这种NUMA结构。<BR><BR><BR><BR>3．对称与非对称共享内存多处理器<BR><BR>在非对称共享内存的多处理器中，各处理器地位不同，一个处理器设计成主处理器，其他则是从处理器。主处理器是一个通用处理器，它在运行操作系统的同时，能实现I/O操作以及计算工作。从处理器只能完成计算工作。对于从处理器，所有的I/O操作和一般的内核请求都转送给主处理器。如果主处理器未能有效地满足从处理器的请求，那么从处理器的利用率就会很低。例如，由于只有主CPU运行I/O操作，受I/O限制的作业运行很可能是低效的。<BR><BR>在对称共享内存多处理器（SMP）中，所有的处理器在功能上是等效的，它们都能完成内核、I/O和计算操作。操作系统管理同一个处理器池，每一个处理器都可以控制任何I/O设备或访问任何存储部件。因为所有的处理器都是一样的，系统可以在一个处理器发生故障时重新进行配置，接着重新引导，继续运行；可以优化性能，并使用更多的处理器。<BR><BR><BR><BR></DIV></TD></TR>
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      <DIV align=center><A class=chinablue title=给他/她留言 
      href="http://po.csai.cn/write_shortmess.asp?func=0&amp;username=fgfgfg" 
      target=_blank>fgfgfg</A><BR><IMG alt=等级3 
      src="中英对照多处理技术_files/top-3.gif"><BR>
      <DIV class=userInfoBox>积分：9467<BR>第三级</DIV>
      <DIV class=userInfoBox>注册时间<BR>2006-8-17</DIV></DIV></TD>
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    vAlign=top align=left height=70>
      <DIV class=TitleInfoBox align=right>发表时间：2006-9-1 14:59:24　　　第1楼</DIV>
      <HR style="MARGIN-TOP: -5px; COLOR: #cccccc" align=center width="100%" 
      noShade SIZE=1>

      <DIV id=cont_right 
      style="WIDTH: 495px">好东东，楼主哪里找的啊？<BR><BR>指点下撒。先谢谢了。</DIV></TD></TR>
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    <TD class=hai vAlign=top align=middle width=83 height=70>
      <DIV align=center><A class=chinablue title=给他/她留言 
      href="http://po.csai.cn/write_shortmess.asp?func=0&amp;username=飘渺少年狂" 
      target=_blank>飘渺少年狂</A><BR><IMG alt=等级3 
      src="中英对照多处理技术_files/top-3.gif"><BR>
      <DIV class=userInfoBox>积分：7396<BR>第三级</DIV>
      <DIV class=userInfoBox>注册时间<BR>2006-8-17</DIV></DIV></TD>
    <TD class=bbsmain style="WORD-BREAK: break-all; WHITE-SPACE: normal" 
    vAlign=top align=left height=70>
      <DIV class=TitleInfoBox align=right>发表时间：2006-9-3 21:46:05　　　第2楼</DIV>
      <HR style="MARGIN-TOP: -5px; COLOR: #cccccc" align=center width="100%" 
      noShade SIZE=1>

      <DIV id=cont_right style="WIDTH: 495px">HOHO，基本上就是要知道词汇咯</DIV></TD></TR>
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    <TD class=hai vAlign=top align=middle width=83 height=70>
      <DIV align=center><A class=chinablue title=给他/她留言 
      href="http://po.csai.cn/write_shortmess.asp?func=0&amp;username=cyd530" 
      target=_blank>cyd530</A><BR><IMG alt=等级1 
      src="中英对照多处理技术_files/top-1.gif"><BR>
      <DIV class=userInfoBox>积分：66<BR>第一级</DIV>
      <DIV class=userInfoBox>注册时间<BR>2006-8-30</DIV></DIV></TD>
    <TD class=bbsmain style="WORD-BREAK: break-all; WHITE-SPACE: normal" 
    vAlign=top align=left height=70>
      <DIV class=TitleInfoBox align=right>发表时间：2006-9-4 9:51:44　　　第3楼</DIV>
      <HR style="MARGIN-TOP: -5px; COLOR: #cccccc" align=center width="100%" 
      noShade SIZE=1>

      <DIV id=cont_right style="WIDTH: 495px">能不能贴一些比较短的，实用一点的啊？</DIV></TD></TR>
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    <TD class=hai vAlign=top align=middle width=83 height=70>
      <DIV align=center><A class=chinablue title=给他/她留言 
      href="http://po.csai.cn/write_shortmess.asp?func=0&amp;username=fuwenqi" 
      target=_blank>fuwenqi</A><BR><IMG alt=等级3 
      src="中英对照多处理技术_files/top-3.gif"><BR>
      <DIV class=userInfoBox>积分：9956<BR>第三级</DIV>
      <DIV class=userInfoBox>注册时间<BR>2006-8-17</DIV></DIV></TD>
    <TD class=bbsmain style="WORD-BREAK: break-all; WHITE-SPACE: normal" 
    vAlign=top align=left height=70>
      <DIV class=TitleInfoBox align=right>发表时间：2006-9-4 17:49:30　　　第4楼</DIV>
      <HR style="MARGIN-TOP: -5px; COLOR: #cccccc" align=center width="100%" 
      noShade SIZE=1>

      <DIV id=cont_right 
      style="WIDTH: 495px">哎，日积月累的过程，长点无所谓啦！<BR><BR>一天看个一二篇就不错啊</DIV></TD></TR>
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    <TD class=hai vAlign=top align=middle width=83 height=70>
      <DIV align=center><A class=chinablue title=给他/她留言 
      href="http://po.csai.cn/write_shortmess.asp?func=0&amp;username=zzcghose2005" 
      target=_blank>zzcghose2005</A><BR><IMG alt=等级1 
      src="中英对照多处理技术_files/top-1.gif"><BR>
      <DIV class=userInfoBox>积分：270<BR>第一级</DIV>
      <DIV class=userInfoBox>注册时间<BR>2006-9-4</DIV></DIV></TD>
    <TD class=bbsmain style="WORD-BREAK: break-all; WHITE-SPACE: normal" 
    vAlign=top align=left height=70>
      <DIV class=TitleInfoBox align=right>发表时间：2006-9-4 18:19:43　　　第5楼</DIV>
      <HR style="MARGIN-TOP: -5px; COLOR: #cccccc" align=center width="100%" 
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      <DIV id=cont_right style="WIDTH: 495px">不错啊，这些知识相信对很多人都有用</DIV></TD></TR>
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    <TD class=hai vAlign=top align=middle width=83 height=70>
      <DIV align=center><A class=chinablue title=给他/她留言 
      href="http://po.csai.cn/write_shortmess.asp?func=0&amp;username=mayaral" 
      target=_blank>mayaral</A><BR><IMG alt=等级1 
      src="中英对照多处理技术_files/top-1.gif"><BR>
      <DIV class=userInfoBox>积分：72<BR>第一级</DIV>
      <DIV class=userInfoBox>注册时间<BR>2006-8-15</DIV></DIV></TD>
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    vAlign=top align=left height=70>
      <DIV class=TitleInfoBox align=right>发表时间：2006-9-5 11:48:27　　　第6楼</DIV>
      <HR style="MARGIN-TOP: -5px; COLOR: #cccccc" align=center width="100%" 
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      <DIV id=cont_right 
    style="WIDTH: 495px">都是一些零散的文章，哪有这种文章的集合呀？<BR><BR></DIV></TD></TR>
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    <TD class=hai vAlign=top align=middle width=83 height=70>
      <DIV align=center><A class=chinablue title=给他/她留言 
      href="http://po.csai.cn/write_shortmess.asp?func=0&amp;username=zhyaner" 
      target=_blank>zhyaner</A><BR><IMG alt=等级1 
      src="中英对照多处理技术_files/top-1.gif"><BR>