第六次作业

第一部分-简答

1. According to the von Neumann architecture, List basic parts of a computer.
   输入设备、输出设备、控制器、存储器、运算器。

2. A computer has 64 MB (megabytes) of memory. How many bits are needed to address any single byte in memory?
   需要16位地址

3. List basic parts of a CPU, include cache or not?
   CPU中也有cache，用来加快运算速度。

4. What mean secondary storage. List some on your PC.
   二级存储是计算机主存储器或内存之外的所有可访问数据存储器。比如硬盘、CD、DVD等。

第二部分-解释名词

1. CPU
   A central processing unit (CPU) is the electronic circuitry within a computer that carries out the instructions of a computer program by performing the basic arithmetic, logical, control and input/output (I/O) operations specified by the instructions. The computer industry has used the term “central processing unit” at least since the early 1960s.Traditionally, the term “CPU” refers to a processor, more specifically to its processing unit and control unit (CU), distinguishing these core elements of a computer from external components such as main memory and I/O circuitry.

2. RAM
   Random-access memory (RAM /ræm/) is a form of computer data storage that stores data and machine code currently being used. A random-access memory device allows data items to be read or written in almost the same amount of time irrespective of the physical location of data inside the memory. In contrast, with other direct-access data storage media such as hard disks, CD-RWs, DVD-RWs and the older magnetic tapes and drum memory, the time required to read and write data items varies significantly depending on their physical locations on the recording medium, due to mechanical limitations such as media rotation speeds and arm movement.

3. ROM
   Read-only memory (ROM) is a type of non-volatile memory used in computers and other electronic devices. Data stored in ROM can only be modified slowly, with difficulty, or not at all, so it is mainly used to store firmware (software that is closely tied to specific hardware, and unlikely to need frequent updates) or application software in plug-in cartridges.

4. Bus(computing)
   In computer architecture, a bus (a contraction of the Latin omnibus) is a communication system that transfers data between components inside a computer, or between computers. This expression covers all related hardware components (wire, optical fiber, etc.) and software, including communication protocols.

5. Parallel computing
   Parallel computing is a type of computation in which many calculations or the execution of processes are carried out simultaneously. Large problems can often be divided into smaller ones, which can then be solved at the same time. There are several different forms of parallel computing: bit-level, instruction-level, data, and task parallelism. Parallelism has long been employed in high-performance computing, but it’s gaining broader interest due to the physical constraints preventing frequency scaling. As power consumption (and consequently heat generation) by computers has become a concern in recent years, parallel computing has become the dominant paradigm in computer architecture, mainly in the form of multi-core processors.

6. 写一段文字，简单解释“云计算（cloud computing）
   云计算，是一种基于互联网的计算方式，通过这种方式，共享的软硬件资源和信息可以按需求提供给计算机各种终端和其他设备。简单的说，就是不通过本机设备而是通过网络使用服务商的服务器进行计算，这样可以快捷方便的进行依赖网络进行计算。

7. 小孙买了计算机主板，说明书表明“支持双通道DDR3-1333内存， 最大支持16G”
   1）DDR3内存，“3”和“1333”的含义是什么？
   3是指第三代，1333是指默认的工作频率为1333hz.
   2）小孙买8G DDR3-1600的内存能提高性能吗？
   能，工作频率提高了。
   3）小孙买4G*2 DDR3-1333的内存能提高性能吗？
   能，可以组成双通道。
   4）16G需要多少位地址？
   34位地址。
   备注，维基百科（中文）“DDR3 SDRAM”