Dream's profile梦境~~~幻觉PhotosBlogListsMore  |  Tools Help |
梦境~~~幻觉梦中体会一切 感谢访问！
“六度空间”理论“六度空间”理论又称作六度分隔(Six Degrees of Separation)理论。这个理论可以通俗地阐述为：“你和任何一个陌生人之间所间隔的人不会超过六个，也就是说，最多通过六个人你就能够认识任何一个陌生人。”该理论产生于20世纪60年代年代，由一个美国心理学家米尔格伦提出来的。 1998年初，康奈尔大学的两名研究者通过构建社会网络的数学模式---“小世界模型”，解释了六十亿人如何靠着六条“联系”与别人相连，从而开辟了社会网络研究的源头。 对于这个理论，我并没有通过数学模型那么复杂的方法去验证。我用了一种较为粗略的方法：既然两个人之间由六个人介绍，那么他们一定是通过了七次介绍，现在世界人口是65亿，我对65亿开七次方根，结果是25.2257，我们就算26个，那么如果满足六度空间的结论，每个人至少和社会中的26个人有联系----至少是可以介绍的那种。 26个联系，我觉得是个非常保守的数字：学校里每个班的学生就有50多个，一个人的亲属也有20多个，再加上同事，100个应该是有的。所以六度空间的结论是值得相信的。 而如果按照26个联系去计算，五度空间可以覆盖的人群大约是3亿，四度空间是1千万。日本人口约为1.3亿，所以两个日本人之间只需要5个人去介绍，成都人口是1千万，两个成都人之间只需要4个人去介绍。 上面的推断也许不够科学和严谨，其中可能发生重复的情形没有考虑进去，但我觉得这对理解六度空间来说，已经足够了。 我觉得六度空间理论是哲学中普遍联系理论极好的注解。上学时，哲学课中有个物质之间存在普遍联系的规律，那时老师讲了很多例子，大家还是感觉很懵懂，如果有六度空间理论去佐证，那就容易理解多了；当然，六度空间的结论和社会中人和人之间的普遍联系是分不开的，没有最起码的26个联系人，六度空间的结果是不可能存在。 六度空间的结论也说明指数运算是一种可怕的运算，因为在7和26的各种运算中，只有指数运算能超过65亿，而乘法的结果还不到200。学过计算机语言大多知道有个汉诺塔问题，也能证明指数的可怕： 汉诺塔问题是一道典型递归调用，但谁也不敢把层数设计为64，因为运行的时间太长，如果无法退出，电脑将会死机。这个问题的结果约是2的64次方，如果每次移动移动需要1秒，移完这些金片需要5800多亿年，比地球寿命还长，当前最快的计算机也不能模拟64层的汉诺塔。类似的故事还有舍罕王用棋盘奖励宰相粮食的传说，当然，结果同样是大的可怕的天文数字-----国王奖励给宰相的粮食超过人类世界两千年农业产量。 指数运算的确是一种可怕的运算，人们习以为常的几十个经常联系的人，通过指数运算的7次推演居然能联系到世界上的每一个人，形成了这个这个既让人吃惊而又不得不信服的“六度空间”理论 通过正版windows验证的四种方法WINDOWS XP自动在线升级不能进行了，因为通不过正版windows验证。没办法，搜索网站，从这个网站发现了三种方法： １。教你通过windows的正版验证(不改一字,只打个勾) ２。由于现在微软开始实行“Windows 正版增值计划”，需要验证您的 Windows 软件是否为正版，否则不能下载更新及一些增值软件。（部分VOL大客户版也不行）到http://www.microsoft.com/resources/howtotell/zh-chs/windows/default.mspx网站进入验证，下载并安装正版验证补丁，进入验证。如果你验证通过就下载恭喜你不用继续以下部分了。否则打开C:\Documents and Settings\All Users\Application Data\Windows Genuine Advantage\data文件夹，删除原来的data.dat文件，再新建一个文本文件，内容任意（不写任何字也可以），将其保存为data.dat(注意扩展名）。并修改这个dat文件为只读属性（关键）。通过Update网站、正版特别提供网站及下载中心站点正版下载的检验，都PASS。 ３。如果上面两种方法都无效，那就利用这个CDKEY来通过验证！ 点击下载此文件 ４。更绝的办法就是从９down.com 那里得到的，全文如下： Instructions: 我亲自试过了，第一种方法没有通过。用的第二种方法通过的。不过，第三种方法绝对能通过。第四种方法大家可一试。天才想法！ 本文转自：http://www.paimm.com/blog/user1/1/archives/2006/824.shtml 作者：bioguider 发表于 2006-5-21 19:37:14 [转]把“女友”升级为“老婆”的时候发生的bug 亲爱的技术支持： 我急需您的帮助。我最近将“女朋友7.0”升级到“妻子1.0”，发现这个新程序意外地启动了孩子生产程序，而且占用了大量的空间和珍贵的资源。这在产品的使用手册中没有提到。此外“妻子1.0”自动将自己安装到其他的所有的程序中，它随系统同时启动，监控整个系统的状态。男人夜出2.5”和“高尔夫5.3”无法再运行，一旦运行该程序系统即行崩溃。试图运行“周日足球6.3”经常失败，而“周六购物7.1”却代之运行。看来我无法保留“妻子1.0”，因为它和我喜欢运行的任何程序都不相容。我打算回到“女朋友7.0”，可是这个程序又无法卸载。 请您帮帮我吧！ 乔 给乔的回信: 亲爱的乔： 这是个很普通的问题，产生于你对基本原理的不了解。 很多的男人将“女朋友7.0”升级到“妻子1.0”，以为“妻子1.0”是一个“实用与娱乐程序”。然而“妻子1.0”却是个操作系统，是被设计用来运行所有程序的。你不可能清除“妻子1.0”，也不可能回到“女朋友7.0”，因为“妻子1.0”的设计中不具有这个功能，无论是卸载、删除或是清除已经安装在系统中的这些程序文件，都是不可能的。 有些人曾试图安装“女朋友8.0”或者“妻子2.0”，结果是产生了更多的问题(参见手册中的赡养费/孩子的养育/律师费用)。我安装过“妻子1.0”，我建议你保持现在的安装状态，妥善解决遇到的困难。 当任何错误或问题出现的时候，不论你认为是什么原因引起的，你必须运行“C:＼我道歉”程序，并且避免使用“退出键”。必要时可能需要运行“C：＼我道歉”多次，希望最终能使*作系统恢复到初始状态。 “妻子1.0”虽然是一个需要高保养的程序，但同时对人可能是非常有益的。充分地利用它，需要买些额外的软件比如“鲜花2.0”和“巧克力5.0”。 不要在任何情况下安装“秘书(短裙版)”，因为“妻子1.0”不支持这种程序，而且系统多数时候肯定会崩溃 本文章转自www.pconline.com.cn论坛 作者:萨顶顶 HK 归来玩的很high～～～～～
好开心的度过了3天假期，enjoy～～～～
CCNA-4- Version 2 - ======================================================================================================== Refer to the exhibit. How many broadcast domains are shown? *Three ==================================================== When using Category 5 UTP cable, which RJ-45 pin pairs are used to exchange data between hosts on an Ethernet network? *1 and 2; 3 and 6 ==================================================== Refer to the exhibit. A network administrator has configuredF a network after subnetting the network number 192.168.0.0/28. Workstation 1 is not able to communicate with Workstation 2. What is the cause of this loss in communications? *Workstation 1 is not on the same network that the Router 1 LAN interface is on. ==================================================== Refer to the exhibit. The hub and the switch are operating using factory default settings. Which hosts will receive the frame if host A transmits a broadcast frame? *Workstations B, C, D, E, and the router will receive the data. ==================================================== Refer to the exhibit. A network associate needs to establish an Ethernet connection between Host A and Host B. However, the distance between the two hosts is further than the cabling standards allow. Which two devices that operate at the physical layer of the OSI can be used to allow Host A and Host B to communicate? (Choose two.) *hub *repeater ==================================================== Refer to the exhibit. A network technician is trying to determine the correct IP address configuration for Host A. What is a valid configuration for Host A? IP address: 192.168.100.20; Subnet Mask: 255.255.255.240; Default Gateway: 192.168.100.17 ==================================================== Which devices will create multiple collision domains in an Ethernet network? (Choose two.) *switch *router ==================================================== Refer to the exhibit. What is the order of the TCP/IP Protocol Data Units as data is moved as indicated through the OSI model? *bits, frames, packets, segments, data ==================================================== Refer to the exhibit. The connections in the exhibit are labeled A through E. Which of these indicate LAN links? (Choose two.) *link A *link E ==================================================== Refer to the exhibit. Which type of UTP cable should be used to connect Host A to Switch1? *straight-through ==================================================== ｂａｓｅd on the graphic above, which of the following occurs as each host system comes on line in the topology? *The switch adds MAC address to the bridge table as each host sends a frame. ==================================================== How does a switch learn the addresses of hosts connected to its ports? *The switch reads the source MAC address on incoming frames and records it in CAM. ==================================================== Refer to the exhibit. Which diagram represents the network topology that an administrator would prefer, and why would the administrator prefer it? *Diagram A. It will better provide available bandwidth to the hosts. ==================================================== After an unsuccessful ping to the local router, the technician decides to investigate the router. The technician observes that the lights and fan on the router are not operational. In which layer of the OSI model is the problem most likely occurring? *physical ==================================================== A user initiates three simultaneous FTP connections from the local host to the same FTP server. Which OSI layer is responsible for establishing and managing these different FTP connections? *session ==================================================== Which technologies are considered to be LAN technologies? (Choose two.) *Token Ring *Ethernet ==================================================== A router interface has been assigned an IP address of 172.16.192.166 with a mask of 255.255.255.248. To which subnet does the IP address belong? *172.16.192.160 ==================================================== What is the correct number of usable subnetworks and hosts for the IP network address 192.168.35.0 subnetted with a /28 mask? *14 networks / 14 hosts ==================================================== In the exhibit, the connections between the devices are labeled A, B, C, D, and E. For each connection, what is the correct UTP cable to use? *A=rollover, B=straight, C=straight, D=crossover, E=crossover ==================================================== A network administrator has added a new switch to the network. The new switch connects to an existing switch that is already installed. Which UTP cable correctly connects the new switch to the existing switch? *crossover ==================================================== Refer to the exhibit. What must be configured on Host B to allow it to communicate with the file server? (Choose three.) *a unique host IP address *the subnet mask for the LAN *the default gateway address ==================================================== Refer to the exhibit. Host A pings Host B. What can be concluded about the source and destination addresses contained in the communication sent by Router R5 when it forwards the ping out the Ethernet interface to Host B? (Choose two.) *source MAC address: 5555.AAAA.6666 *destination IP address: 192.168.10.134 ==================================================== What is the decimal representation of the binary number 11111000? *248 ==================================================== A large company has a network that is constantly changing. The routing tables in the routers need to be adjusted to reflect the changes in the routing paths. What type of routing would the network administrator implement? *dynamic routing protocols ==================================================== Which network device creates the highest amount of latency? *router ==================================================== Why do vendors utilize the OSI model when designing networking products? *It ensures greater compatibility and interoperability with equipment from different vendors. ==================================================== Which type of address is 192.168.170.112/28? *subnetwork address ==================================================== A router determines the path to deliver a packet. What layer of the OSI model does this fact represent? *network ==================================================== What are important characteristics to consider when purchasing a network interface card? (Choose two.) *media used on the network *system bus used on the computer ==================================================== Which subnet masks could be used when subnetting a Class B IP address? (Choose two.) *255.255.255.240 *255.255.192.0 ==================================================== Refer to the exhibit. The network administrator wants to create a subnet for the point-to-point connection between the two routers. Which subnetwork mask would provide enough addresses for the point-to-point link with the least number of wasted addresses? *255.255.255.252 ==================================================== Which characteristics are common to both UDP and TCP? (Choose two.) *uses port numbers *classified as a transport layer protocol ==================================================== Two peer hosts are exchanging data using TFTP. During the current session, a devices fails to arrive at the destination. Which statement is true regarding the retransmission of the devices? *devices retransmission is controlled by the application. ==================================================== Which protocols are TCP/IP application layer protocols? (Choose two.) *TFTP *DNS ==================================================== Which of the following statements are correct about CSMA/CD? (Choose three.) *It is a media access method used in LANs. *When a device needs to transmit, it checks to see if the media is available. *Only one device can successfully transmit at a time. ==================================================== Consider the networks shown in the exhibit. Host A is sending packets to host B. Which layer of the OSI model is being used when the router is making the calculated decision to determine which interface to send the packet out? *network ==================================================== An Ethernet host receives a frame, calculates the FCS, and compares the calculated FCS to the FCS received in the frame. The host finds that the two FCS values do not match. What action will be taken by the host? *The host discards the frame. ==================================================== A computer technician is asked to make a network cable. One end of the cable is pinned as a 568A and the other as a 568B. For what purhuhus can this cable be used? (Choose two.) *to connect a switch to a switch *to connect a hub to a switch ==================================================== Why would a company install a switch instead of a hub when building or expanding a corporate network? *A switch provides more bandwidth by sending frames only out the port to which the destination device is attached. A hub sends the frame out all ports except the source port. ==================================================== Refer to the exhibit. A newly hired technician has a task of terminating CAT 5 UTP cables. The network administrator visually examined the cables the technician terminated. Some of the cables have connectors as shown in the exhibit. What should the network administrator explain to the technician about the cables? *The cable in Graphic A will produce more crosstalk. ==================================================== Refer to the exhibit. What kind of Ethernet cable is represented? *straight-through cable ==================================================== Which cable diagram displays the end to end pinout for a crossover cable used with Cisco devices? *Cable C ==================================================== Refer to the exhibit. Workstation 1 pings the Fa0/1 interface of Router 1. Which MAC address will workstation 1 obtain during the ARP request for this communication? *00-08-A3-B6-CE-02 ==================================================== A technician is testing connectivity between the devices using the ping command. Pings between Host B and Host A were successful. The technician could not ping the R3 address 172.16.3.2 from Host A. The technician issued ipconfig from Host A and saw the information displayed in the exhibit. What is the most likely problem? *The default gateway of Host A is incorrect. ==================================================== Refer to the exhibit. The physical documentation shows a portion of the internetwork of the ABC Company. Which segments will be free of collisions? *segments 3, 4, and 5 ==================================================== The ping command can be used to test connectivity between hosts. Which OSI model layers are verified by this test? *Layers 1, 2 and 3 ==================================================== Which physical network topology is easy to monitor and troubleshoot, easy to add new devices to as the network expands, but subject to complete failure when a central hub or switch ceases to work? *star ==================================================== A network administrator has installed a 24 port switch and connected 10 computers with 10/100 NICs. If the NICs are operating at 100 Mbps, how much bandwidth is available for each computer to receive data? *100 Mbps ==================================================== How many collision domains are shown in the diagram? *seven - Version 3 -
======================================================================================================== Refer to the exhibit. How many broadcast domains are shown? *Three ==================================================== When using Category 5 UTP cable, which RJ-45 pin pairs are used to exchange data between hosts on an Ethernet network? *1 and 2; 3 and 6 ==================================================== Refer to the exhibit. A network administrator has configured a network after subnetting the network number 192.168.0.0/28. Workstation 1 is not able to communicate with Workstation 2. What is the cause of this loss in communications? *Workstation 1 is not on the same network that the Router 1 LAN interface is on. ==================================================== Refer to the exhibit. The hub and the switch are operating using factory default settings. Which hosts will receive the frame if host A transmits a broadcast frame? *Workstations B, C, D, E, and the router will receive the data. ================================================== Refer to the exhibit. A network associate needs to establish an Ethernet connection between Host A and Host B. However, the distance between the two hosts is further than the cabling standards allow. Which two devices that operate at the physical layer of the OSI can be used to allow Host A and Host B to communicate? (Choose two.) *hub*********** *repeater*********** ==================================================== Refer to the exhibit. A network technician is trying to determine the correct IP address configuration for Host A. What is a valid configuration for Host A? IP address: 192.168.100.20; Subnet Mask: 255.255.255.240; Default Gateway: 192.168.100.17 ==================================================== Which devices will create multiple collision domains in an Ethernet network? (Choose two.) *switch
*router ==================================================== Refer to the exhibit. What is the order of the TCP/IP Protocol Data Units as data is moved as indicated through the OSI model? *bits, frames, packets, segments, data ==================================================== Refer to the exhibit. The connections in the exhibit are labeled A through E. Which of these indicate LAN links? (Choose two.) *link A *link E
==================================================== Refer to the exhibit. Which type of UTP cable should be used to connect Host A to Switch1? *straight-through ==================================================== A wireless workstation must scan to find an available access point. What are two characteristics of a wireless workstation in passive scanning mode? (Choose two.) *The wireless node listens for beacons from an access point advertising an SSID and then attempts to join the network
*The wireless node listens for a beacon from an access point with the same WEP key and is allowed to authenticate to the WLAN.
==================================================== ｂａｓｅd on the graphic above, which of the following occurs as each host system comes on line in the topology? *The switch adds MAC address to the bridge table as each host sends a frame. ==================================================== How does a switch learn the addresses of hosts connected to its ports? *The switch reads the source MAC address on incoming frames and records it in CAM. ==================================================== Refer to the exhibit. Which diagram represents the network topology that an administrator would prefer, and why would the administrator prefer it? *Diagram A. It will better provide available bandwidth to the hosts. ==================================================== After an unsuccessful ping to the local router, the technician decides to investigate the router. The technician observes that the lights and fan on the router are not operational. In which layer of the OSI model is the problem most likely occurring? *physical ==================================================== A user initiates three simultaneous FTP connections from the local host to the same FTP server. Which OSI layer is responsible for establishing and managing these different FTP connections? *session ==================================================== Which technologies are considered to be LAN technologies? (Choose two.) *Token Ring
*Ethernet ==================================================== A router interface has been assigned an IP address of 172.16.192.166 with a mask of 255.255.255.248. To which subnet does the IP address belong? *172.16.192.160 ==================================================== What is the correct number of usable subnetworks and hosts for the IP network address 192.168.35.0 subnetted with a /28 mask? *14 networks / 14 hosts ==================================================== In the exhibit, the connections between the devices are labeled A, B, C, D, and E. For each connection, what is the correct UTP cable to use? A=rollover, B=straight, C=straight, D=crossover, E=crossover ==================================================== A network administrator has added a new switch to the network. The new switch connects to an existing switch that is already installed. Which UTP cable correctly connects the new switch to the existing switch? *crossover ==================================================== How many collision domains are shown in the diagram? *three ==================================================== Refer to the exhibit. What must be configured on Host B to allow it to communicate with the file server? (Choose three.) *a unique host IP address
*the subnet mask for the LAN *the default gateway address ==================================================== Refer to the exhibit. Host A pings Host B. What can be concluded about the source and destination addresses contained in the communication sent by Router R5 when it forwards the ping out the Ethernet interface to Host B? (Choose two.) *source MAC address: 5555.AAAA.6666 *destination IP address: 192.168.10.134 ==================================================== What is the decimal representation of the binary number 11111000? *248 ==================================================== 26 A large company has a network that is constantly changing. The routing tables in the routers need to be adjusted to reflect the changes in the routing paths. What type of routing would the network administrator implement? *dynamic routing protocols |
|
||||
Send a private message
Subscribe to RSS feed
Tell a friend
Add to My MSN
Add to your network
Sign up for alerts
|
|
