The Twelve Networking Truths

Status of this Memo

   This memo provides information for the Internet community.  This memo
   does not specify an Internet standard of any kind.  Distribution of
   this memo is unlimited.

Abstract

   This memo documents the fundamental truths of networking for the
   Internet community. This memo does not specify a standard, except in
   the sense that all standards must implicitly follow the fundamental
   truths.

Acknowledgements

   The truths described in this memo result from extensive study over an
   extended period of time by many people, some of whom did not intend
   to contribute to this work. The editor merely has collected these
   truths, and would like to thank the networking community for
   originally illuminating these truths.

1. Introduction

   This Request for Comments (RFC) provides information about the
   fundamental truths underlying all networking. These truths apply to
   networking in general, and are not limited to TCP/IP, the Internet,
   or any other subset of the networking community.

2. The Fundamental Truths

   (1)  It Has To Work.

   (2)  No matter how hard you push and no matter what the priority,
        you can't increase the speed of light.

        (2a) (corollary). No matter how hard you try, you can't make a
             baby in much less than 9 months. Trying to speed this up
             *might* make it slower, but it won't make it happen any
             quicker.

   (3)  With sufficient thrust, pigs fly just fine. However, this is
        not necessarily a good idea. It is hard to be sure where they
        are going to land, and it could be dangerous sitting under them
        as they fly overhead.

   (4)  Some things in life can never be fully appreciated nor
        understood unless experienced firsthand. Some things in
        networking can never be fully understood by someone who neither
        builds commercial networking equipment nor runs an operational
        network.

   (5)  It is always possible to aglutenate multiple separate problems
        into a single complex interdependent solution. In most cases
        this is a bad idea.

   (6)  It is easier to move a problem around (for example, by moving
        the problem to a different part of the overall network
        architecture) than it is to solve it.

        (6a) (corollary). It is always possible to add another level of
             indirection.

   (7)  It is always something

        (7a) (corollary). Good, Fast, Cheap: Pick any two (you can't
            have all three).

   (8)  It is more complicated than you think.

   (9)  For all resources, whatever it is, you need more.

       (9a) (corollary) Every networking problem always takes longer to
            solve than it seems like it should.

   (10) One size never fits all.

   (11) Every old idea will be proposed again with a different name and
        a different presentation, regardless of whether it works.

        (11a) (corollary). See rule 6a.

   (12) In protocol design, perfection has been reached not when there
        is nothing left to add, but when there is nothing left to take
        away.

Security Considerations

   This RFC raises no security issues. However, security protocols are
   subject to the fundamental networking truths.

References

   The references have been deleted in order to protect the guilty and
   avoid enriching the lawyers.

Author's Address

   Ross Callon
   Internet Order of Old Farts
   c/o Bay Networks
   3 Federal Street
   Billerica, MA  01821

   Phone: 508-436-3936
   EMail: rcallon@baynetworks.com

新特性包括：
Process Tracking: Now you can identify rogue applications sending network data! View all the processes on your machine generating network traffic (process name and PID). Use the conversation tree to view frames associated with each process.
也就是说，可以选择一组程序（这组程序可能是不相关的软件），监视它们的网络通讯

§ Capture engine re-architecture to improve capture rate in high-speed networks. Network Monitor 3.2 drops significantly fewer frames that Network Monitor 3.1.

§ Find conversations: You asked for this. Many of our users found conversation tracking to be difficult to use as the view grew hard to manage, and it was difficult to correlate the frames they were seeing with the conversation nodes in the tree. Now, you can quickly isolate frames in the same network conversation. Just right-click on a frame and select a conversation to track, and you will see all the frames in that conversation. View TCP streams, HTTP flows etc.

§ Extensive parser set: Parsers for over 300 protocols! As before, the parsers are fully customizable.

§ Better parser management: By default only a subset of parsers are loaded. You can load the full parser set by going to Tools>Options>Parser and choose Full vs. Stub implementations.

§ CodePlex Ready: In the upcoming months, we plan to place all our Windows parsers on the Microsoft open-source CodePlex site and allow the community to modify and contribute parsers. You can find out more information on this here. This version of Network Monitor seamlessly integrates new parser packages.
微软准备将源代码发布出来了！

§ Network Monitor API: Create your own applications that capture, parse and analyze network traffic!

§ More extensive documentation of the API and NPL. Access the documentation from Help > NPL and API Documentation.

§ IA64 builds.

§ PCAP capture file support*.

§ ContainsBin Plug-in: Search frames for arbitrary byte sequences or strings.

§ . and more. See our Release Notes in the Help directory of the installation folder for a complete list of new features and known issues.

Enjoy!

for i in coins:
    while counter < num:
        if counter + i > len(pos) - 1:
            for j in range( counter + i ):
                pos.append(0)
        if counter != 0:
            pos[counter + i] = pos[counter + i] + pos[counter]
        else:
            pos[counter + i] = pos[counter + i] + 1
        counter = counter + 1
    counter = 0

print pos[num]

有两种选择
GCC 4.3.0-tdm-2 (Default SJLJ exceptions) 和 GCC 4.3.0-tdm-2 With DW2 Exceptions
可以根据SJLJ or DW2 (Dwarf-2) 异常模型来选择需要下载的版本，通常情况下win32平台下选择SJLJ（set jump long jump）模型

然后还需要去Mingw官网下载
binutils
http://downloads.sourceforge.net/mingw/binutils-2.18.50-20080109-2.tar.gz
mingw-runtime (mingw-runtime-3.14.tar.gz, 494KB)
http://downloads.sourceforge.net/mingw/mingw-runtime-3.14.tar.gz
w32api (w32api-3.11.tar.gz, 1.55MB)
http://downloads.sourceforge.net/mingw/w32api-3.11.tar.gz

也可以选择安装以下组件
mingw-utils
http://downloads.sourceforge.net/mingw/mingw-utils-0.3.tar.gz
mingw32-make（可以选择最新的mingw32-make-3.81-20080326-2）
http://downloads.sourceforge.net/mingw/mingw32-make-3.81-2.tar.gz
gdb（可以选择最新的6.8试验版）
http://downloads.sourceforge.net/mingw/gdb-6.6.tar.bz2

把这些东西都下载下来，然后解压到不同的目录，每个目录里面大概都会有bin，include，lib，man这样的目录，要做的就是合并它们，也就是拷贝到同一个目录里面，注意可能有些文件会重复，一般来说GCC 4.3.0 TDM包里面的文件比较重要，不要用其他的包里面的文件覆盖了它

然后就可以得到一个完整包含gcc，g++，binutils，gdb，make等的目录了，此时，在windows环境变量中的path变量里面添加该目录的bin子目录，就可以在cmd窗口中调用gcc和g++进行编译了。如果你不想污染了环境变量，也可以写个bat：(假设你的mingw目录是C:\mingw\bin)
set path=C:\mingw\bin;%path%"

现在还没有结束，需要进行两个地方的设置
1 make
mingw官方提供的make工具，名称不是简单的make，而是mingw32-make.exe，把它改名成make.exe或者复制一份为make.exe都可以

2 gcc: CreateProcess: No such file or Directory 错误
这个问题在google里面很多人发问，但是没有一个完整的解答，下面给出一个完整的解答
产生这个错误有两个原因：
第一是gcc无法找到安装目录里面的libexec目录里面的工具，通常这些工具包括cc1.exe，cc1plus.exe，collect2.exe，它们通常存放在：
安装目录\libexec\gcc\mingw32\4.3.0
第二是gcc无法找到mingw目录里面binutils的工具，它们通常存放在
安装目录\mingw32\bin
这两个目录的名字并不完全固定，根据不同组织编译的gcc各有不同，比如mingw官方编译的gcc4.3.0 alpha，上述目录就是
安装目录\gcc\i386-pc-mingw32\4.3.0
而官方提供的binutils包里面是
安装目录\i686-pc-mingw32\bin

只要这两个地方没有设置好，就可能导致CreateProcess错误，那么，有没有什么好办法能够确定这里应该怎样命名呢？办法是用16进制编辑器打开gcc.exe，搜索GCC_EXEC_PREFIX，当搜索到该字符串（不止一个）时，观察后面是否出现版本号4.3.0，如果出现，后面紧接着的就是路径，如果是mingw32那么上面的命名就应该是
安装目录\libexec\gcc\mingw32\4.3.0
安装目录\mingw32\bin

如果是其他的例如i686-pc-mingw32，那么名称相应的变为
安装目录\libexec\gcc\i686-pc-mingw32\4.3.0
安装目录\i686-pc-mingw32\bin

好了，可以测试一下你的hallo world程序了^_^