计算机网络模型与网络设备的工作原理思考

集线器只是用电子器件模拟总线,工作在物理层。

交换机可处理帧工作在数据链路层。

路由器工作在网络层。

强大的网关工作在应用层。

《并行计算:模型与算法》研读兴趣

《并行计算:模型与算法》研读兴趣

  • 概念:并发、并行与分布式

    并发:多个线程在同一时间段内同时执行。更多地考虑控制问题,包括同步和互斥等经典问题。

    并行:多个线程在同一时刻同时执行。主要面向具体计算问题。

    分布式:多个进程在多个通过网络互联的处理器上同时执行。

  • 回顾算法复杂度的概念

    复杂度表示所用到的符号有:

    • $f(n)=\Theta(g(n))$: 存在常数$c_1 \ge 0$,$c_2 \ge 0$,以及正整数$n_0$,对所有$n \ge n_0$有$0 \le c_1 g(n) \le f(n) \le c_2 g(n)$。

    • $f(n)=O(g(n))$: 存在常数$c_1 \ge 0$,以及正整数$n_0$,对所有$n \ge n_0$有$0 \le f(n) \le c_1 g(n)$。

    • $f(n)=\Omega(g(n))$: 存在常数$c_1 \ge 0$,以及正整数$n_0$,对所有$n \ge n_0$有$0 \le c_1 g(n) \le f(n)$。

    • $f(n)=o(g(n))$: 对任意$c_1 \ge 0$,存在正整数$n_0$,对所有$n \ge n_0$有$0 \le f(n) \le c_1 g(n)$。

  • 针对并行计算,具有研究价值的算法的简要描述

    • 最大值。输入为一个数组$A[n]={a_1,\dots,a_n}$,输出该数组中最大值。

    • 矩阵转置。输入为一个按行存储的矩阵$A[n][n]={ a_{11},\dots,a_{1n};a_{21},\dots,a_{2n};\dots;a_{n1},\dots,a_{nn} }$,输出为矩阵的转置$A’[n][n]={ a_{11},\dots,a_{n1};a_{12},\dots,a_{n2};\dots;a_{1n},\dots,a_{nn} }$。

    $$A’[n][n]={ a_{11},\dots,a_{n1};a_{12},\dots,a_{n2};\dots;a_{1n},\dots,a_{nn} }$$

    {$A’[n][n]={ a_{11},\dots,a_{n1};a_{12},\dots,a_{n2};\dots;a_{1n},\dots,a_{nn} }$}

【170305】TOEFL复习

http://mp.weixin.qq.com/s/bqXUoVCAMHki-FI2w0svRQ

A degree achieved at collage can prepare undergraduates for social entrance. Not only can students obtain textbook knowledge related to their areas of study, but they also acquire various helpful skills even after their graduation. Collages advocate independent thoughts and innovation. After-class activities such as student communities and the confederacy of student provide with worthwhile opportunities

A university degree can better prepare students to enter society. Not only students gain textbook knowledge relating to their specific majors, but they also acquire various that may help them after graduation. Universities always encourage liberal thoughts and creativity. Extracurricular activities such as student clubs and student governments provide students with opportunities to practice their social skills through organizing and supervising meetings and managing funds. All these skills will benefit them for their future careers.

构建下一艘“核动力航母”

Reference

Single CPU performance
Single thread performance
Multiple CPU performance

Remarks on the first “Craft Vessel”

  • E3-1231 V3 gets the almost highest efficiency price ratio.
    The integrated graphic with Intel QSV technology is not necessary. Also, the single core performance of the CPU turns out to be satisfying, even without locking the frequency multiplier at 38x.
    If an iGPU were to be appended, E3-1246 v3 are most likely to be accessible. However it is approximate to i7-4770/4790.
  • B85 chipset costs a lot less than Z97,yet supports frequency locking and over-clocking.
  • Kingston Hyper Fury DDR3 RAMs are not economical compared with others.

Orientation for the next “Nuclear Craft Vessel”

  • B350 motherboards compatible with Ryzen 7 can be a waste.
  • A320 motherboards have not been launched yet.
  • X99 with DDR4 RAM is quite different from X79 with DDR3.
  • E5-2683 v3 has numerous cores and is affordable, but is not so ideal for its single thread performance.
  • E5-2637 v3 has strengthful single thread performance, but doesn’t have so many cores.
  • Double E5-1620 v3 remain to be inspected.

拼尽全力,刷机!解锁!ROOT!

本设备是Redmi Note 2.

在种种失败尝试中,驱动程序不正常是最大的敌人。

有必要先在设备管理器中卸载设备,并勾选删除驱动程序。分别在正常启动、Recovery模式、Fastboot模式下连接并删除驱动。

正常启动后,在小米助手中连接,断开,再连接,务必让驱动安装上。

接下来即可线刷刷入Recovery,撞开了root的大门。

Root后将会出现一个重要appSuperSU.

解锁尚未成功,因为fb模式下设备信息无法识别,但暂时没有必要了。


Failed attempts:

http://www.netded.com/a/jingpinshouji/2015/1003/30934.html

http://www.netded.com/a/jishuyingyong/2015/0601/30600.html

Windows7 UEFI安装备忘录

  • Win7 MSDN安装镜像中缺少了必要的UEFI引导文件,即来自Win8及以后系统的bootmgfw.efi,将其改名并放在合适目录下。

  • 如果采用U盘引导启动,那么“升级”安装往往不能进行。可能需要硬盘引导启动,或者在已正常启动的Win7系统中运行安装程序,而不是系统崩溃后再去“升级”安装。

  • Windows启动修复主要针对系统引导文件,一定条件下能够重建启动引导菜单。

  • 若有GPT分区表硬盘与MBR分区表硬盘共存,GPT分区表上的bootmgfw.efi不能正常引导启动。

新游戏构思

现在的手机VR太没劲,如果开发出东方VR是不是能有可玩性?


那也得有一套玩法才行。
有个合适的界面布局。

Visual Studio - NET开发杂项

Visual Studio shortcut keys

  • error C2011: ‘’ : ‘class’ type redefinition

    #pragma once

  • C#语言编写风格

    将C++中的->,::,.合并为一种运算符应当是很有意义的。
    在编写托管程序时相当具有优势,不必再纠结于*与^,new与gcnew。
    using语句块可体现其独特性。

  • StreamReader类

    StreamReader不仅采用流的方式,而且对于操作系统中文件的处理更具功能性,能修正字符集错误。

    using (StreamReader sr1 = new StreamReader(FILE_INFO_NAME,UnicodeEncoding.GetEncoding(“GB2312”)));
    StreamReader reader=new StreamReader(fileName,System.Text.Encoding.Default)

  • One-Click Publish

    对于使用C#开发的项目,Visual Studio提供了Click-once App打包方式。
    打包时为了让资源文件也能被包含在生成文件中,需将相关文件build action改为Content。

  • 发布独立可执行文件的注意事项

    不要随便拿个Debug生成的可执行文件扔给老哥。
    Debug 和 Release 的真正秘密,在于一组编译选项。
    注意工具集和平台运行库的选择。
    MFC的使用方式。

2016-2017 SSL证书更新

在前证书过期一周有余,期末考试完成之后,新的SSL免费证书总算申请上了。

WoSign竟然早已关闭了免费证书申请。这次是向腾讯云申请到的。