some ways to recover loss packet

o. FEC (forward error correction)

o. Interleaving

o. Packet Repetition

o. Interpolation

memset 問題

Function: void * memset ( void * ptr, int value, size_t num );

Today, when I use memset function to initialize a buffer to "0" , I found that the number of byte must to the actually byte of the buffer+1..

However, The third variable of memset is Number of bytes to be set to the value.

Still don't know the reason of this

如何在codeblocks設定連結winsock library

exec codeblocks

Settings > Compiler and Debugger > Linker Settings > Add >

Go to CodeBlocks Folder (normally C:\Program Files\CodeBlocks)

then MingW then libs and find libws2_32.a and add it.

what is analysis exactly?

Analysis is the process of breaking a complex topic or substance into smaller parts to gain a better understanding of it.
(from wikipedia)

製作強制關機捷徑 on windows

1. 在桌面按右鍵->新增->捷徑

2. 在輸入項目的位置處 輸入 shutdown -s -t 50 -c "shutdown message"意思是系統會在50秒內強制關機

3. 按下一步完成

4. 點選剛剛新增好的捷徑測試

warning: 請先存檔尚未儲存的檔案

very humorous R example code

fun <- function() {

ANSWER <- readline("Are you a satisfied R user? ")

if (substr(ANSWER, 1, 1) == "n")

cat("This is impossible. YOU LIED!\n")

else

cat("I knew it.\n")

}

fun()

[LOOP] loop problem

問題:

mac address 衝突 產生 loop message - loop(1) xx.xx.xx.xx.xx.xx to ex1 from ex0. (active)

解決過程:

先看到錯誤訊息, 把訊息中ip mac 傳送的source and destination 畫出來.

發現從不同網卡傳送的封包具有相同的mac address. 結果發現ap 與我的電腦的mac address竟然一樣.

就發現當初在設定ap的時候有個功能是複製你的PC的mac address. 這個功能可能是為了方便填寫mac.

然後你自己要在修改mac address. 不知道為什麼ap 沒有自己預設的mac address而要自己設置.

linux and human.

[bug] x200 has 48 hours battery life