sheerdns is a master DNS server whose zone records are stored on a One-Record-Per-File bases. Because of this, it is the simplest of any DNS to configure, the easiest to update, and the most efficient for networks that experience a lot of updates (for example master servers for dynamic IP address ranges). You never have to restart it; any updates are available immediately without having to notify the sheerdns process. 來源: http://freshmeat.net/projects/sheerdns/?topic_id=149 sheerdns是一個主DNS服務(wù)器，它的域記錄保存在一個One-Record-Per-File（每文件一個記錄）的庫中。因此，它是最簡單的DNS配制，最容易更新，對于有大量更新的網(wǎng)絡(luò)（如動態(tài)IP地址范圍的主服務(wù)器）來說它是最高效的。你不必重新啟動它，任何更新不用通知對應(yīng)DNS進程就可以立即生效。
CRC碼產(chǎn)生器與校驗器程序
Features ：
Executes in one clock cycle per data word
Any polynomial from 4 to 32 bits
Any data width from 1 to 256 bits
Any initialization value
Synchronous or asynchronous reset
樣板 B 樹 ( B - tree )
規(guī)則 :
(1) 每個節(jié)點內(nèi)元素個數(shù)在 [MIN,2*MIN] 之間, 但根節(jié)點元素個數(shù)為 [1,2*MIN]
(2) 節(jié)點內(nèi)元素由小排到大, 元素不重複
(3) 每個節(jié)點內(nèi)的指標(biāo)個數(shù)為元素個數(shù)加一
(4) 第 i 個指標(biāo)所指向的子節(jié)點內(nèi)的所有元素值皆小於父節(jié)點的第 i 個元素
(5) B 樹內(nèi)的所有末端節(jié)點深度一樣
