IPad,IPhone,IPod 使用一般電腦USB充電方法

一般電腦USB 因輸出電流過小(USB介面標準最大輸出電流量只有500mA),而無法對IPad,IPhone...等device進行充電。Apple為了加快充電 速度，進而設計出「快速」和「慢速」兩種充電模式。iPad電池容量大，被設定在需要約1A（1000mA）以上的電流量，才能進入慢速充電模式，因此有 許多電腦無法為它充電。至於iPhone、iPod Touch，單純連接電腦是屬於慢速充電模式，想進入快速充電模式，電流量則是必需達到0.7A（700mA）左右。

透過安裝下列軟體,可以使USB送出模擬偏壓訊號的方式，讓裝置以為是連接到變壓器，進而啟動充電模式。

ASUS Ai charger:  http://dlcdnet.asus.com/pub/ASUS/misc/utils/AiCharger_V10006_XpVistaWin7.zip

SNAT V.S MASQUERADE

SNAT改變包的源位址，這在極大程度上可以隱藏你的本地網路或者DMZ等。一個很好的例子是我們知道防火牆的外部位址，但必須用這個位址替換本地網路位 址。有了這個操作，防火牆就 能自動地對包做SNAT和De-SNAT(就是反向的SNAT)，以使LAN能連接到Internet。
 
MASQUERADE的作用和SNAT完全一樣，只是電腦 的負荷稍微多一點。因為對每個匹配的包，MASQUERADE都要查找可用的IP地址，而不象SNAT用的IP位址是配置好的。當然，這也有好處，就是我 們可以使用通過PPP、 PPPOE、SLIP等撥號得到的地址，這些位址可是由ISP的DHCP隨機分配的。

How to overclock RB450G/RB750G from 600Mhz to 800Mhz

Login RouterOS terminal

then type :
                    /system routerboard settings set cpu-frequency=800

ubuntu 10.0 4 重設root密碼方法

1. 開機時先進入到GRUB,選擇Recovery Mode後,按 "e" 進入編輯模式
2. 把最後面 "ro single" 改成 "rw single init=/bin/bash"

按 ctrl+x 去boot 便可以用root單人模式 login,再用passwd 修改root密碼即可!

Mapping IP Multicast to MAC-Layer Multicast

To support IP multicasting, the Internet authorities have reserved the multicast address range of 01-00-5E-00-00-00 to 01-00-5E-7F-FF-FF for Ethernet and Fiber Distributed Data Interface (FDDI) media access control (MAC) addresses. As shown in Figure 4.1, the high order 25 bits of the 48-bit MAC address are fixed and the low order 23 bits are variable.
Figure 4.1 Mapping IP Multicast Addresses to Ethernet and FDDI MAC Addresses
To map an IP multicast address to a MAC-layer multicast address, the low order 23 bits of the IP multicast address are mapped directly to the low order 23 bits in the MAC-layer multicast address. Because the first 4 bits of an IP multicast address are fixed according to the class D convention, there are 5 bits in the IP multicast address that do not map to the MAC-layer multicast address. Therefore, it is possible for a host to receive MAC-layer multicast packets for groups to which it does not belong. However, these packets are dropped by IP once the destination IP address is determined.
For example, the multicast address 224.192.16.1 becomes 01-00-5E-40-10-01. To use the 23 low order bits, the first octet is not used, and only the last 7 bits of the second octet is used. The third and fourth octets are converted directly to hexadecimal numbers. The second octet, 192 in binary is 11000000. If you drop the high order bit, it becomes 1000000 or 64 (in decimal), or 0x40 (in hexadecimal). For the next octet, 16 in hexadecimal is 0x10. For the last octet, 1 in hexadecimal is 0x01. Therefore, the MAC address corresponding to 224.192.16.1 becomes 01-00-5E-40-10-01.
Token Ring uses this same method for MAC-layer multicast addressing. However, many Token Ring network adapters do not support it. Therefore, by default, the functional address 0xC0-00-00-04-00-00 is used for all IP multicast traffic sent over Token Ring networks. For more information about Token Ring support for IP multicasting, see RFC 1469.

jperf 圖形(GUI) 介面的 iperf

jperf 是有圖形 GUI 介面的 iperf,不過他是架構在 iperf 必須先安裝過 iperf 才可以使用.下載點在 http://code.google.com/p/xjperf/downloads/list 方式也很簡單,先行安裝完 iperf . 再解開 jperf 即可執行

How to copy svn working dir without svn hidden dirs and files

rysnc is a very powerful alternative to cp. It provides basic things like you want here, progress meters, copying to remote sites, a diff algorithm to efficiently maintain mirrors, compression, etc.

I think you want something like this:

Code:

rsync -r --exclude=.svn /home/user/progname/ /home/user/progname.copy