灌溉梦想，记录脚步
2010-01-25关注学习

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Linux NFS Root and PXE-Boot

Linux kernel hacking and test running on the same machine becomes a major pain. This tutorial explains how to separate the two easily for a quick code-and-test loop. This tutorial explains how to setup a Linux thin client that boots using PXE by pulling a remote Linux kernel image and mounting a remote root file system over NFS. This is only possible if your client machine has a network card that supports this (do you remember seeing some type of option like press N to boot from network just after posting?). I am using Fedora Core 5 as my server, so some of the details may be specific to FC.

Most of the details of setting up the PXE boot server were found at Setting up a PXE-Boot Server.

1) yum install tftp-server dhcp
Make sure you have an NFS server.

2) create /etc/dhcpd.conf
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2010-01-25关注学习

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PXELINUX

What is PXELINUX?

PXELINUX is a SYSLINUX derivative, for booting Linux off a network server, using a network ROM conforming to the Intel PXE (Pre-Execution Environment) specification. PXELINUX is not a program that is intended to be flashed or burned into a PROM on the network card; if you want that, check out Etherboot ( http://www.etherboot.org/).

If you want to create PXE-compliant boot PROM for your network card (to use with PXELINUX, for example), check out NetBoot (http://netboot.sourceforge.net/).

How do I Configure PXELINUX?

PXELINUX operates in many ways like SYSLINUX. If you are not familiar with SYSLINUX, read the SYSLINUX FAQ first, since this documentation only explains the differences.

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2010-01-25关注学习

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Setting up a PXE-Boot Server

This documents how to setup a PXE boot server for Linux. This assumes that you’re using Redhat/FC as the PXE boot server. The vast majority of the information has been obtained from the following webpages:

http://dev.brantleyonline.com/wiki/index.php/General_Network_%28PXE%29_Booting
http://dev.brantleyonline.com/wiki/index.php/PXE_Booting_-_Fedora_Core

0) The first thing to note is that you need to setup your own mini-network that is completely disconnected from the network, since part of this process requires setting up a DHCP server which could conflict with the corporate DHCP server if they were both running on the same network simultaneously. So get yourself a switch from IT up front. You do *NOT* need the switch immediately, so just put it aside until I mention it again
later on.

1) The next step is to choose a box to be the PXE boot server. This can really be any box at all, as long as you have a NIC in it that works reliably under Linux. For the purposes of this documentation, I’m going to assume that you’ve loaded Fedora Core 4 on this box (do that now, if you’ve not already). Get this box onto the network with DHCP (just like a normal installation).
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2010-01-20关注学习

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100个句子等于7000个单词

1. Typical of the grassland dwellers of the continent is the American antelope, or pronghorn.

1.美洲羚羊，或称叉角羚，是该大陆典型的草原动物。

2. Of the millions who saw Haley’s comet in 1986, how many people will live long enough to see it return in the twenty-first century.

2. 1986年看见哈雷慧星的千百万人当中，有多少人能够长寿到足以目睹它在二十一世纪的回归呢？

3. Anthropologists have discovered that fear, happiness, sadness, and surprise are universally reflected in facial expressions.

3.人类学家们已经发现，恐惧，快乐，悲伤和惊奇都会行之于色，这在全人类是共通的。

4. Because of its irritating effect on humans, the use of phenol as a general antiseptic has been largely discontinued.

4.由于苯酚对人体带有刺激性作用，它基本上已不再被当作常用的防腐剂了。
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2009-11-17关注学习

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研华ARK-1310入门工控机

研华ARK-1310 支持2个USB 2.0接口、2个LAN端口、4个COM端口和研华EVA-X4150处理器，都由一个小巧、坚固的机箱保护。4个COM端口都支持RS232/422/485自动流控功能。紧凑型ARK-1310嵌入式机箱配有一个高达8 GB的固态板载CF卡，可轻松地通过50和5 Grms的冲击和振动测试。ARK-1310支持9 VDC ~ 24 VDC的宽范围电压输入。
研华ARK-1310 可作为独立平台应用控制工程网版权所有，也可通过壁挂式、DIN导轨或VESA悬臂等安装方式嵌入式在大型系统中应用。ARK-1310的坚固铝制机箱外壳不仅能够为系统提供EMI、冲击/振动、热/冷保护www.cechina.cn，还能够为安静的无风扇运行提供被动冷却方案。较低的功耗使ARK-1310成为一款冷却运行的嵌入式工控机。
小巧紧凑
和研华ARK-1300系列的其它产品一样，ARK-1310 的尺寸仅为189 mm x 130.6 mm x 41 mm (7.44" x 5.14" x 1.61")，能够满足1U高度要求。因此www.cechina.cn，该款机箱非常适合于各种空间有限应用CONTROL ENGINEERING China版权所有，如自助服务终端和I\O控制系统。
丰富IO接口
ARK-1310提供了4个带自动流控功能的RS-232/422/485端口、2个USB接口、2个LAN端口和8位可编程数字量IO。此外，宽范围的电压输入使之非常适合于各种嵌入式控制应用。
经济高效
ARK-1310 采用单主板架构和低功耗的研华嵌入式EVA-X4150 SOC。较低的购置成本、电源要求、运行成本和较长的服务期限使得该款产品成为一款经济高效的高性能工业机箱。
ARK-1310 适用于各种坚固耐用的无风扇工作系统，如自助服务终端、网关控制器、产品线自动化、IO控制系统、数据采集和传输以及一般的自动化控制器等应用。
注：ARK-1310 可选用Windows CE 5.0、Linux或DOSwww.cechina.cn，不带硬盘驱动器；不适用于XP或XPe。
ARK-1310 为系统集成商提供了功能丰富、即开即用的应用，从而可以有效缩短开发时间。更多ARK-1310的相关信息，请联系研华公司当地销售代表或访问研华网站：http://www.advantech.com.cn/products/ARK-1310/mod_1-3DK668.aspx

2009-11-12关注学习

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RouerOS DDNS 设置方法

先到www.changeip.com填写注册申请，并添加一个域名。

并在RouterOS的调度程序中添加下列代码：

:log info "DDNS: Begin"
:global ddns-user "你的用户名"
:global ddns-pass "你的密码"
:global ddns-host "*1"
:global ddns-interface "外网拨号线路，比如（pppoe-out3）"
:global ddns-ip [ /ip address get [/ip address find interface=$ddns-interface] address ]
:if ([ :typeof $ddns-lastip ] = nil ) do={ :global ddns-lastip 0.0.0.0/0 }
:if ([ :typeof $ddns-ip ] = nil ) do={
:log info ("DDNS: No ip address present . " . $ddns-interface . ", please check.")
} else={
:if ($ddns-ip != $ddns-lastip) do={
:log info "DDNS: Sending Update!"
:log info [ /tool dns-update name=$ddns-host address=[:pick $ddns-ip 0 [:find $ddns-ip "/"] ] key-name=$ddns-user key=$ddns-pass ]
:global ddns-lastip $ddns-ip
} else={
:log info "DDNS: No change"
}
}
:log info "DDNS: End"

2009-11-04关注学习

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磁盘阵列技术-术语汇编

STP：IEEE Std 802.1D-1998定义，不能快速迁移。即使
是在点对点链路或边缘端口，也必须等待2倍的forward delay
的时间延迟，网络才能收敛。

RSTP：IEEE Std 802.1w定义，可以快速收敛，却存在以
下缺陷：
局域网内所有网桥共享一棵生成树，不能按vlan
阻塞冗余链路。

MSTP可以弥补这样缺陷，它允许不同vlan的流量
沿各自的路径分发，从而为冗余链路提供了更好的
负载分担机制。

MSTP：
Multiple Spanning Tree Protocol
多生成树协议
在规范IEEE Std 802.1s中第13节描述。
MSTP算法通过应用MSTP、STP或RSTP的桥任意互连的桥接网络，为分配给任一个特定VLAN的帧提供了简单而完备的连通性。
MSTP允许不同VLAN的数据从各自的路径分发。各条路径建立在由LAN和MST桥组成的MST域中的各个独立的多生成树实例的基础上。

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