摘要：raid级别你选谁（下） 一般常用的raid阶层，分别是raid 0、raid1、raid 3、raid 4以及raid 5，再加上二合一型 raid 0+1﹝或称raid 10﹞。我们先把这些raid级别的优、缺点做个比较： raid级别 相对优点 相对缺点 raid 0 存取速度最快 没有容错 raid 1 完全容错 成本高 raid 3 写入性能最好 没有多任务功能 raid 4 具备多任务及容错功能 parity 磁盘驱动器造成性能瓶颈 raid......
摘要：曾经用access生成一个超复杂的sql语句,用了很多left join ...on ,然后检索的每一个字段都必须加上group by,任何一个去掉都产生错误,我一直不明白为什么这样,然后昨天在csdn上面提问了,但是还是没能明白.今天再次用两表连接查询然后group by,好像页必须所有检索字段都加入才成.
eg:
select supplier.id as supplierid,supplier.shortname as supplier from......
Opensource Project Proposal on JXTA.org: JXTA VoIP
【相关文章:
[CODE] tcpserver完整的p】about this proposal: 【扩展阅读:
关于CSDN Blog的一点想法】
1. backgroud 【扩展信息:
保护Applet免遭"窃取&q】
2. sip brief intro
3. sip vs. jxta
4. disvoip bootstrap
part1: background
wireless telephony in the future, 3g? we maybe want to have some alternatives, such as using the wi-fi and skype on wince, thought it’s seems somehow awkward, but 802.16 and the wimax/wi-fi combined wireless world vision did incited my imagination to pursue the possibly, the so-call “wimax phone”: a hand-held device provides voip and multimedia service which highly relevant to web. no matter it’s hype or not: but i did see skype becoming popular, while none of them think they would use skype to dial an emergency number.
i believe wireless voip will be popular, as the wireless network and hand-held device evolves, and it will be revolutionary, so it’s time to start something, proposing project, named disvoip (distributed voice over ip).
skype is a p2p application, i didn’t get who it works, but as the same to many p2p applications, you need a identity, and a network get the line to you correctly all behind the scene.
so i looked for some open standards suits such job. sip is indented from the bottom.
part2: sip brief intro
here is a simple digestion of what sip is from sipcenter.com; hopefully you can get the picture that how it looks like the jxta.
...
下一页 摘要：
daniel robbins总裁兼 ceo，gentoo technologies, inc.2000 年 4 月
在前一篇 bash 的介绍性文章中，daniel robbins 为您讲解了脚本语言的一些基本元素和使用 bash 的原因。在本文（即第二部分）中，daniel 继续前一篇的内容，并讲解条件 (if-then) 语句、循环和更多的 bash 基本结构。
我们先看一下处理命令行自变量的简单技巧，然后再看看 bash 基本编程结构。
接......
