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Friday, September 3, 2010

A Guide to Today's Top 10 Linux Distributions

http://www.pcworld.com/businesscenter/article/204767/a_guide_to_todays_top_10_linux_distributions.html?tk=hp_new

One of the most confusing things for the newcomer to Linux is how many distributions, or versions, of the operating system there are. Ubuntu is the one most people have heard of, but there are hundreds of others as well, each offering some variant on the basic Linux theme.

Choosing the distribution--or "distro"--that's right for your business will depend in large part on five key factors, as I've already described. It's also helpful, however, to have a basic understanding of how the major Linux distros differ.

What follows, then, is a roundup of sorts of the top 10 Linux distributions today.

1. Ubuntu

Yes, Ubuntu has become the poster child for Linux these days, and no wonder--it's the most popular distro by far, garnering more than 2,200 hits per day on the Distrowatch site alone, compared with some 1,400 for Fedora, the No. 2 contender.

Ubuntu is actually a relatively late arrival on the Linux scene, having been announced in just 2004, but it's more than made up for that shorter history. Founded by South African millionaire Mark Shuttleworth, Canonical--the company behind Ubuntu--for many years shipped Ubuntu CDs to interested users for free, thus speeding its market penetration.

Ubuntu is based on Debian (see below) and includes well-known apps such as Firefox andOpenOffice.org. It has a predictable, six-month release schedule, with occasional Long Term Support (LTS) versions that are supported with security updates for three to five years.

Ubuntu is also notable for its ease of use and its inclusion of a migration assistant for Windows users and support for the latest technologies. Version 10.10 of Ubuntu--also known as Maverick Meerkat--will include a multitouch and gesture stack. The final iteration of that version is due out next month.

It's also worth understanding that Ubuntu is available in various remixes and spin-off sub-distros targeted at specific niches, such as Kubuntu, Xubuntu and Lubuntu. Most of these differ primarily by offering a desktop environment other than Ubuntu's standard GNOME.

2. Fedora

Fedora is the free version of Red Hat, whose RHEL (Red Hat Enterprise Linux) has been a commercial product since 2003. Because of that close connection, Fedora is particularly strong on enterprise features, and it often offers them before RHEL does.

Fedora also offers a six-month release schedule, and its security features are excellent. While some have viewed it as a cutting-edge distro for the Linux "hobbyist," I think improvements over the years and widespread popularity have combined to make it a good choice for newer Linux users as well.

3. Linux Mint

Currently in Distrowatch's third spot in popularity, Linux Mint is an Ubuntu-based distro that was just launched in 2006. The operating system adds to Ubuntu with its own, distinct desktop theme and a different set of applications; also unique to the distro are a variety of graphical tools for enhanced usability, such as mintDesktop for configuring the desktop environment, mintInstall for easier software installation and mintMenu for easier navigation.

Mint enjoys a well-deserved reputation for ease of use, so it's another good one for beginning users. It also includes some proprietary multimedia codecs that are often absent from larger distributions, thereby enhancing its hardware compatibility. Mint doesn't have a fixed release schedule, but typically a new version comes out shortly after each stable Ubuntu release.

4. openSUSE

With some 1,200 hits per day on Distrowatch, openSUSE holds the No. 4 spot in popularity on the site and is also the foundation for Novell's SUSE Linux Enterprise Desktop and SUSE Linux Enterprise Server products.

The package's administration utility, YaST, is widely acknowledged as one of the best, and its boxed edition comes with some of the best printed documentation you'll find for any distro. I'd say openSUSE rates a "medium" on difficulty level.

5. PCLinuxOS

Rather than GNOME, PCLinuxOS uses the KDE desktop environment and is essentially a lighter-weight version of Mandriva (see below). With good support for graphics drivers, browser plugins and media codecs, PCLinuxOS can be a good choice for beginners. Its release cycle can be erratic, though, and there is also no 64-bit version of the software.

6. Debian

Dating back to 1993, Debian is currently known as one of the most well-tested and bug-free distros available today. Though it serves as the foundation for Ubuntu, most view Debian as a distro best-suited for those experienced with Linux. The distro uses all open-source components, which is a good thing, but means it can be more difficult to achieve compatibility with proprietary code such as wireless network drivers. Debian also has a relatively slow release cycle, with stable ones coming out every one to three years.

7. Mandriva

Formerly known as Mandrake, Mandriva is notable for its cutting-edge software, excellent administration suite and 64-bit edition. It was also the first major distribution to jump on the netbook bandwagon with out-of-the box support. Nevertheless, Mandriva has been struggling lately as a result of some controversial decisions made by its French maker. It recently restructured, with the result that some view the future of its community version as uncertain.

8. Sabayon/Gentoo

Italian Sabayon is essentially a LiveCD version of Gentoo, which is known for allowing users to individually optimize each component. Both are considered advanced Linux distributions aimed primarily at experienced users.

9. Arch Linux... plus Slackware

Arch is another package aimed primarily at experienced users interested in tweaking and optimizing their systems. Though not in the top 10 currently, Slackware is similarly oriented toward Linux gurus.

10. Puppy Linux... plus DSL

Last on Distrowatch's top 10 currently is Puppy Linux, a compact distro that's ideal for older hardware and situations where computing resources are minimal. (Damn Small Linux, incidentally, is similar.) Though it has a small footprint, Puppy is still full-featured and includes a variety of configuration and application installation wizards. The whole OS is small enough to run directly from system RAM, so applications start quickly and respond to user input instantly.

Follow Katherine Noyes on Twitter: @Noyesk.

几篇文章

http://www.xjp.cc/download/

职场

励志


Wednesday, September 1, 2010

EyeDefender – 保护视力软件

http://www.appinn.com/eyedefender/#_

视力,肯定是要从自己做起的,一刻都不能轻松,估计,我要重新配眼镜了。。。

EyeDefender 能在规定的时间后提醒你空闲片刻,已保持眼睛的适度休息。

eyedefender

当达到规定的时间后,你可以设置一张图片来欣赏,图片底下是休息倒计时。当选择提醒里面的visual training 模式即视觉训练后,EyeDefender 会用一些非常简单的画面来吸引你的注意力,以达到活动眼球的目的,很有趣。当然,还可以启动屏保或者仅仅是在任务栏给出提醒。

我已经决定让它常住内存来保护视力了。

下载(148KB): box | 来自小众软件 | mediafire | filefront | brsbox(国内) | 新浪

Sunday, August 29, 2010

开源史上最成功的八个开源产品

http://forum.jobbole.com/entry.php/179

[发表人]: [发表时间]:2010-08-24 08:32 PM (969 查看)
   就开源本身而言,它就是个成功案例。它不仅受个人喜欢,而且众多知名企业也青睐于它。
开源史上最成功的八个开源产品    伯乐在线-职场博客
   虽然开源计划和开源产品数不胜数,但哪一个才是最成功的呢?这里所说的"成功"的定义是:应用广泛+众所周知。而在众多成功的开源产品中,只有少数领头羊,而其他产品基本只能望其项背。

   Linux

   上榜理由:Linux + GNU = GNU/Linux 。从Linus Torvalds在1991年宣布他在Minix基础上创建一新OS内核到现在已经接近20年了。在这段时间内,大部分网络服务器都是Linux系统。


   BSD

   上榜理由:长久以来,FreeBSD, NetBSD和OpenBSD是服务器众操作系统之中广为人知的3个OS。上世纪90年代,三者均是脱胎于伯克利的Unix系统,故把三者组团上榜。另外,Apple的Mac OS脱胎于FreeBSD。


   MySQL

   上榜理由:MySQL是全球使用范围最广的数据库系统。2009年,全球的MySQL安装数量已达1千1百万。它是LAMP架构(Linux, Apache, MySQL, PHP)中的M。众多知名网站和产品均使用MySQL,比如:维/基百科、Facebook、Google和Wordpress。(Google和Facebook均改造了MySQL,以满足自身需求。详情可见本文末尾推荐阅读文章)。


   Apache

   上榜理由:Apache HTTP服务器从它诞生的1996年开始,它是全球使用最为广泛的Web服务器,其市场占有率远远超过第二名的IIS。2009年,全球超过1亿个网站使用Apache。

   据Netcraft2010年8月11日的数据统计表明,全球目前已有119,664,128个网站使用Apache;目前Apache市场占有率为56.06%,IIS为25.03%。
Web 服务器市场占有率    伯乐在线 - 职场博客
图1: Web 服务器市场占有率(点击图片放大查看)


   Firefox

   上榜理由:目前为止,它是Mozilla的最成功产品。2004年11月9日,FireFox 1.0问世。目前Firefox虽无法撼动IE的霸/主地位,但它是众多技术人员的首选浏览器。Firefox浏览器进化史:2002年9月23日Phoenix -> 2003年5月17日改为FireBird -> 2004年2月9日改为FireFox。

   根据Net Market Share 2010年7月份最新统计,Firefox市场占有率为22.91%,IE为60.74% 。

浏览器市场占有率     伯乐在线 - 职场博客
图2:浏览器市场占有率(点击图片放大查看)



   WordPress

   上榜理由:从2004年Wordpress作为b2博客软件一分支面世后,它开始主宰博客平台市场。据Pingdom 2009年的调查表明,全球Top 100博客中27%使用Wordpress。如果加上Wordpress.com和Automattic的Wordpress服务博客,该数据上升至32%。

   2010年8月份,Wordpress 3.0下载量已超过1250万。

   BIND

   上榜理由:BIND(Berkeley Internet Name Domain Server)是现今互联网上最常使用的DNS服务器软件,使用BIND作为服务器软件的DNS服务器约占所有DNS服务器的90%。BIND的第一个版本要追溯到20世纪80年代,它由伯克利大学的4位研究生共同开发,它和4.3 BSD一起发布。可以这样说,它就是全球的标准DNS服务器。

   不接触Linux的朋友应该很少听过BIND。因为全球大多数服务器的OS均为Linux/Unix,而这些Linux/Unix均绑捆BIND,所以BIND的份额才非常高。

   Ubuntu

   上榜理由:2004年10月20日,Ubuntu首个版本发布。迄今为止,它是Linux流传最广的分支,尤其是其出色的桌面系统。鉴于Ubuntu近些年来的巨大成功,榜上有名,应受之无愧。


   后记——无处不在的开源产品

   看到这里,你是不是发现,这8个产品中有6个在开源历史上的九个重大事件中出现过呢?其实,这也从另一个角度说明,这些开源产品对IT业界产生了重要影响。比如:Facebook背后就有非常之多的开源产品在支撑。

   我们平时上网可能不会太注意,其实这些开源产品真的是无处不在。你访问的网站,大部分是使用Apache的Web服务器;你访问的网站,大部分操作系统是Linux或BSD;你访问的网站,大部分都是使用MySQL;你提交DNS查询请求由BIND服务器分析处理;你访问的博客很可能就是Wordpress的;说不定你现在就是用Firefox在阅读伯乐在线职场博客的这篇文章。 

Thursday, August 26, 2010

Google adds phone calling to Gmail

http://voices.washingtonpost.com/fasterforward/2010/08/google_adds_google_voice_to_gm.html?wprss=fasterforward

Google's Gmail isn't just a mailbox -- it now doubles as a phone. Users of Google's Web e-mail service can now call any phone in the U.S. or Canada for free (and make international calls for almost free) from within their browser.

gmail_calling.png

Google announced this feature in a blog post a few minutes ago. It seems to be built off the voice and video chat feature Google added two years ago, as it requires installing a new version of its chat plug-in, available for Windows XP or newer, Mac OS X 10.4 or newer and some versions of Linux.

(Note that this plug-in will also install a Google software-update utility in the background, which would unnerve me more if Google hadn't released that tool's code under an open-source license last year.)

I couldn't needed a couple of tries to get this plug-in to work in Apple's Safari browser on a Mac, while in the Mac, Windows and Ubuntu Linux versions of Firefox, it worked as advertised right away, allowing me to call my work voicemail, my work phone and two cellphones. The audio quality sounded fine -- as I'd hope on a Fios connection with more than enough bandwidth for voice calling.

While it's already being described as "Google Voice integrated into Gmail," the new calling feature doesn't require an account on Google's separate calling service (only opened to the public a couple of months ago). A voice account will, however, let you answer incoming calls from within Gmail.

If you have a Gmail account, give this service a try yourself and let me know in the comments how it works for you.

By Rob Pegoraro | August 25, 2010; 1:28 PM ET
Categories: E-mail , Mobile , Telecom

Monday, August 23, 2010

图文细说Google数据中心

http://forum.jobbole.com/entry.php/173

[发表人]: [发表时间]:2010-08-19 09:41 AM (609 查看)
   2010年7月20日,Google能源部向NextEra能源公司购买1.14亿瓦的风力电能,以供部分数据中心在未来20年使用。NextEra已从7月30日开始向Google供电。
图文细说Google数据中心 伯乐在线 - 职场博客
   Google数据中心一直是业界中令人着迷的"对象"之一。那么Google到底有多少数据中心?它们分布在什么地方?伯乐在线-职场博客的这篇文章整理收集一些有趣信息,以供分享和参考。


   Google数据中心分布图

   Google 搜索速度为什么能这么快?这主要因为Google在全球分布着众多的数据中心。根据现有信息,如果包括在建的数据中心,Google共有36个数据中心。其中美国有19个、欧洲12个、俄罗斯1个、南美1个和亚洲3个(北京-Google.cn、香港-Google.com.hk和东京各1个)。不过,Google也并非完全独享这些数据中心,他们也向其他公司出租空间。

Google数据中心-全球 伯乐在线 - 职场博客
图1:Google数据中心-全球

Google数据中心-北美 伯乐在线 - 职场博客
图 2:Google数据中心-北美

Google数据中心-欧洲 伯乐在线 - 职场博客
图3:Google数据中心-欧洲



   Google的第一个"数据中心"

Google的第一个
图4:Google的第一个"数据中心"--BackRub

   Google 的首个"数据中心"是在佩恩的宿舍楼。一句话概括:麻雀虽小,五脏俱全。详细配置请看《成名之前的Google:斯坦福大学期间的Backrub原貌》


   数据中心的服务器

   大部分公司都是向Dell、HP、IBM和SUN厂商直接购买服务器。购买服务器需要一大笔费用,如果 Google的服务器均从其他公司购买,估计Google也无法有今天。时至今日,Google的所有服务器均为自己一手打造。Google服务器厚度 3.5寸,2U(两机柜式),它有2个CPU、2个硬盘,采用技嘉主板,有8个内存插槽。Google采用AMD与英特尔的x86处理器。在同样大的空间 内,Google的服务器比其他厂商的服务器能容纳更多的CPU。

Google服务器 伯乐在线-职场博客
图5-1:Google服务器

谷歌的一组服务器 伯乐在线 - 职场博客
图5-2:"世纪互联"机房中谷歌的一组服务器(DELL Precision 390 工作站)

   数据中心以集装箱为单位,每个集装箱里面有1160台服务器,每个数据 中心有众多集装箱。



   数据中心的核心技术

   Google一直都钟情于开源软件,也一直支持开源技术 (Google对手之一的Facebook也同样重视开源技术)。Google服务器使用的是Linux操作系统。Google的工程师按照平行计算的要 求对Linux进行了优化。Google开发自有核心软件,开发语言是Java和C++。

   Google的三大核心元素:
  1. Google 文件系统(GFS);(GFS负责服务器数据储存工作)
  2. Google大表;Bigtable:是Google一种对于半结构化数据进行 分布存储与访问的接口或服务);由于Google的文件系统异常庞大,以至于甲骨文和IBM公司的商业数据库在方面无用武之地。另外,商业数据库都是按 CPU数量来收费,如果Google使用商业数据库,可想而知,这是一笔天文数字。所以,Google量体裁衣地设计了符合自身的大表。
  3. Mapreduce 算法;它是Google开发的C++编程工具,用于大于1TB数据的大规模数据集并行运算。MapReduce能够找出一个词语在Google搜索目录中 出现的次数;一系列网页中特定词语出现的频率;链接到某个特定网站的所有网站数量等。
   虽然Google依靠许多开源项目实现了企业的腾飞,但Google始终对这三大核心元素保密。



   数据中心的专利
  1. 服务器内置电池。 每台服务器都有一颗12伏特电,确保万一主断源断电时还可持续供电。最终目的,节约成本。
  2. 可移动的数据中心集装箱。2008年10月获得该项专利,每个集装箱中最多可容纳1160台服务器。

   数据中心的开销

   根据Google的盈利报告,2006年Google在数据中心上的开销是19亿美元,2007年是24 亿,2008年23.6亿,2009年8亿9百万,2010年上半年已开销7亿1千5百万。

Google数据中心
图7:Google数据中心"烧钱"曲线图


   数据中心的选址标准
  1. 大量的廉价电力;
  2. 绿色能源,更注重可再生能源;
  3. 靠近河流或湖泊;(设备冷却需要大量水源)
  4. 用地广阔;(隐秘性和安全性)
  5. 和其他数据中心的距离;(数据中心之间的快速链接)
  6. 税收优惠。

Google数据中心 伯乐在线 - 职场博客
图8:Google的服务器(左)Google俄勒冈州Dalles数据中心(中)Google 服务器机柜特写(右)


   Google的特殊数据中心——圣吉兰数据中心

   Google在比利时的圣吉兰(Saint Ghislain)数据中心(图3中编号26)根本没有冷却装置,完全依靠纯自然冷却(即:用数据中心外面的新鲜空气来支持冷却系统)。一般来说,绝大部分数据中心都是采用水冷却装置。(这也就是为什么数据中心选址时要考虑水源。)

Google比利时数据中心 伯乐在线 - 职场博客
图9:Google比利时数据中心

比利时国王参观Google比利时数据中心 伯乐在线 - 职场博客
图10:比利时国王(左五)参观Google比利时数据中心



   Google的Dalles(达尔斯)数据中心

   Dalles数据中心(图2中编号8)位于俄勒冈州的波特兰以东约80英里,旁边是哥伦比亚河,河上有座大坝——Dalles大坝,大坝为数据中心提供便宜的电力。数据中心有2座4层楼高的冷却塔。(注:"Dalles"不是"Dallas",Dallas达拉斯在德州。)

Dalles数据中心鸟瞰图 伯乐在线-职场博客
图11:Dalles数据中心鸟瞰图
   以下这段话来自Nicholasg Carr,他曾经在2009年访问Dalles数据中。蓝色部分是关关的注释。

   Dalles数据中心有3个超大机房(在图11中有4个白色建筑,但只有3个是服务器机房),每个机房有45个集装箱,每个集装箱可以放置1160台服务器,故Dalles数据中心可以存放约15万台服务器。



   Google的秘密

   Google在其数据中心的位置和数量方面的保密工作做得很好。比如说:如果你反查Google各种爬虫或者是Google各个域名的IP地址,所得结果几乎看起来都是加州山景城的IP地址。因此,想通过反查IP地址,基本无法推断出其数据中心的真正位置和真正数量。

   此外,Google通常把其数据中心"伪装"成有限责任公司, 表明上看起来和Google毫无瓜葛。比如:北卡罗来纳州Lapis公司和爱荷华州的Tetra公司。

   既然Google在其数据中心方面的保密工作做得很出色,所以本文的信息未必是百分百正确。



   其他相关旧闻

   2008年1月28日有报道称,Google将在TW建立一数据中心。TW经济负责人陈瑞隆已确认此消息,并且表示已在TW西部彰化的彰滨工业区内为Google预算了一块地。TW还将向 Google提供各种优待,包括土地税折扣、保证电力供应稳定在内。不过至今一直没有听到这个数据中心在台的任何动静。

   在陈瑞隆确认消息 后的第二天,马来西亚总理也宣布,Google有意在马来西亚建立数据中心。

   另据报道,Google有意在东欧的立陶宛新建数据中心。

   另外,Google曾于2007年在南卡罗来纳州的布利西伍德购买466英亩(1英亩约合4000平方米)土地,似乎是打算建立南卡的第二个数据中心。

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Thursday, August 19, 2010

Edit hosts file in Windows 7 & Windows Vista

The host file is the one where one enters hostname and IP Address pair manually as against being served by a Name server (ex: DNS). As always the "host" file is under C:\windows\system32\drivers\etc\

To edit the host file, Click Start – search for "Notepad", right-click and select "Run as Administrator". This should launch notepad with elevated privileges. Now, open the host file from the File menu, edit and save.

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