来自http://fengnet.com/book/voip/ch13lev1sec4.html

This section illustrates a few typical call flows with an explanation of the semantics of each message. The call flows are presented in order of increasing complexity. Note that the call flows presented here are shown as an example for illustration purposes. An implementation for a particular vendor of MGCP might follow a different call flow.

Basic MGCP Call Flow

A simple point-to-point call is set up using two different commands: CreateConnection and ModifyConnection.

Figure 13-2 shows a call flow for a call setup between two endpoints. The endpoints are assumed to be on different gateways, and the MGC controls both the gateways. Only the relevant portions of the messages are shown in the figure. The originating side and a terminating side of this two-party call are labeled with suffixes Orig and Term, respectively. Messages in the figure are labeled numerically, and the corresponding label is referenced in the explanation that follows. Of course, the labels are not part of the MGCP messages.

Figure 13-2. Basic MGCP Call Flow

1. The call agent sends an initial CRCX to the GW-Orig and specifies endpoint S1/DS1-0/1. The connection mode is set to recvonly. This setting indicates to the GW-Orig that the endpoint should receive media from the IP network but not send media to the IP network. This is necessary because the call agent has not set up the connection on GW-Term and hence does not know the session description at that end.

2. GW-Orig responds with a 200/OK indicating that the connection was created successfully and providing a local session description (encoded per SDP specification). This session description includes the local IP and port (1.1.1.1 and 11111) that the gateway has opened to receive RTP streams. SDP also indicates that the codec being used is G.711µ-law (denoted by RTP/AVP 0).

3. The call agent then sends a CRCX to endpoint S1/DS1-0/1 on GW-Term. The session description received from GW-Orig is included in the RemoteConnectionDescriptor of this CRCX, and the mode is set to sendrecv.

4. GW-Term responds with a 200/OK and includes its own session description in the response.

5. The call agent passes the SDP of GW-Term to GW-Orig in a MDCX command and changes the connection mode to sendrecv.

6. After GW-Orig executes the MDCX command and responds with 200/OK, call setup is complete and RTP streams flow between GW-Orig and GW-Term.

Trunking GW-to-Trunking GW Call Flow

The call flow discussed in the preceding section showed you that setting up connections using MGCP is fairly straightforward. However, the call flow does not tell you how and why the call agent decided to set up the connection between those two endpoints. In real life, the call agent learns about this from external signaling. A typical example is an SS7 trunk terminating on the call agent. In such a case, the SS7 messages trigger the actions of the call agent.

Figure 13-3 shows the interaction between SS7 messages and MGCP.

Figure 13-3. Trunking GW-to-Trunking GW Call Flow

An initial address message (IAM) [1] comes in to the call agent on an SS7 trunk. This action triggers the call agent to analyze the IAM and decide how to handle it by consulting its local configuration. The local configuration (or an external database lookup) tells the call agent to set up a call between the two endpoints ep-orig and ep-term on the gateways GW-Orig and GW-Term.

The call agent sends two CreateConnection messages [2] and [4] that are similar to the call flow illustrated in Figure 13-2. After PSTN-term seizes the line, it sends an SS7 ACM [7] message to the call agent. Then the call agent sends an MDCX [8] to GW-Orig. Notice that the ConnectionMode is now set to recvonly. This is because, at this point, only the ringing tone needs to flow back to the originating side. The originating side cannot send audio yet.

After the terminating phone is picked up, PSTN-Term sends an ANM [11] message to the call agent. This triggers the call agent to send an MDCX to GW-Orig setting the mode to sendrecv. This completes the setup of gateways for two-way audio.

说“日子是一天一天过的”，没错！
不过，这是一个绝对的概念，来看看相对的概念是啥样的。

你是不是经常感觉一星期一晃就过去了？
有时候到月底一看，哦，一个月又过去了？
还有，好像过完年没多久，日历却已经快翻到10月份，下一个春节又在眼前。

当我回顾了一下人生经历，才发觉这日子过得，还没明白什么，“而立”后又有了不少日子。

有时，伫立在某个时间点，才知道时间流逝很快。
似乎在时间隧道中，看着世事变迁，人来人往，时间过去了，而人，还站在原地。
造物主赋予我们时间的同时，却用一个倒计时表将时间一点点地拿走。

在有限长度的时间隧道里，
我可以当做什么都没有发生，也可以看着别人的故事无动于衷。
但我想，
人可以轻轻地来，
却不能不带走一片云彩地离开。

也许
在某一天
你能在你的时间隧道中
看到某一人
在云中漫步……

——不切实际的题目，不切实际的结尾 于A

一个时间周期后，比如一年、五年、十年……后，你的人在哪里？你的心在哪里？你的情归何处？
再回想，一个时间周期前，比如一年、五年、十年……前，你的人在哪里？你的心在哪里？你的情又在哪里？

——童年、青春、世故，人生的三部曲 于北京家

Linux文件查找命令find,xargs详述

下面段落摘自RFC3265，是对服务器直接发出NOTIFY消息的一个解释。一般情况下，在NOTIFY消息前会有SUBSCRIBE消息。

3.2. Description of NOTIFY Behavior   NOTIFY messages are sent to inform subscribers of changes in state to
   which the subscriber has a subscription.  Subscriptions are typically
   put in place using the SUBSCRIBE method; however, it is possible that
   other means have been used.

   If any non-SUBSCRIBE mechanisms are defined to create subscriptions,
   it is the responsibility of the parties defining those mechanisms to
   ensure that correlation of a NOTIFY message to the corresponding
   subscription is possible.  Designers of such mechanisms are also
   warned to make a distinction between sending a NOTIFY message to a
   subscriber who is aware of the subscription, and sending a NOTIFY
   message to an unsuspecting node.  The latter behavior is invalid, and
   MUST receive a "481 Subscription does not exist" response (unless
   some other 400- or 500-class error code is more applicable), as
   described in section 3.2.4.  In other words, knowledge of a
   subscription must exist in both the subscriber and the notifier to be
   valid, even if installed via a non-SUBSCRIBE mechanism.

   A NOTIFY does not terminate its corresponding subscription; in other
   words, a single SUBSCRIBE request may trigger several NOTIFY
   requests.

作为一个大国的执政党是不容易的。
中国有句古话叫做，“众口铄金，积毁销骨”。
也许东西并不好，好话听多了，大家都被蒙蔽了。
也许东西是好东西，但坏话听多了，大家也被骗了。
有时候，好话坏话说多了，都不好。
在这个建国60年即将到来的日子，听到越来越多共产党的颂歌。
心里有个想法，颂歌是别人歌颂自己的，可是怎么很少听到其它国家的声音，至少亚非拉各国应该有些动静吧？
我是感觉自己给自己唱颂歌是不是有些寂寞？难道又回到过去朝代更替的日子，成天给帝王歌功颂德？

老百姓都知道，“王婆卖瓜，自卖自夸”，是贬义的。
自己闷头做事，有成绩也是领导的，没人会想到表扬你。
还记得吗？以前有多少农村教师、打工仔辛辛苦苦地做工，过了几十年，连个国家承认的身份都没有？到头来一家人跟着受罪。
可一旦被树立成为典型，要啥给啥，用“一人得道鸡犬升天”形容也不为过，虽然这也是看客的“酸葡萄”心理。
根儿上呢，还是公权力没有保障个人的权益，制度上执行或者监管出了问题。
这就会导致“会叫的鸟儿有食吃”，逼着人们“自卖自夸”，甚至没资本也夸，然后浮夸成风。
这不，就这两天，刚刚全国大面积干旱洪水报道才过去，又说今年粮食大丰收。
跟我以前写的一篇文章中的猜测联系起来，前几年的收成，不是浮夸，就是地方报少了，自己密下来，到了收成不好的年月就拿出来应付上级。
不然，也不会说，全国耕地降到16亿亩还能比前一年收得更多。
还有几年前全国范围出现的国储粮“老鼠仓”事件从侧面说明数据是有水分的。
从另一个角度来看，浮夸是因为“上梁不正”。
刚才说到16亿亩耕地红线，就要感叹了，“不怕没好事，就怕没好人”。
“非著名经济学家”茅于轼在美国福特基金会的支持下提出粮食问题由市场经济解决，舆论可以说一片哗然。
最近虽然他也没什么动静了，不过又有人把房价跟“丈母娘的需求”联系起来，说这话的人还是业内的专家，也被人批得体无完肤。

“你说我共产党容易吗？”
治理这么大个国家，有5000年历史的国家，是不容易。
外面国家都一门心思防着你，逮个机会挖一下社会主义墙角。
内部呢，还有这么些个所谓的专家、智囊，拿着不知道哪个大学的文凭，做着“双面间谍”的勾当。
国家培养的专家都成了利益团体的代言人。
科研机构还是象牙塔吗？怎么成了间谍培训班？

这个世界太险恶了，谁都要防着点儿？
看看我们是怎么建立这个国家的吧。
刚解放那阵子，比现在的中东欧国家匈牙利还厉害，简直就是各国间谍的竞技场。
６０年后，从人人自危的环境到富足的生活条件，要是不从个人得失的角度来说，你看执政党容易吗？难道你能做到？
一个党好不好，看看历史就知道了。
世界上都没有完人，为什么还要求一个完美的政党？

虽然我对经常“自卖自夸”的印象不好，但我想将来没有哪个政党能够让中国更加强大、中国人生活更好，除了共产党。
因为共产党做到了让普通中国人不受歧视地生活，有尊严地生活，也做到了自己承诺的事情。
尽管也曾有反复，不过长期来看的确做到了。
政治和民主是不能原封不动地引进来的，那些颜色革命的国家，老百姓的生活又咋样了？

来自外国的思想在中国落地生根，变作中国化的道路，在中国人的包容下，让世界另眼相看。
无法想象如果中国人都像外国人对执政党那么苛刻，中国还能有机会发展起来吗？
所以很多事情都是相互的，只要别忘了本，水就不会覆舟。

将来的事情，将来做，但现在最好想明白。

我知道我一定会忘记
所以昨夜我将一颗种子种下
在记忆的伊甸园里
在也许并不存在的媒体上
用关键词做标记
用神谕做指引
期待某天能收获一把钥匙
打开通往心灵的大门
重温以往消失在岁月的记忆

当我开始妥协，不是我的错，而是人很脆弱。

RFC文档是网络和通信行业的宝典，今天看的时候有点体会。都说做事前需要计划，但其实这句话是很虚的。在每个行业、做每件事情前不是做计划，而是学习，而且还不是学一时，搞不好是学一辈子。
很多的RFC文档都会引用这个文档，Key words for use in RFCs to Indicate Requirement Levels。在我看来，需求是产品开发中最难的一个环节。有这样的一个文档，来将模棱两可的主观判断尽量统一。这样大家会有类似的标准来进行协作。下面是这个文档的内容，我们在工作中也可以借用一下它的思想方法。 A



BEST CURRENT PRACTICE
Errata

Network Working Group                                         S. Bradner
Request for Comments: 2119                            Harvard University
BCP: 14                                                       March 1997
Category: Best Current Practice


        
Key words for use in RFCs to Indicate Requirement Levels

Status of this Memo

   This document specifies an Internet Best Current Practices for the
   Internet Community, and requests discussion and suggestions for
   improvements.  Distribution of this memo is unlimited.

Abstract

   In many standards track documents several words are used to signify
   the requirements in the specification.  These words are often
   capitalized.  This document defines these words as they should be
   interpreted in IETF documents.  Authors who follow these guidelines
   should incorporate this phrase near the beginning of their document:

      The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL
      NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED",  "MAY", and
      "OPTIONAL" in this document are to be interpreted as described in
      RFC 2119.

   Note that the force of these words is modified by the requirement
   level of the document in which they are used.

1. MUST   This word, or the terms "REQUIRED" or "SHALL", mean that the
   definition is an absolute requirement of the specification.

2. MUST NOT   This phrase, or the phrase "SHALL NOT", mean that the
   definition is an absolute prohibition of the specification.

3. SHOULD   This word, or the adjective "RECOMMENDED", mean that there
   may exist valid reasons in particular circumstances to ignore a
   particular item, but the full implications must be understood and
   carefully weighed before choosing a different course.

4. SHOULD NOT   This phrase, or the phrase "NOT RECOMMENDED" mean that
   there may exist valid reasons in particular circumstances when the
   particular behavior is acceptable or even useful, but the full
   implications should be understood and the case carefully weighed
   before implementing any behavior described with this label.





Bradner                  Best Current Practice                  [Page 1]

 
RFC 2119                     RFC Key Words                    March 1997


5. MAY   This word, or the adjective "OPTIONAL", mean that an item is
   truly optional.  One vendor may choose to include the item because a
   particular marketplace requires it or because the vendor feels that
   it enhances the product while another vendor may omit the same item.
   An implementation which does not include a particular option MUST be
   prepared to interoperate with another implementation which does
   include the option, though perhaps with reduced functionality. In the
   same vein an implementation which does include a particular option
   MUST be prepared to interoperate with another implementation which
   does not include the option (except, of course, for the feature the
   option provides.)

6. Guidance in the use of these Imperatives

   Imperatives of the type defined in this memo must be used with care
   and sparingly.  In particular, they MUST only be used where it is
   actually required for interoperation or to limit behavior which has
   potential for causing harm (e.g., limiting retransmisssions)  For
   example, they must not be used to try to impose a particular method
   on implementors where the method is not required for
   interoperability.

7. Security Considerations

   These terms are frequently used to specify behavior with security
   implications.  The effects on security of not implementing a MUST or
   SHOULD, or doing something the specification says MUST NOT or SHOULD
   NOT be done may be very subtle. Document authors should take the time
   to elaborate the security implications of not following
   recommendations or requirements as most implementors will not have
   had the benefit of the experience and discussion that produced the
   specification.

8. Acknowledgments

   The definitions of these terms are an amalgam of definitions taken
   from a number of RFCs.  In addition, suggestions have been
   incorporated from a number of people including Robert Ullmann, Thomas
   Narten, Neal McBurnett, and Robert Elz.












Bradner                  Best Current Practice                  [Page 2]

 
RFC 2119                     RFC Key Words                    March 1997


9. Author's Address

      Scott Bradner
      Harvard University
      1350 Mass. Ave.
      Cambridge, MA 02138

      phone - +1 617 495 3864

      email - sob@harvard.edu

昨天从凤凰网上看到个评论，标题是“良善之人，虎狼之心”。
我想，残酷的世界让我选择面对现实，但现实的想法是为了自我完善，而不是更加现实。

——也许现阶段的我还不够现实吧 A

　　这首诗来自于泰戈尔的《飞鸟集》
　　《飞鸟集》有点类似于语录体的文集

　　世界以它的痛苦同我接吻，而要求歌声做报酬。
　　The world has kissed my soul with its pain, asking for its return in songs.

http://news.ifeng.com/opinion/society/200909/0924_6439_1362197.shtml

10年前在从拉萨飞回北京的飞机上，我的身边坐了一个50多岁的女人，她是30年前去援藏的，这是她第一次因为治病要离开拉萨。下了飞机下很大的 雨，我把她送到了北京一个旅店里。过了一个星期我去看她，她说她的病已经确诊了，是胃癌晚期，然后她指了一下床头有一个箱子，她说如果我回不去的话，你帮我保存这个。这是她30年当中走遍西藏各地，和各种人交谈的记录。这个人姓雄，拉萨一中的女教师。

5年前，我采访了一个人，这个人在火车上买了一瓶1.5元的水，然后他问列车员要发票，列车员乐了，说我们火车上自古就没有发票。这个人就把铁道部告上了法庭。他说人们在强大的力量面前总是选择服从，但是今天如果我们放弃了1.5元的发票，明天我们就可能被迫放弃我们的土地权、财产权和生命的安全。权利如果不用来争取的话，就只是一张纸。他后来赢了一场官司，我以为他会和铁道部结下“梁子”，结果他上了火车之后，在餐车要了一份饭，列车长亲自把这个 饭菜端到他面前说，“您是现在要发票还是吃完以后我再给您送过来？”我问他，你靠什么赢得尊重？他说我靠为我的权利所做的斗争。这个人叫郝劲松，34岁的律师。

去年我认识一个人，我们在一起吃饭，这个60多岁的男人说起丰台区一所民工小学被拆迁的事，他说所有的孩子靠在墙上哭。说到这儿的时候，他从裤兜里面掏出一块皱巴巴的手绢，擦擦眼鼻。这个人18岁的时候当大队的出纳，后来当教授，当官员，他说他所有做这些事的目的只是为了想给农民做点事。他在我的采访中说，征地问题给农民的不是价格，只是补偿，这个分配机制极不合理，这个问题的根源不仅出在土地管理法，还出在1982年的宪法修正案。审这个节目时，我的领导说了一句话，这个人就说得再尖锐，我们也能播。我说为什么？他说因为他特别真诚。这个人叫陈锡文，中央财经领导小组办公室主任。

7年前，我问过一个老人，我说你的一生已经有过很多挫折，你靠什么保持你年轻时候的情怀？他跟我讲有一年他去河北视察，没有走当地安排的路线，在路 边发现了一个老农民，旁边放着一副棺材，他下车去看，那个老农民说因为太穷了，没钱治病，就把自己的棺材板拿出来卖。这个老人就给了他500元钱拿回家。他说我讲这个故事给你听，是要告诉你，中国大地上的事情是无穷无尽的，不要在乎一时的得失，要执著。这个人叫温家宝，中华人民共和国总理。

一个国家是由一个个具体的人构成的，它由这些人创造并且决定，只有一个国家能够拥有那些寻求真理的人，能够独立思考的人，能够记录真实的人，能够不计利害为这片土地付出的人，能够捍卫自己宪法权利的人，能够知道世界并不完美，但仍然不言法理、不言放弃的人，只有一个国家拥有这样的头脑和灵魂，我们才能说我们为祖国骄傲，只有一个国家能够尊重这样的头脑和灵魂，我们才能说，我们有信心让明天更好。（原题：身边的人）

SIP呼叫的发起方和接收方各自维护CSeq号码。

Beijing may allow the yuan to appreciate in the second half of 2010 in order to keep up with currencies in other markets including South Africa and Indonesia, Bloomberg reported, citing J.P.Morgan's Chief Asian Strategist Adrian Mowat. In the last six months of next year the base effect on inflation and commodity prices will look a lot less favorable, Mowat said. He believes there might be an incentive for China to allow the currency to appreciate in order to manage inflation without raising domestic interest rates. Mowat earlier cut J.P.Morgan's rating on China to "underweight" from "neutral," advising emerging-market money managers to focus on South Africa and Thailand as the recovery of their economies will accelerate later this year, extending gains in their respective currencies.

SIP中的一些字段，特别是关于路由的字段是非常容易搞混的。比如：
Route
Record-Route
Path
Via
Service-Route
Contact

Route指向消息的下一跳。
Record-Route告诉后面的服务器，以后回复消息一定要再经过我。比如说，服务器A在发送的消息里加上了Record-Route，那么接收到这个SIP消息的服务器会将后续的回复转发给服务器A。

以后再补充其它的消息头的作用。

参见SIP流程http://www.ietf.org/rfc/rfc3665.txt

A

这个系列是关于3GPP标准中IMS Core的信令交互，本着看到哪里写到哪里的原则，一点一点积累，主要是作为个人的一个速查手册使用。

这部分关于Cx接口：

在用户注册的时候，I-CSCF使用UAR命令从数据库中找到S-CSCF的地址。
如果I-CSCF接收到的消息不是REGISTER，如INVITE消息，那么I-CSCF将使用LIR命令来找到S-CSCF的地址。

  来自Black Duck Software的统计数据显示，GPLv2（Genaral Public License， version 2）的流行度正在下降。Black Duck Software是软件资源方面的专家，它在自己的主页上 的每日数据里更新了关于最流行20款开源许可证的统计数据。所依据的数据来自内部知识库，这些信息来自大概185，000个软件项目。统计数据显示最新的 版本有49.5%的用户在使用，也就是有大约100，000项目使用了GPLv2。

在 2008年六月，这个著名的许可证使用率曾经一度达到过57.7%， 现在，GPLv2仍然是毋庸置疑的领导者。紧随第二位的是Lesser General Public License（LGPL），使用比例为9.5%。Perl Artistic License排在第三位，GPLv3以5.3%的占有率排在了第五，而LGPLv3排在15。

GPL版本之间的竞争特别让人心酸。Linus Torvalds强烈反对严格的版本，并且反复强调Linux内核将继续采用GPLv2。GPLv3在2007年七月的时候发布，它的上一个版本则发布于 1991年。LGPL是在Richard Stallman的领导下由自由软件基金会开发，是AGPL的网络变种。

　　Black Duck的主席Eran Strod在他的解说词中，大大赞扬了基金会的功绩，但没有提及版本冲突的情况。“对于任何对开源有激情的人，我都不能完全说清楚自由软件基金会它那不可 思议的贡献，它让整个业界和世界都来创造GPL许可证系列。”据Black Duck Software统计数据，现在的开源许可证数量有1698种。

赛迪网讯 9月21日消息，据国外媒体报道，美国投资研究公司Sanford Bernstein分析师托尼·萨柯纳吉(ToniSacconaghi)认为，为实现15亿美元的运营利润增长，甲骨文或对Sun裁员50%。

　　8月底，Sun发布了2009财年第四财季财报，Sun亏损1.47亿美元，营收同比下跌31%。这使得甲骨文通过收购Sun来提升15亿美元运营利润的希望几乎不可能实现。

　　但是，甲骨文在上周发布财报时仍表示，对增加15亿美元的运营利润充满信心。对此，萨柯纳吉认为，除非甲骨文对Sun裁员50%，即1.5万人，否则不可能实现该目标。

　　今年4月，甲骨文宣布以74亿美元收购Sun。甲骨文当时在一份声明中称：“在交易完成后的第一年，公司每股摊薄收益将增加15美分，运营利润将增加15亿美元，第二年的运营利润将增加20亿美元。”

　　此外，欧盟本月初已经对甲骨文收购Sun交易展开调查。在未来90天内，欧盟将对这笔交易进行仔细评估，直至2010年1月19日。这意味着在未来2个季度内，Sun仍将作为一家独立的公司继续发布着可怜的财报结果，进一步增加甲骨文实现该目标的难度。

I wrote this by a lightening. Please follow me to go into another circle. Here we go.

Can you imagine that there is another way to access internet?
I mean in another way for us to input the address of web sites?
Everybody knows internet comes from US.
And the way of thinking is based on the culture of America, in fact, western world.
Just now when I saw the CCTV website on TV, www.cctv.com, an idea came out immediately: could that be possible to use chinese words to access the big network?
Bingo! I think it is reasonable and absolutely possible.
So the problems may be how to persuade people to use the new way which is designed by chinese and can be understood easily by chinese as well.
Do you remember when we got in touch with the World Wide Web at the first time?
World Wide Web, in short, is WWW.
Literally for the sake of the difference of the culture of eastern and western, the term WWW is not understood and translated clearly.
First we studied what is URL, i.e. the address to identify the web sites.
We learned what the format of URL is, and how the web site and network extract the information from client and resolve the information to get the accessing requests to where it should be.
Then user can get rich services and the network provider can get money back.
Maybe, it is totally same way to operate when we use chinese web address, but how to get the point and how to define what the point is, should be another thing.
It is kind of scope related to localization and culture.
People should have the right to choose their accormodated way to express and accept.
So people should have another way to input what they want to look at the web, the way which is designed and maintained by native chinese.
But how to implement is a big issue for us chinese. I have to admit that chinese culture is a sort of obsorving not practicing.
We've got many thoughts but not implemented.
At old times, We've got pressue from external world which transformed our ideas into dreadful weapons.
Almost at the same time, the government slept in the warmful kindle to wait for surrounding countries to worship and give in.
I'm wondering, could that happen all the time, no pay but always gain?
Since that, we must do something different if we wanna make a difference.
Do think some doable things, not unliable thoughts.

--Take action to think now, then think how to take action later.

　　从意大利卡拉拉山上一块巨大的大理石到世界最标准身材比例的“大卫”要多长时间？
　　答案是３０年。
　　当时的市政厅邀请艺术家将卡拉拉大理石矿开采的巨石进行雕刻创作的时候，由于无人应征，这块巨石从开采后一直被遗弃了２５年。２５年后一个２６岁的年轻雕刻家接受了这个艰巨的任务，在很多人看来，几乎也是不可能完成的。这个年轻人就是米开朗基罗。
　　４年后，圣经中的人物——“大卫”，诞生了。
　　这个故事发生在５００年前的意大利文艺复兴时期。艺术是没有国界的。意大利的文艺复兴更是全世界的财富。至今我们不仅仅仍然为大师们的作品所震撼，而且社会一遍遍地在重复着一个个“大卫”等待米开朗基罗的故事，因为经典需要经过时间的沉淀，是值得期待的。
　　想成为米开朗基罗，先找到自己的“大卫”吧。
　　如果给“大卫”赋予灵魂，３０年的等待，“大卫”在那之后的５００年经久不衰。
　　从另一个角度来看，如果想成为“大卫”，先给自己物色好“米开朗基罗”吧。
　　正是这么多“如果”使生活充满不确定性，难道生活不是因为未知而吸引人吗？
　　选择是做在当下，所以选择也是一个礼物（present）。
　　多给自己几个选择，多些惊喜留给自己。

——今天我会选择什么？

《大卫》原是一块废弃的大理石

http://news.sina.com.cn/w/2004-10-11/08153874585s.shtml
《大卫》原是一块废弃的大理石

　　【新华社供本报特稿】传世雕塑精品《大卫》，因其人神合一的超凡气质举世闻名。而“大卫”健美挺拔的躯体，也成为雕塑大师米开朗基罗艺术经典范式。《大卫》在500岁的庆典之际，再次成为世人瞩目的对象。9日，在一个为期2天的艺术史研讨会上，众多知名专家纷纷提出了对这部杰作的最新发现。除了一些意大利专家担心“大卫”纤细的脚踝是否能够继续承受雕刻的捶重外，医学专家的见解更为独特。

　　出席会议的马西莫·古利萨诺是佛罗伦萨大学的解剖学教授，他与该校的血液学教授彼得 罗·贝尔纳贝合作，借助电脑等先进设备的分析，有了最新发现。他们认为，尽管“大卫”身高达到4.1米，但是手和脚的尺寸却相当匹配。不过，“大卫”后背 右侧竟然有一片挖空，以医学人体常规数据来看，这里缺少一块重要的肌肉。

　　尽管如此，古利萨诺认为，从解剖学的角度，完全可以给米开朗基罗打A＋。“他对人体构造了如指掌”，古利萨诺在接受美联社电话采访时说，曾有传言，米开朗基罗研究了太多死尸，他因此染病身亡。

　　小小的纰漏，专家没有放过。经过多方探寻，古利萨诺二人从米开朗基罗的书信中找到了答案。

　　在信中，大师已经意识到这个微小的错误。无奈，“大卫”的取材源自一个奇形怪状、有 过多凹陷的废弃的大理石，使米开朗基罗只能被迫遗漏这块肌肉。据了解，这块浑石曾经转诸多雕刻家之手，都以失败告终。但米开朗基罗却从中找到了创作灵感， 凭借超群的艺术天分，精心构思雕琢，把顽石孕育成伟大的作品。