Distributed Computing

我国在最晚不晚于宋代发明了水密隔舱。所谓水密隔舱，是指将船体分成若干个互不相通的舱区，这样当一个或几个舱区进水时，整个船体仍然可以有足够的浮力而不致沉没。这是一项相当重要的发明，类似的设计思路在其他领域也有应用。

和蛇头GG讨论了一个关于卖票的问题，简单地说是票很有限，需求量很大，如何能够尽可能高效地让票以尽可能公平的方式卖出去。

我设计了一个分布式的结构来解决这个问题，当然这个原型可以进一步改进，此处按下不表。记录一下我对这个结构公平性的描述的一个比喻：

Today I have some ideas about P2P application framework. Would check if there is any available ones and whether they can fulfil my ideas. Maybe I would start a project to implement these ideas in Python and/or C++.

在火车上跟HD聊了聊关于GNS等等一系列项目的想法。所谓GNS是一个全局的目录服务，包括客户和服务器两部分，客户运行在提供各种不同服务的机器上(www, databases, etc)。

客户启动时，向服务器发出一个「WAKEUP」信号，服务器则向需要该服务的所有服务器发出同样信号；反之，当客户所在的机器准备下线时，也类似地发出信号。

www, databases等服务的consumer据此在自己的本地可用服务表中添加/删除目录项。

Sprite is a research operating system developed at the University of California, Berkeley, by John Ousterhout’s research group.

Sprite is a distributed operating system that provides a single system image to a cluster of workstations. It provides very high file system performance through client and server caching. It has process migration to take advantage of idle machines. It was used as a testbed for research in log-structured file systems, striped file systems, crash recovery, and RAID file systems, among other things.

As announced in 20040429163636.911BB114DF@beastie.frontfree.net, we finally, have to accept the fact that pyxis_gk is leaving the development team due to lack of time and interest.

An interesting conversation in FreeBSDChina’s core:

delphij -> yarshure: I need some help on qmail
yarshure -> delphij: alu is qmail guru
delphij (continue the conversation with alu and finally solved the problem)

The idea of our (Grid Distribute) access control’s design is somewhat simple one. To maintain maximum security, it turns out that we must keep the directory highly consistent, to prevent ACL distribution problems.

The “Distribution Set” is an important idea on GridDistribute’s vendor distribution. Here comes different ideas on implementing it, which will influence the search approach we will choose. Personally, I think we must have a final decision before next Wednesday.

This is a complex problem. A peer to peer system consists many self-determinating nodes is hard to control, and when it goes crazy, it will be easy to launch a distributed denial-of-service (DDoS) attack.

Here are some of my thoughts, well, they are not mature and some of them might be misleading, but I will write them here.