一个案例就是关于GPL兼容的问题。Zigbee的license和GPL等很多开源协议有冲突,这个问题经过协会的board讨论后,结论是Zigbee没有做出任何妥协。我猜测原因就是会员费基本是这个标准最大的收入来源,所以不能妥协。所以冲突的那条就是:商业用途的Zigbee软件是要收会员费的(每年3500刀)。不知道这个会员费是按什么计算到了,如果Linux集成了这个协议栈进去,到底会收谁的钱?就这样通向物联网的大门几乎可以说是Zigbee自己关闭的。最近 Google Brillo,华为LiteOS还有更多的厂家纷纷推出了针对物联网的操作系统,大部分还是基于Linux和其他开源平台的,可以说封闭起来的Zigbee慢慢的缩小了自己通往成功的道路。
TCP/IP协议的设计并不是以实时通讯为基础所设计的。当我们点击desiyi.com上的链接的时候,并不能知道服务器什么时候能给出反应。在TCP/IP协议栈上,从链路层,IP层,TCP层到应用层,都没有太多考虑实时通讯。即便是后来考虑到实时数据传输(RTP),以及QoS(Quality of Service)管理中,TCP/IP也只能保证“尽可能”的让数据传输的实时性得到保证。所以,为了实现实时通讯这个工业通讯的第一要求,工业界不得不改造已经存在多年的以太网标准,从底层开始对协议进行修正来保证连接到这个网络的几千个设备能够高效的实时交换数据。而以往的现场总线中节点的数量则不过是几百个。
目前,工业以太网已经不是以前PROFIBUS那样神秘的通讯协议了。我们在电视、新闻上看到的关于“物联网(Internet of Thing)”的报道,其实来就包含了工业以太网。只不过“物联网”的含义更加宽泛,不仅工业设备要联网,连家里的家电,农业机械,楼宇设备都要联起来。工业界的西门子,罗克韦尔分别开发了自己的工业以太网标准和设备。后起的通用电气公司通过挖掘硅谷IT人力资源的方式,组建了一个400人的团队进行这方面的研发。IBM的“智慧地球”项目算是一个概念,而网络巨头思科和高通更是早早就提出了“Internet of Everything”的理念,并大力开始推进实施。所有的工业巨头都意识到互联网的革命将改变工业格局,只是他们没有想好怎么来一起进行这场伟大的变革。
And love is not the easy thing
The only baggage you can bring…
And love is not the easy thing…
The only baggage you can bring
Is all that you can’t leave behind
And if the darkness is to keep us apart
And if the daylight feels like it’s a long way off
And if your glass heart should crack
And for a second you turn back
Oh no, be strong
Walk on, walk on
What you got, they can’t steal it
No they can’t even feel it
Walk on, walk on
Stay safe tonight…
You’re packing a suitcase for a place none of us has been
A place that has to be believed to be seen
You could have flown away
A singing bird in an open cage
Who will only fly, only fly for freedom
Walk on, walk on
What you got they can’t deny it
Can’t sell it or buy it
Walk on, walk on
Stay safe tonight
And I know it aches
And your heart it breaks
And you can only take so much
Walk on, walk on
Home…hard to know what it is if you never had one
Home…I can’t say where it is but I know I’m going home
That’s where the heart is
I know it aches
How your heart it breaks
And you can only take so much
Walk on, walk on
Leave it behind
You’ve got to leave it behind
All that you fashion
All that you make
All that you build
All that you break
All that you measure
All that you steal
All this you can leave behind
All that you reason
All that you sense
All that you speak
All you dress up
All that you scheme…