Where are some subVI ?

[Lab]

Like DataSocketUpdate,I found DataSocketOpen SubVI colour of some example is different from Function Palette of LV7?Why?

[Al_S]

Some example VIs (like DS ReceiveImage.vi) use sub VIs (like DSOpenBuffered.vi) that were created for the examples. In general, to find the path of any VI or sub-VI, open the VI (if it's a sub-VI you can open it by double-clicking on its icon on the calling VI's diagram), and from the VI's menu, goto File >> VI Properties >> General: the path is shown as Location. If double-clicking on the icon doesn't open a front panel, the item may be a function, not a VI.
The DataSocket function panel includes the DataSocket Open function with a yellow icon. DS ReceiveImage.vi includes a sub VI DSOpenBuffered.vi with a white icon. DSOpenBuffered.vi is a VI that builds on the DataSocket Open function. If you open the diagram for DSOpenBuffered.vi, you'll see that it calls the
DataSocket Open function then uses a property node to setup a datasocket buffer.
Often, icons from NI are yellow for functions, white for VIs. It's just a visual clue to tell you what the item is.

[Lab]

ths.If I need some sub VIs that exist in some example,but I don't know there it is.What should I do?I want to know where I can see all available sub VIs?

[Al_S]

The examples are in multiple directories with many VIs in LLB files. I think the best way to browse them is to goto Help >> Find Examples from any LabView window. If you have opened a VI that uses a subVI you need, you can find the location of that subVI by going to File >> VI Properties as I explained in my earlier answer, or you can do a cut and paste from the diagram of the example to your diagram.
In LabView 7, you can also enable browsing LLB files using Windows Explorer: goto Tools >> Options to see that option. But I like searching or browsing using Find Examples: you can see the description of most example VIs as you browse them.