硬件驱动程序究竟要安几遍？
$考虑$ 很奇怪。还是上次摄像头导致电脑重启的问题，前几天总算把驱动盘翻了出来，重新安了一次。刚安好的时候试了一下没问题，本以为已经没事了，结果过两天再用，又蓝屏重启了。所以我说再试试其他的建议，把它接在另外一个USB接口上看看会不会这样。谁知道换到另外一个接口，找了半天以后，居然告诉我说发现新硬件，需要安装驱动程序。我好像从来没听谁说过，同一台电脑的不同USB接口，是不能共用硬件驱动的，这是怎么回事啊？难道我有三个USB接口，还必须把外接的硬件全部安三遍... 嘿嘿，这个问题以前研究过产生这种情况，是因为USB设备没有Serial Number，或者是SN无效
所以bus driver 就根据它的位置信息来生成InstanceID
如果指定了有效的SN，则系统就会始终将该设备识别成同一个设备，Instance ID就是SerialNumber
这个是当时找到的解释
Why does Windows not recognize my USB device as the same device if I plug it into a different port?
You may have noticed that if you take a USB device and plug it into your computer, Windows recognizes it and configures it. Then if you unplug it and replug it into a different USB port, Windows gets a bout of amnesia and thinks that it's a completely different device instead of using the settings that applied when you plugged it in last time. Why is that?
The USB device people explained that this happens when the device lacks a USB serial number.
Serial numbers are optional on USB devices. If the device has one, then Windows recognizes the device no matter which USB port you plug it into. But if it doesn't have a serial number, then Windows treats each appearance on a different USB port as if it were a new device.
(I remember that one major manufacturer of USB devices didn't quite understand how serial numbers worked. They gave all of their devices serial numbers, that's great, but they all got the same serial number. Exciting things happened if you plugged two of their devices into a computer at the same time.)
But why does Windows treat it as a different device if it lacks a serial number and shows up on a different port? Why can't it just say, "Oh, there you are, over there on another port."
Because that creates random behavior once you plug in two such devices. Depending on the order in which the devices get enumerated by Plug and Play, the two sets of settings would get assigned seemingly randomly at each boot. Today the settings match up one way, but tomorrow when the devices are enumerated in the other order, the settings are swapped. (You get similarly baffling behavior if you plug in the devices in different order.)
In other words: Things suck because (1) things were already in bad shape—this would not have been a problem if the device had a proper serial number—and (2) once you're in this bad state, the alternative sucks more. The USB stack is just trying to make the best of a bad situation without making it any worse.
quelle
http://blogs.msdn.com/oldnewthing/archive/2004/11/10/255047.aspx $郁闷$ 那没办法了，摄像头是别人帮我带的便宜货，是不是人家说的“山寨”货来着... 总是有得有失的嘛，8过这种简单的外设，其实倒真差不多，就是细节上可能不太在意
山寨货也不乏精品的
其实一直想不通，以手机为例，很多厂商完全有能力做出非常不错的东西，却不再外观设计上下功夫，非要去仿一个壳
回复 地板 的帖子
$考虑$ 这个没什么想不通的呀。模仿他人是争取被接受的敲门砖，山寨产品在没名气没顾客的时候打入市场困难，只好靠外形模仿来争取爱面子又钱不多的消费者群。等到自己做出名气了有能力开发引领市场了，就会开始把自己的产品跟别人产品的外形上做出差别。 很多大的山寨都做了5，6年了$m28$ $m28$ marketing太复杂，看来欧真的还是适合在后台做技术$m30$ $m30$ $汗$ 能做好一门专业已经很棒了... 可惜欧是wirtschafts informatik$m13$ $m13$ $m2$ 没啥，偶认识的读Winfo的有的偏info有的偏经济，都可以啊，就看你兴趣所在。
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