Harold Hallikainen wrote:
> I'm wondering about combining the USB mass storage class and  the HTTP 
> server in the Microchip TCP/IP stack. When someone plugs in a host 
> computer, the MSD appears on their machine. Click on index.html, and 
> you're at the user interface. Or, it could even include an autostart 
> file to start the  browser. You could, of course, look at files and 
> MAYBE even do GET cgi or MAYBE even POST.
> 
> Possible? Bad idea?

Probably a bad idea.

First of all, when you click on "index.html" in the file selector, the
browser is accessing it using "file:" protocol, not "http:". I have in
fact done an index on an archival CDROM in exactly this way, but it's
100% static pages accessed entirely with "file:" protocol. Such pages
CAN include browser-side Javascript (or even Java code) to make them
more interactive, but there's still no "server-side" processing going on.

The big problem with creating a server of some sort on the USB device is
that if the host operating system is treating the device as a MSD, then it
really, really does not expect the file structure or the contents of the
files to change by themselves -- this would screw up all of the internal
caching that it tries to do in order to optimize performance.

If you really need a server running on the USB device, then make it look
like a USB-to-Ethernet adapter, rather than a mass-storage device. Most
operating systems have support for that built-in.

-- Dave Tweed
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