[hpsdr] Ozy and WinUSB

[Alberto I2PHD]

n3evl wrote:
> 
> I've no idea how important a criteria it is but I noticed when reading 
> up on winUSB that one feature it does NOT support is Isochronous 
> Transfers.  Maybe this is not relevant, but I seem to remember that this 
> was a factor in Flex choosing firewire over other alternatives for the 
> 5000.  I think this was in order to support multiple channels of data 
> while maintaining phase relationships. 

Yes, Isochronous Transfers are not supported by WinUSB. How important this
can be for an SDR application, I can't tell. IMHO, the phase relationship
between channels can be preserved by sending them interleaved on the same
bulk transfer... maybe....

But WinUSB has a great plus. WinUSB.dll is a user mode wrapper for WinUSB.sys
which is the kernel driver, and which is *signed*, being produced by Microsoft
itself. The 64-bit Windows 7, AFAIK, doesn't accept unsigned drivers.... and
the process of obtaining a 'signature' from Microsoft for a driver costs
a lot of money.... so WinUSB seems to be the only way to overcome this impasse...

73  Alberto  I2PHD

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