Re: Inofficial BlackBox 2.0

From: [at]} <Wojtek>
Date: Tue, 27 Nov 2007 11:17:26 -0500

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On Tue, 27 Nov 2007, CFB Software wrote:

> What sort of data transfer rates are you trying to achieve? I'm no expert in
> all aspects of this type of programming but I have had plenty of experience
> of the challenges of recording audio on Windows at ~170Kb per second without
> interruption for up to three hours continuously

We are aming at 50 MB/s continously for weeks at a time. The experiment is
going to run for years.

> This sort of data transfer
> is usually done by device drivers communicating with Windows at the hardware
> level and the Windows message loop being used by the application to transfer
> the data from the device driver to itself. Is that the approach that you are
> using or are you trying to control all of this at the BlackBox / application
> level?

I believe we will use this approach. We will customize a particular USB
driver, whose role after customization will be to gather USB data buffers
(1 kilobyte each) into long buffers, which will be presented to BlackBox
for processing. The driver may also pre-process the data somewhat, but
most of the processing will take place in BlackBox.

Another challenge is that the data stream has to be continously written to
disk. Yes, we know we will produce huge volumes of data. It is not clear
whether the USB driver or BB will write the files. We do not know yet
where are the bottlenecks in our DAQ system.

So, the processing chain will look like this:

                 50 MB/s
                USB-2 link
Custom hardware --------> PC --> USB driver --> BlackBox
FPGAs and USB-2 | |
                                      | or |
                                      V V
                                    disk disk


W.

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Received on Tue Nov 27 2007 - 17:17:26 UTC