Limit maximum buffer size as documented for AlazarBeforeAsyncRead #1535
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| # 64 MB see docs of AlazarBeforeAsyncRead | ||
| # http://www.alazartech.com/Support/Download%20Files/ATS-SDK-Guide-7.2.3.pdf#section*.110 | ||
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| requested_buffer_size = (bits_per_sample * samples_per_record * |
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I find it hard to understand why number_of_channels of channels is not involved in this formula. The respective formula in SDK pdf also does not contain number_of_channels. Why is that? Are on-board-memory-buffers considered per channel, and host-memory-buffers not?
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This buffer size is only a fraction of the total memory (1/64) in this case. I don't think that the limitation comes from filling the internal memory but from some other implementation detail that they don't reveal to use
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This buffer size is only a fraction of the total buffer size (1/64) in this case.
Sorry, i'm getting more confused. What did you mean with "this buffer size" and "total buffer size" and where does "1/64" comes from? and how does this relate to taking number_of_channels into account or not?
... from some other implementation detail ...
i agree with you, i have the same feeling.
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Sorry should have said total onboard memory. I mean given that we don't know the reason for this limitation (other than it's for sure not filling all the memory cf the card which would for sure depend on number of channels) all questions about this are speculations. This limitation might just be that the whatever fpga logic that captures data from a single channel only has a memory address space large enough to address 64 MB and there is a matching address space for the next channel. We really don't know at this stage.
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ok, thanks for explaining! I hope AlazarTech come back with useful answers :)
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@QCoDeS/core We don't really have a useful answer from AlazarTech. They confirm that this limit is here (at least on some cards) but also recommend to make the buffer smaller than this in general < 8 MB. |
Co-Authored-By: jenshnielsen <jenshnielsen@gmail.com>
As documented here http://www.alazartech.com/Support/Download%20Files/ATS-SDK-Guide-7.2.3.pdf#section*.110
We do not use the headers so that is not taken into account. My testing on the 9360 seems to indicate that it actually supports upto 96 MB but to stay on the safe side I have gone with the docs. We do not support and never will the old pci cards with lower limits so we do not need to take that into account