Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>Timestamp the data external to the PC or use a real-time OS. Desktop OS that are really good at running Office and Firefox are spectacularly hopeless at real-time data acquisition. The drivers are optimized to signal the receipt of huge data buffers so as to maximize throughput of complex web pages and streamed media. Prompt signaling of the receipt of a couple of bytes, (or even 5K), is a bit below them - the drivers can't be bothered and tend to lie around for ages in case more data comes in, then they can signal it all at once :((</p> <p>All my embedded controllers that return data that needs to be time-stamped return the stamp in the data and do not rely on some megalithic desktop OS to wake up a thread in any sort of prompt manner.</p> <p>That said, you might be able to tweak the serial driver COMMTIMEOUTS to return data more quickly. Whether this will help much is another matter because you have other devices that may be subject to the same issues.</p> <p>Also, what is 'm_logFileStream'? Is this another async or otherwise queued disk write? If not, it should be.</p> <p>If you want to try to apply timestamps to data in the PC in the way you seem to want, then ideally all your data should flow through the same thread that adds the timestamps and does the logging. Writing multiple logs and filtering them afterwards to sort them into timestamp order is just going to add yet more jitter. That sort of thing is what Unix developers do because their computers can only execute bash scripts :))</p>
    singulars
    1. This table or related slice is empty.
    1. POTimestamping incoming serial data under WinXP 32 using Boost ASIO and Boost posix time?
      singulars
      1. PTQuestion
    1. PTAnswer
    1. This table or related slice is empty.
    1. USMartin James
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. POTimestamping incoming serial data under WinXP 32 using Boost ASIO and Boost posix time?
      singulars
      1. PTQuestion
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTAcceptedByOriginator
    1. COCheers @Martin, here's a bit more info: 1) I'm using boost::asio::serial. As far as I can find that won't give me access to the COMMTIMEOUTS for tweaking... 2) Unfortunately I can't apply timestamps externally for my range data, my device only spits out raw range readings. 3) m_logFileStream is a std::ofstream, which I believe will queue and be handled later 4) The other device I want to synchronise this data with doesn't have asynchronous read capabilities, it's a pain-in-the-ass module with a API written by a retarded monkey. This means my serial RX has to be handled in it's own thread.
      singulars
      1. PO
      1. USOcularProgrammer
    2. COI've now tried a few other things, and much as it pains me to admit this, I'm going to need to be a little smarter to make this work. I just can't get boost::asio to return any buffer larger than 3968 bytes. Why 3968 I have no idea but that seems to be the fundamental limit, so my idea of averaging out the error is dead in the water. Cheers for the advice mate.
      singulars
      1. PO
      1. USOcularProgrammer
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload